/*
* FFI (C89 API)
* (C) 2015,2017 Jack Lloyd
* (C) 2021 René Fischer
*
* Botan is released under the Simplified BSD License (see license.txt)
*/

#ifndef BOTAN_FFI_H_
#define BOTAN_FFI_H_

#ifdef __cplusplus
extern "C" {
#endif

/*
This header exports some of botan's functionality via a C89 interface. This API
is uesd by the Python, OCaml, Rust, Ruby, and Haskell bindings via those languages
respective ctypes/FFI libraries.

The API is intended to be as easy as possible to call from other
languages, which often have easy ways to call C, because C. But some C
code is easier to deal with than others, so to make things easy this
API follows a few simple rules:

- All interactions are via pointers to opaque structs. No need to worry about
  structure padding issues and the like.

- All functions return an int error code (except the version calls, which are
  assumed to always have something to say).

- Use simple types: size_t for lengths, const char* NULL terminated strings,
  uint8_t for binary.

- No ownership of memory transfers across the API boundary. The API will
  consume data from const pointers, and will produce output by writing to
  buffers provided by (and allocated by) the caller.

- If exporting a value (a string or a blob) the function takes a pointer to the
  output array and a read/write pointer to the length. If the length is insufficient, an
  error is returned. So passing nullptr/0 allows querying the final value.

  Typically there is also a function which allows querying the expected output
  length of a function, for example `botan_hash_output_length` allows knowing in
  advance the expected size for `botan_hash_final`. Some of these are exact,
  while others such as `botan_pk_op_decrypt_output_length` only provide an upper
  bound.

  The big exception to this currently is the various functions which serialize
  public and private keys, where there are currently no function that can
  estimate the serialized size. Here view functions are used; see the handbook
  for further details.

 TODO:
 - Doxygen comments for all functions/params
 - TLS
*/

#include <stddef.h>
#include <stdint.h>

/**
* The compile time API version. This matches the value of
* botan_ffi_api_version. This can be used for compile-time checking if a
* particular feature is available.
*
* Note this same value is also reflected in BOTAN_HAS_FFI in build.h, however
* that declaration is not visible here since this header is intentionally
* free-standing, depending only on a few C standard library headers.
*/
#define BOTAN_FFI_API_VERSION 20240408

/**
* BOTAN_FFI_EXPORT indicates public FFI functions.
*
* The arguments to the macro are to indicate the version that
* that particular FFI function was first available
*/
#if defined(BOTAN_DLL)
   #define BOTAN_FFI_EXPORT(maj, min) BOTAN_DLL
#else
   #if defined(__has_attribute)
      #if __has_attribute(visibility)
         #define BOTAN_FFI_EXPORT(maj, min) __attribute__((visibility("default")))
      #endif
   #elif defined(_MSC_VER) && !defined(BOTAN_IS_BEING_BUILT)
      #define BOTAN_FFI_EXPORT(maj, min) __declspec(dllimport)
   #else
      #define BOTAN_FFI_EXPORT(maj, min)
   #endif
#endif

#if !defined(BOTAN_NO_DEPRECATED_WARNINGS)
   #if defined(__has_attribute)
      #if __has_attribute(deprecated)
         #define BOTAN_FFI_DEPRECATED(msg) __attribute__((deprecated(msg)))
      #endif
   #elif defined(_MSC_VER)
      #define BOTAN_FFI_DEPRECATED(msg) __declspec(deprecated(msg))
   #endif
#endif

#if !defined(BOTAN_FFI_DEPRECATED)
   #define BOTAN_FFI_DEPRECATED(msg) /**/
#endif

/**
* Error codes
*
* If you add a new value here be sure to also add it in
* botan_error_description
*/
enum BOTAN_FFI_ERROR {
   BOTAN_FFI_SUCCESS = 0,
   BOTAN_FFI_INVALID_VERIFIER = 1,

   BOTAN_FFI_ERROR_INVALID_INPUT = -1,
   BOTAN_FFI_ERROR_BAD_MAC = -2,

   BOTAN_FFI_ERROR_INSUFFICIENT_BUFFER_SPACE = -10,
   BOTAN_FFI_ERROR_STRING_CONVERSION_ERROR = -11,

   BOTAN_FFI_ERROR_EXCEPTION_THROWN = -20,
   BOTAN_FFI_ERROR_OUT_OF_MEMORY = -21,
   BOTAN_FFI_ERROR_SYSTEM_ERROR = -22,
   BOTAN_FFI_ERROR_INTERNAL_ERROR = -23,

   BOTAN_FFI_ERROR_BAD_FLAG = -30,
   BOTAN_FFI_ERROR_NULL_POINTER = -31,
   BOTAN_FFI_ERROR_BAD_PARAMETER = -32,
   BOTAN_FFI_ERROR_KEY_NOT_SET = -33,
   BOTAN_FFI_ERROR_INVALID_KEY_LENGTH = -34,
   BOTAN_FFI_ERROR_INVALID_OBJECT_STATE = -35,

   BOTAN_FFI_ERROR_NOT_IMPLEMENTED = -40,
   BOTAN_FFI_ERROR_INVALID_OBJECT = -50,

   BOTAN_FFI_ERROR_TLS_ERROR = -75,
   BOTAN_FFI_ERROR_HTTP_ERROR = -76,
   BOTAN_FFI_ERROR_ROUGHTIME_ERROR = -77,
   BOTAN_FFI_ERROR_TPM_ERROR = -78,

   BOTAN_FFI_ERROR_UNKNOWN_ERROR = -100,
};

typedef void* botan_view_ctx;

/**
* Viewer function for binary data
*
* @param view_ctx some application context
* @param data the binary data
* @param len the length of data in bytes
*/
typedef int (*botan_view_bin_fn)(botan_view_ctx view_ctx, const uint8_t* data, size_t len);

/**
* Viewer function for string data
*
* @param view_ctx some application context
* @param str the null terminated string
* @param len the length of string *including* the null terminator
*/
typedef int (*botan_view_str_fn)(botan_view_ctx view_ctx, const char* str, size_t len);

/**
* Convert an error code into a string. Returns "Unknown error"
* if the error code is not a known one.
*/
BOTAN_FFI_EXPORT(2, 8) const char* botan_error_description(int err);

/**
* Return the message of the last exception caught in this thread.
*
* This pointer can/will be reallocated or overwritten the next time
* this thread calls any other Botan FFI function and must be copied
* to persistent storage first.
*/
BOTAN_FFI_EXPORT(3, 0) const char* botan_error_last_exception_message(void);

/**
* Return the version of the currently supported FFI API. This is
* expressed in the form YYYYMMDD of the release date of this version
* of the API.
*/
BOTAN_FFI_EXPORT(2, 0) uint32_t botan_ffi_api_version(void);

/**
* Return 0 (ok) if the version given is one this library supports.
* botan_ffi_supports_api(botan_ffi_api_version()) will always return 0.
*/
BOTAN_FFI_EXPORT(2, 0) int botan_ffi_supports_api(uint32_t api_version);

/**
* Return a free-form version string, e.g., 2.0.0
*/
BOTAN_FFI_EXPORT(2, 0) const char* botan_version_string(void);

/**
* Return the major version of the library
*/
BOTAN_FFI_EXPORT(2, 0) uint32_t botan_version_major(void);

/**
* Return the minor version of the library
*/
BOTAN_FFI_EXPORT(2, 0) uint32_t botan_version_minor(void);

/**
* Return the patch version of the library
*/
BOTAN_FFI_EXPORT(2, 0) uint32_t botan_version_patch(void);

/**
* Return the date this version was released as
* an integer, or 0 if an unreleased version
*/
BOTAN_FFI_EXPORT(2, 0) uint32_t botan_version_datestamp(void);

/**
* Returns 0 if x[0..len] == y[0..len], or otherwise -1
*/
BOTAN_FFI_EXPORT(2, 3) int botan_constant_time_compare(const uint8_t* x, const uint8_t* y, size_t len);

/**
* Deprecated equivalent to botan_constant_time_compare
*/
BOTAN_FFI_DEPRECATED("Use botan_constant_time_compare")
BOTAN_FFI_EXPORT(2, 0) int botan_same_mem(const uint8_t* x, const uint8_t* y, size_t len);

/**
* Clear out memory using a system specific approach to bypass elision by the
* compiler (currently using RtlSecureZeroMemory or tricks with volatile pointers).
*/
BOTAN_FFI_EXPORT(2, 2) int botan_scrub_mem(void* mem, size_t bytes);

#define BOTAN_FFI_HEX_LOWER_CASE 1

/**
* Perform hex encoding
* @param x is some binary data
* @param len length of x in bytes
* @param out an array of at least x*2 bytes
* @param flags flags out be upper or lower case?
* @return 0 on success, a negative value on failure
*/
BOTAN_FFI_EXPORT(2, 0) int botan_hex_encode(const uint8_t* x, size_t len, char* out, uint32_t flags);

/**
* Perform hex decoding
* @param hex_str a string of hex chars (whitespace is ignored)
* @param in_len the length of hex_str
* @param out the output buffer should be at least strlen(hex_str)/2 bytes
* @param out_len the size of the output buffer on input, set to the number of bytes written
* @return 0 on success, a negative value on failure
*/
BOTAN_FFI_EXPORT(2, 3) int botan_hex_decode(const char* hex_str, size_t in_len, uint8_t* out, size_t* out_len);

/**
* Perform base64 encoding
*/
BOTAN_FFI_EXPORT(2, 3) int botan_base64_encode(const uint8_t* x, size_t len, char* out, size_t* out_len);

/**
* Perform base64 decoding
*/
BOTAN_FFI_EXPORT(2, 3) int botan_base64_decode(const char* base64_str, size_t in_len, uint8_t* out, size_t* out_len);

/**
* RNG type
*/
typedef struct botan_rng_struct* botan_rng_t;

/**
* Initialize a random number generator object
* @param rng rng object
* @param rng_type type of the rng, possible values:
*    "system": system RNG
*    "esdm-full": ESDM RNG (fully seeded)
*    "esdm-pr": ESDM RNG (w. prediction resistance)
*    "user": userspace RNG
*    "user-threadsafe": userspace RNG, with internal locking
*    "rdrand": directly read RDRAND
* Set rng_type to null to let the library choose some default.
*/
BOTAN_FFI_EXPORT(2, 0) int botan_rng_init(botan_rng_t* rng, const char* rng_type);

/**
* Initialize a custom random number generator from a set of callback functions
* @param rng_out rng object to create
* @param rng_name name of the rng
* @param context An application-specific context passed to the callback functions
* @param get_cb Callback for getting random bytes from the rng, return 0 for success
* @param add_entropy_cb Callback for adding entropy to the rng, return 0 for success, may be NULL
* @param destroy_cb Callback called when rng is destroyed, may be NULL
*/
BOTAN_FFI_EXPORT(3, 0)
int botan_rng_init_custom(botan_rng_t* rng_out,
                          const char* rng_name,
                          void* context,
                          int (*get_cb)(void* context, uint8_t* out, size_t out_len),
                          int (*add_entropy_cb)(void* context, const uint8_t input[], size_t length),
                          void (*destroy_cb)(void* context));

/**
* Get random bytes from a random number generator
* @param rng rng object
* @param out output buffer of size out_len
* @param out_len number of requested bytes
* @return 0 on success, negative on failure
*/
BOTAN_FFI_EXPORT(2, 0) int botan_rng_get(botan_rng_t rng, uint8_t* out, size_t out_len);

/**
* Get random bytes from system random number generator
* @param out output buffer of size out_len
* @param out_len number of requested bytes
* @return 0 on success, negative on failure
*/
BOTAN_FFI_EXPORT(3, 0) int botan_system_rng_get(uint8_t* out, size_t out_len);

/**
* Reseed a random number generator
* Uses the System_RNG as a seed generator.
*
* @param rng rng object
* @param bits number of bits to reseed with
* @return 0 on success, a negative value on failure
*/
BOTAN_FFI_EXPORT(2, 0) int botan_rng_reseed(botan_rng_t rng, size_t bits);

/**
* Reseed a random number generator
*
* @param rng rng object
* @param source_rng the rng that will be read from
* @param bits number of bits to reseed with
* @return 0 on success, a negative value on failure
*/
BOTAN_FFI_EXPORT(2, 8) int botan_rng_reseed_from_rng(botan_rng_t rng, botan_rng_t source_rng, size_t bits);

/**
* Add some seed material to a random number generator
*
* @param rng rng object
* @param entropy the data to add
* @param entropy_len length of entropy buffer
* @return 0 on success, a negative value on failure
*/
BOTAN_FFI_EXPORT(2, 8) int botan_rng_add_entropy(botan_rng_t rng, const uint8_t* entropy, size_t entropy_len);

/**
* Frees all resources of the random number generator object
* @param rng rng object
* @return 0 if success, error if invalid object handle
*/
BOTAN_FFI_EXPORT(2, 0) int botan_rng_destroy(botan_rng_t rng);

/*
* Hash type
*/
typedef struct botan_hash_struct* botan_hash_t;

/**
* Initialize a hash function object
* @param hash hash object
* @param hash_name name of the hash function, e.g., "SHA-384"
* @param flags should be 0 in current API revision, all other uses are reserved
*       and return BOTAN_FFI_ERROR_BAD_FLAG
*/
BOTAN_FFI_EXPORT(2, 0) int botan_hash_init(botan_hash_t* hash, const char* hash_name, uint32_t flags);

/**
* Copy the state of a hash function object
* @param dest destination hash object
* @param source source hash object
* @return 0 on success, a negative value on failure
*/
BOTAN_FFI_EXPORT(2, 2) int botan_hash_copy_state(botan_hash_t* dest, botan_hash_t source);

/**
* Writes the output length of the hash function to *output_length
* @param hash hash object
* @param output_length output buffer to hold the hash function output length
* @return 0 on success, a negative value on failure
*/
BOTAN_FFI_EXPORT(2, 0) int botan_hash_output_length(botan_hash_t hash, size_t* output_length);

/**
* Writes the block size of the hash function to *block_size
* @param hash hash object
* @param block_size output buffer to hold the hash function output length
* @return 0 on success, a negative value on failure
*/
BOTAN_FFI_EXPORT(2, 2) int botan_hash_block_size(botan_hash_t hash, size_t* block_size);

/**
* Send more input to the hash function
* @param hash hash object
* @param in input buffer
* @param in_len number of bytes to read from the input buffer
* @return 0 on success, a negative value on failure
*/
BOTAN_FFI_EXPORT(2, 0) int botan_hash_update(botan_hash_t hash, const uint8_t* in, size_t in_len);

/**
* Finalizes the hash computation and writes the output to
* out[0:botan_hash_output_length()] then reinitializes for computing
* another digest as if botan_hash_clear had been called.
* @param hash hash object
* @param out output buffer
* @return 0 on success, a negative value on failure
*/
BOTAN_FFI_EXPORT(2, 0) int botan_hash_final(botan_hash_t hash, uint8_t out[]);

/**
* Reinitializes the state of the hash computation. A hash can
* be computed (with update/final) immediately.
* @param hash hash object
* @return 0 on success, a negative value on failure
*/
BOTAN_FFI_EXPORT(2, 0) int botan_hash_clear(botan_hash_t hash);

/**
* Frees all resources of the hash object
* @param hash hash object
* @return 0 if success, error if invalid object handle
*/
BOTAN_FFI_EXPORT(2, 0) int botan_hash_destroy(botan_hash_t hash);

/**
* Get the name of this hash function
* @param hash the object to read
* @param name output buffer
* @param name_len on input, the length of buffer, on success the number of bytes written
*/
BOTAN_FFI_EXPORT(2, 8) int botan_hash_name(botan_hash_t hash, char* name, size_t* name_len);

/*
* Message Authentication type
*/
typedef struct botan_mac_struct* botan_mac_t;

/**
* Initialize a message authentication code object
* @param mac mac object
* @param mac_name name of the hash function, e.g., "HMAC(SHA-384)"
* @param flags should be 0 in current API revision, all other uses are reserved
*       and return a negative value (error code)
* @return 0 on success, a negative value on failure
*/
BOTAN_FFI_EXPORT(2, 0) int botan_mac_init(botan_mac_t* mac, const char* mac_name, uint32_t flags);

/**
* Writes the output length of the message authentication code to *output_length
* @param mac mac object
* @param output_length output buffer to hold the MAC output length
* @return 0 on success, a negative value on failure
*/
BOTAN_FFI_EXPORT(2, 0) int botan_mac_output_length(botan_mac_t mac, size_t* output_length);

/**
* Sets the key on the MAC
* @param mac mac object
* @param key buffer holding the key
* @param key_len size of the key buffer in bytes
* @return 0 on success, a negative value on failure
*/
BOTAN_FFI_EXPORT(2, 0) int botan_mac_set_key(botan_mac_t mac, const uint8_t* key, size_t key_len);

/**
* Sets the nonce on the MAC
* @param mac mac object
* @param nonce buffer holding the key
* @param nonce_len size of the key buffer in bytes
* @return 0 on success, a negative value on failure
*/
BOTAN_FFI_EXPORT(3, 0) int botan_mac_set_nonce(botan_mac_t mac, const uint8_t* nonce, size_t nonce_len);

/**
* Send more input to the message authentication code
* @param mac mac object
* @param buf input buffer
* @param len number of bytes to read from the input buffer
* @return 0 on success, a negative value on failure
*/
BOTAN_FFI_EXPORT(2, 0) int botan_mac_update(botan_mac_t mac, const uint8_t* buf, size_t len);

/**
* Finalizes the MAC computation and writes the output to
* out[0:botan_mac_output_length()] then reinitializes for computing
* another MAC as if botan_mac_clear had been called.
* @param mac mac object
* @param out output buffer
* @return 0 on success, a negative value on failure
*/
BOTAN_FFI_EXPORT(2, 0) int botan_mac_final(botan_mac_t mac, uint8_t out[]);

/**
* Reinitializes the state of the MAC computation. A MAC can
* be computed (with update/final) immediately.
* @param mac mac object
* @return 0 on success, a negative value on failure
*/
BOTAN_FFI_EXPORT(2, 0) int botan_mac_clear(botan_mac_t mac);

/**
* Get the name of this MAC
* @param mac the object to read
* @param name output buffer
* @param name_len on input, the length of buffer, on success the number of bytes written
*/
BOTAN_FFI_EXPORT(2, 8) int botan_mac_name(botan_mac_t mac, char* name, size_t* name_len);

/**
* Get the key length limits of this auth code
* @param mac the object to read
* @param out_minimum_keylength if non-NULL, will be set to minimum keylength of MAC
* @param out_maximum_keylength if non-NULL, will be set to maximum keylength of MAC
* @param out_keylength_modulo if non-NULL will be set to byte multiple of valid keys
*/
BOTAN_FFI_EXPORT(2, 8)
int botan_mac_get_keyspec(botan_mac_t mac,
                          size_t* out_minimum_keylength,
                          size_t* out_maximum_keylength,
                          size_t* out_keylength_modulo);

/**
* Frees all resources of the MAC object
* @param mac mac object
* @return 0 if success, error if invalid object handle
*/
BOTAN_FFI_EXPORT(2, 0) int botan_mac_destroy(botan_mac_t mac);

/*
* Cipher modes
*/
typedef struct botan_cipher_struct* botan_cipher_t;

#define BOTAN_CIPHER_INIT_FLAG_MASK_DIRECTION 1
#define BOTAN_CIPHER_INIT_FLAG_ENCRYPT 0
#define BOTAN_CIPHER_INIT_FLAG_DECRYPT 1

/**
* Initialize a cipher object
*/
BOTAN_FFI_EXPORT(2, 0) int botan_cipher_init(botan_cipher_t* cipher, const char* name, uint32_t flags);

/**
* Return the name of the cipher object
*/
BOTAN_FFI_EXPORT(2, 8) int botan_cipher_name(botan_cipher_t cipher, char* name, size_t* name_len);

/**
* Return the output length of this cipher, for a particular input length.
*/
BOTAN_FFI_EXPORT(2, 8) int botan_cipher_output_length(botan_cipher_t cipher, size_t in_len, size_t* out_len);

/**
* Return if the specified nonce length is valid for this cipher
*/
BOTAN_FFI_EXPORT(2, 0) int botan_cipher_valid_nonce_length(botan_cipher_t cipher, size_t nl);

/**
* Get the tag length of the cipher (0 for non-AEAD modes)
*/
BOTAN_FFI_EXPORT(2, 0) int botan_cipher_get_tag_length(botan_cipher_t cipher, size_t* tag_size);

/**
* Returns 1 iff the cipher provides authentication as well as confidentiality.
*/
BOTAN_FFI_EXPORT(3, 3) int botan_cipher_is_authenticated(botan_cipher_t cipher);

/**
 * Returns 1 iff the cipher requires the entire message before any
 * encryption or decryption can be performed. No output data will be produced
 * in botan_cipher_update() until the final flag is set.
 */
BOTAN_FFI_EXPORT(3, 4) int botan_cipher_requires_entire_message(botan_cipher_t cipher);

/**
* Get the default nonce length of this cipher
*/
BOTAN_FFI_EXPORT(2, 0) int botan_cipher_get_default_nonce_length(botan_cipher_t cipher, size_t* nl);

/**
* Return the update granularity of the cipher; botan_cipher_update must be
* called with blocks of this size, except for the final.
*/
BOTAN_FFI_EXPORT(2, 0) int botan_cipher_get_update_granularity(botan_cipher_t cipher, size_t* ug);

/**
* Return the ideal update granularity of the cipher. This is some multiple of the
* update granularity, reflecting possibilities for optimization.
*/
BOTAN_FFI_EXPORT(3, 0) int botan_cipher_get_ideal_update_granularity(botan_cipher_t cipher, size_t* ug);

/**
* Get information about the key lengths. Prefer botan_cipher_get_keyspec
*/
BOTAN_FFI_EXPORT(2, 0)
int botan_cipher_query_keylen(botan_cipher_t, size_t* out_minimum_keylength, size_t* out_maximum_keylength);

/**
* Get information about the supported key lengths.
*/
BOTAN_FFI_EXPORT(2, 8)
int botan_cipher_get_keyspec(botan_cipher_t, size_t* min_keylen, size_t* max_keylen, size_t* mod_keylen);

/**
* Set the key for this cipher object
*/
BOTAN_FFI_EXPORT(2, 0) int botan_cipher_set_key(botan_cipher_t cipher, const uint8_t* key, size_t key_len);

/**
* Reset the message specific state for this cipher.
* Without resetting the keys, this resets the nonce, and any state
* associated with any message bits that have been processed so far.
*
* It is conceptually equivalent to calling botan_cipher_clear followed
* by botan_cipher_set_key with the original key.
*/
BOTAN_FFI_EXPORT(2, 8) int botan_cipher_reset(botan_cipher_t cipher);

/**
* Set the associated data. Will fail if cipher is not an AEAD
*/
BOTAN_FFI_EXPORT(2, 0) int botan_cipher_set_associated_data(botan_cipher_t cipher, const uint8_t* ad, size_t ad_len);

/**
* Begin processing a new message using the provided nonce
*/
BOTAN_FFI_EXPORT(2, 0) int botan_cipher_start(botan_cipher_t cipher, const uint8_t* nonce, size_t nonce_len);

#define BOTAN_CIPHER_UPDATE_FLAG_FINAL (1U << 0)

/**
* @brief Encrypt/Decrypt some data and/or finalize the encryption/decryption
*
* This encrypts as many bytes from @p input_bytes into @p output_bytes as
* possible. Unless ``BOTAN_CIPHER_UPDATE_FLAG_FINAL`` is set, this function will
* consume bytes in multiples of botan_cipher_get_update_granularity().
* @p input_consumed and @p output_written will be set accordingly and it is the
* caller's responsibility to adapt their buffers accordingly before calling this
* function again. Note that, unless ``BOTAN_CIPHER_UPDATE_FLAG_FINAL`` is set,
* the cipher will at most generate @p input_size output bytes.
*
* Eventually, the caller must set the ``BOTAN_CIPHER_UPDATE_FLAG_FINAL`` flag to
* indicate that no more input will be provided. This will cause the cipher to
* consume all given input bytes and produce the final output; or return a
* ``BOTAN_FFI_ERROR_INSUFFICIENT_BUFFER_SPACE`` error if the given output buffer
* was too small. In the latter case, @p output_written will be set to the
* required buffer size. Calling again with ``BOTAN_CIPHER_UPDATE_FLAG_FINAL``, a
* big enough buffer and no further input will then produce the final output.
*
* Note that some ciphers require the entire message to be provided before any
* output is produced. @sa botan_cipher_requires_entire_message().
*/
BOTAN_FFI_EXPORT(2, 0)
int botan_cipher_update(botan_cipher_t cipher,
                        uint32_t flags,
                        uint8_t output[],
                        size_t output_size,
                        size_t* output_written,
                        const uint8_t input_bytes[],
                        size_t input_size,
                        size_t* input_consumed);

/**
* Reset the key, nonce, AD and all other state on this cipher object
*/
BOTAN_FFI_EXPORT(2, 0) int botan_cipher_clear(botan_cipher_t hash);

/**
* Destroy the cipher object
* @return 0 if success, error if invalid object handle
*/
BOTAN_FFI_EXPORT(2, 0) int botan_cipher_destroy(botan_cipher_t cipher);

/*
* Derive a key from a passphrase for a number of iterations
* @param pbkdf_algo PBKDF algorithm, e.g., "PBKDF2(SHA-256)"
* @param out buffer to store the derived key, must be of out_len bytes
* @param out_len the desired length of the key to produce
* @param passphrase the password to derive the key from
* @param salt a randomly chosen salt
* @param salt_len length of salt in bytes
* @param iterations the number of iterations to use (use 10K or more)
* @return 0 on success, a negative value on failure
*
* Deprecated: use
*  botan_pwdhash(pbkdf_algo, iterations, 0, 0, out, out_len,
*                passphrase, 0, salt, salt_len);
*/
BOTAN_FFI_DEPRECATED("Use botan_pwdhash")
BOTAN_FFI_EXPORT(2, 0)
int botan_pbkdf(const char* pbkdf_algo,
                uint8_t out[],
                size_t out_len,
                const char* passphrase,
                const uint8_t salt[],
                size_t salt_len,
                size_t iterations);

/**
* Derive a key from a passphrase, running until msec time has elapsed.
* @param pbkdf_algo PBKDF algorithm, e.g., "PBKDF2(SHA-256)"
* @param out buffer to store the derived key, must be of out_len bytes
* @param out_len the desired length of the key to produce
* @param passphrase the password to derive the key from
* @param salt a randomly chosen salt
* @param salt_len length of salt in bytes
* @param milliseconds_to_run if iterations is zero, then instead the PBKDF is
*        run until milliseconds_to_run milliseconds has passed
* @param out_iterations_used set to the number iterations executed
* @return 0 on success, a negative value on failure
*
* Deprecated: use
*
* botan_pwdhash_timed(pbkdf_algo,
*                     static_cast<uint32_t>(ms_to_run),
*                     iterations_used,
*                     nullptr,
*                     nullptr,
*                     out, out_len,
*                     password, 0,
*                     salt, salt_len);
*/
BOTAN_FFI_EXPORT(2, 0)
int botan_pbkdf_timed(const char* pbkdf_algo,
                      uint8_t out[],
                      size_t out_len,
                      const char* passphrase,
                      const uint8_t salt[],
                      size_t salt_len,
                      size_t milliseconds_to_run,
                      size_t* out_iterations_used);

/*
* Derive a key from a passphrase
* @param algo PBKDF algorithm, e.g., "PBKDF2(SHA-256)" or "Scrypt"
* @param param1 the first PBKDF algorithm parameter
* @param param2 the second PBKDF algorithm parameter (may be zero if unneeded)
* @param param3 the third PBKDF algorithm parameter (may be zero if unneeded)
* @param out buffer to store the derived key, must be of out_len bytes
* @param out_len the desired length of the key to produce
* @param passphrase the password to derive the key from
* @param passphrase_len if > 0, specifies length of password. If len == 0, then
*        strlen will be called on passphrase to compute the length.
* @param salt a randomly chosen salt
* @param salt_len length of salt in bytes
* @return 0 on success, a negative value on failure
*/
int BOTAN_FFI_EXPORT(2, 8) botan_pwdhash(const char* algo,
                                         size_t param1,
                                         size_t param2,
                                         size_t param3,
                                         uint8_t out[],
                                         size_t out_len,
                                         const char* passphrase,
                                         size_t passphrase_len,
                                         const uint8_t salt[],
                                         size_t salt_len);

/*
* Derive a key from a passphrase
* @param pbkdf_algo PBKDF algorithm, e.g., "Scrypt" or "PBKDF2(SHA-256)"
* @param msec the desired runtime in milliseconds
* @param param1 will be set to the first password hash parameter
* @param param2 will be set to the second password hash parameter
* @param param3 will be set to the third password hash parameter
* @param out buffer to store the derived key, must be of out_len bytes
* @param out_len the desired length of the key to produce
* @param passphrase the password to derive the key from
* @param passphrase_len if > 0, specifies length of password. If len == 0, then
*        strlen will be called on passphrase to compute the length.
* @param salt a randomly chosen salt
* @param salt_len length of salt in bytes
* @return 0 on success, a negative value on failure
*/
int BOTAN_FFI_EXPORT(2, 8) botan_pwdhash_timed(const char* algo,
                                               uint32_t msec,
                                               size_t* param1,
                                               size_t* param2,
                                               size_t* param3,
                                               uint8_t out[],
                                               size_t out_len,
                                               const char* passphrase,
                                               size_t passphrase_len,
                                               const uint8_t salt[],
                                               size_t salt_len);

/**
* Derive a key using scrypt
* Deprecated; use
* botan_pwdhash("Scrypt", N, r, p, out, out_len, password, 0, salt, salt_len);
*/
BOTAN_FFI_DEPRECATED("Use botan_pwdhash")
BOTAN_FFI_EXPORT(2, 8)
int botan_scrypt(uint8_t out[],
                 size_t out_len,
                 const char* passphrase,
                 const uint8_t salt[],
                 size_t salt_len,
                 size_t N,
                 size_t r,
                 size_t p);

/**
* Derive a key
* @param kdf_algo KDF algorithm, e.g., "SP800-56C"
* @param out buffer holding the derived key, must be of length out_len
* @param out_len the desired output length in bytes
* @param secret the secret input
* @param secret_len size of secret in bytes
* @param salt a diversifier
* @param salt_len size of salt in bytes
* @param label purpose for the derived keying material
* @param label_len size of label in bytes
* @return 0 on success, a negative value on failure
*/
BOTAN_FFI_EXPORT(2, 0)
int botan_kdf(const char* kdf_algo,
              uint8_t out[],
              size_t out_len,
              const uint8_t secret[],
              size_t secret_len,
              const uint8_t salt[],
              size_t salt_len,
              const uint8_t label[],
              size_t label_len);

/*
* Raw Block Cipher (PRP) interface
*/
typedef struct botan_block_cipher_struct* botan_block_cipher_t;

/**
* Initialize a block cipher object
*/
BOTAN_FFI_EXPORT(2, 1) int botan_block_cipher_init(botan_block_cipher_t* bc, const char* cipher_name);

/**
* Destroy a block cipher object
* @return 0 if success, error if invalid object handle
*/
BOTAN_FFI_EXPORT(2, 1) int botan_block_cipher_destroy(botan_block_cipher_t bc);

/**
* Reinitializes the block cipher
* @return 0 on success, a negative value on failure
*/
BOTAN_FFI_EXPORT(2, 1) int botan_block_cipher_clear(botan_block_cipher_t bc);

/**
* Set the key for a block cipher instance
*/
BOTAN_FFI_EXPORT(2, 1) int botan_block_cipher_set_key(botan_block_cipher_t bc, const uint8_t key[], size_t len);

/**
* Return the positive block size of this block cipher, or negative to
* indicate an error
*/
BOTAN_FFI_EXPORT(2, 1) int botan_block_cipher_block_size(botan_block_cipher_t bc);

/**
* Encrypt one or more blocks with the cipher
*/
BOTAN_FFI_EXPORT(2, 1)
int botan_block_cipher_encrypt_blocks(botan_block_cipher_t bc, const uint8_t in[], uint8_t out[], size_t blocks);

/**
* Decrypt one or more blocks with the cipher
*/
BOTAN_FFI_EXPORT(2, 1)
int botan_block_cipher_decrypt_blocks(botan_block_cipher_t bc, const uint8_t in[], uint8_t out[], size_t blocks);

/**
* Get the name of this block cipher
* @param cipher the object to read
* @param name output buffer
* @param name_len on input, the length of buffer, on success the number of bytes written
*/
BOTAN_FFI_EXPORT(2, 8) int botan_block_cipher_name(botan_block_cipher_t cipher, char* name, size_t* name_len);

/**
* Get the key length limits of this block cipher
* @param cipher the object to read
* @param out_minimum_keylength if non-NULL, will be set to minimum keylength of cipher
* @param out_maximum_keylength if non-NULL, will be set to maximum keylength of cipher
* @param out_keylength_modulo if non-NULL will be set to byte multiple of valid keys
*/
BOTAN_FFI_EXPORT(2, 8)
int botan_block_cipher_get_keyspec(botan_block_cipher_t cipher,
                                   size_t* out_minimum_keylength,
                                   size_t* out_maximum_keylength,
                                   size_t* out_keylength_modulo);

/*
* Multiple precision integers (MPI)
*/
typedef struct botan_mp_struct* botan_mp_t;

/**
* Initialize an MPI
*/
BOTAN_FFI_EXPORT(2, 1) int botan_mp_init(botan_mp_t* mp);

/**
* Destroy (deallocate) an MPI
* @return 0 if success, error if invalid object handle
*/
BOTAN_FFI_EXPORT(2, 1) int botan_mp_destroy(botan_mp_t mp);

/**
* Convert the MPI to a hex string. Writes botan_mp_num_bytes(mp)*2 + 1 bytes
*/
BOTAN_FFI_EXPORT(2, 1) int botan_mp_to_hex(botan_mp_t mp, char* out);

/**
* Convert the MPI to a string. Currently base == 10 and base == 16 are supported.
*/
BOTAN_FFI_EXPORT(2, 1) int botan_mp_to_str(botan_mp_t mp, uint8_t base, char* out, size_t* out_len);

/**
* Set the MPI to zero
*/
BOTAN_FFI_EXPORT(2, 1) int botan_mp_clear(botan_mp_t mp);

/**
* Set the MPI value from an int
*/
BOTAN_FFI_EXPORT(2, 1) int botan_mp_set_from_int(botan_mp_t mp, int initial_value);

/**
* Set the MPI value from another MP object
*/
BOTAN_FFI_EXPORT(2, 1) int botan_mp_set_from_mp(botan_mp_t dest, botan_mp_t source);

/**
* Set the MPI value from a string
*/
BOTAN_FFI_EXPORT(2, 1) int botan_mp_set_from_str(botan_mp_t dest, const char* str);

/**
* Set the MPI value from a string with arbitrary radix.
* For arbitrary being 10 or 16.
*/
BOTAN_FFI_EXPORT(2, 1) int botan_mp_set_from_radix_str(botan_mp_t dest, const char* str, size_t radix);

/**
* Return the number of significant bits in the MPI
*/
BOTAN_FFI_EXPORT(2, 1) int botan_mp_num_bits(botan_mp_t n, size_t* bits);

/**
* Return the number of significant bytes in the MPI
*/
BOTAN_FFI_EXPORT(2, 1) int botan_mp_num_bytes(botan_mp_t n, size_t* bytes);

/*
* Convert the MPI to a big-endian binary string. Writes botan_mp_num_bytes to vec
*/
BOTAN_FFI_EXPORT(2, 1) int botan_mp_to_bin(botan_mp_t mp, uint8_t vec[]);

/*
* Set an MP to the big-endian binary value
*/
BOTAN_FFI_EXPORT(2, 1) int botan_mp_from_bin(botan_mp_t mp, const uint8_t vec[], size_t vec_len);

/*
* Convert the MPI to a uint32_t, if possible. Fails if MPI is negative or too large.
*/
BOTAN_FFI_EXPORT(2, 1) int botan_mp_to_uint32(botan_mp_t mp, uint32_t* val);

/**
* This function should have been named mp_is_non_negative. Returns 1
* iff mp is greater than *or equal to* zero. Use botan_mp_is_negative
* to detect negative numbers, botan_mp_is_zero to check for zero.
*/
BOTAN_FFI_EXPORT(2, 1) int botan_mp_is_positive(botan_mp_t mp);

/**
* Return 1 iff mp is less than 0
*/
BOTAN_FFI_EXPORT(2, 1) int botan_mp_is_negative(botan_mp_t mp);

BOTAN_FFI_EXPORT(2, 1) int botan_mp_flip_sign(botan_mp_t mp);

BOTAN_FFI_EXPORT(2, 1) int botan_mp_is_zero(botan_mp_t mp);

BOTAN_FFI_DEPRECATED("Use botan_mp_get_bit(0)") BOTAN_FFI_EXPORT(2, 1) int botan_mp_is_odd(botan_mp_t mp);
BOTAN_FFI_DEPRECATED("Use botan_mp_get_bit(0)") BOTAN_FFI_EXPORT(2, 1) int botan_mp_is_even(botan_mp_t mp);

BOTAN_FFI_EXPORT(2, 8) int botan_mp_add_u32(botan_mp_t result, botan_mp_t x, uint32_t y);
BOTAN_FFI_EXPORT(2, 8) int botan_mp_sub_u32(botan_mp_t result, botan_mp_t x, uint32_t y);

BOTAN_FFI_EXPORT(2, 1) int botan_mp_add(botan_mp_t result, botan_mp_t x, botan_mp_t y);
BOTAN_FFI_EXPORT(2, 1) int botan_mp_sub(botan_mp_t result, botan_mp_t x, botan_mp_t y);
BOTAN_FFI_EXPORT(2, 1) int botan_mp_mul(botan_mp_t result, botan_mp_t x, botan_mp_t y);

BOTAN_FFI_EXPORT(2, 1)
int botan_mp_div(botan_mp_t quotient, botan_mp_t remainder, botan_mp_t x, botan_mp_t y);

BOTAN_FFI_EXPORT(2, 1)
int botan_mp_mod_mul(botan_mp_t result, botan_mp_t x, botan_mp_t y, botan_mp_t mod);

/*
* Returns 0 if x != y
* Returns 1 if x == y
* Returns negative number on error
*/
BOTAN_FFI_EXPORT(2, 1) int botan_mp_equal(botan_mp_t x, botan_mp_t y);

/*
* Sets *result to comparison result:
* -1 if x < y, 0 if x == y, 1 if x > y
* Returns negative number on error or zero on success
*/
BOTAN_FFI_EXPORT(2, 1) int botan_mp_cmp(int* result, botan_mp_t x, botan_mp_t y);

/*
* Swap two botan_mp_t
*/
BOTAN_FFI_EXPORT(2, 1) int botan_mp_swap(botan_mp_t x, botan_mp_t y);

/* Return (base^exponent) % modulus */
BOTAN_FFI_EXPORT(2, 1)
int botan_mp_powmod(botan_mp_t out, botan_mp_t base, botan_mp_t exponent, botan_mp_t modulus);

BOTAN_FFI_EXPORT(2, 1) int botan_mp_lshift(botan_mp_t out, botan_mp_t in, size_t shift);
BOTAN_FFI_EXPORT(2, 1) int botan_mp_rshift(botan_mp_t out, botan_mp_t in, size_t shift);

BOTAN_FFI_EXPORT(2, 1) int botan_mp_mod_inverse(botan_mp_t out, botan_mp_t in, botan_mp_t modulus);

BOTAN_FFI_EXPORT(2, 1) int botan_mp_rand_bits(botan_mp_t rand_out, botan_rng_t rng, size_t bits);

BOTAN_FFI_EXPORT(2, 1)
int botan_mp_rand_range(botan_mp_t rand_out, botan_rng_t rng, botan_mp_t lower_bound, botan_mp_t upper_bound);

BOTAN_FFI_EXPORT(2, 1) int botan_mp_gcd(botan_mp_t out, botan_mp_t x, botan_mp_t y);

/**
* Returns 0 if n is not prime
* Returns 1 if n is prime
* Returns negative number on error
*/
BOTAN_FFI_EXPORT(2, 1) int botan_mp_is_prime(botan_mp_t n, botan_rng_t rng, size_t test_prob);

/**
* Returns 0 if specified bit of n is not set
* Returns 1 if specified bit of n is set
* Returns negative number on error
*/
BOTAN_FFI_EXPORT(2, 1) int botan_mp_get_bit(botan_mp_t n, size_t bit);

/**
* Set the specified bit
*/
BOTAN_FFI_EXPORT(2, 1) int botan_mp_set_bit(botan_mp_t n, size_t bit);

/**
* Clear the specified bit
*/
BOTAN_FFI_EXPORT(2, 1) int botan_mp_clear_bit(botan_mp_t n, size_t bit);

/* Bcrypt password hashing */

/**
* Create a password hash using Bcrypt
* @param out buffer holding the password hash, should be of length 64 bytes
* @param out_len the desired output length in bytes
* @param password the password
* @param rng a random number generator
* @param work_factor how much work to do to slow down guessing attacks
* @param flags should be 0 in current API revision, all other uses are reserved
*       and return BOTAN_FFI_ERROR_BAD_FLAG
* @return 0 on success, a negative value on failure

* Output is formatted bcrypt $2a$...
*/
BOTAN_FFI_EXPORT(2, 0)
int botan_bcrypt_generate(
   uint8_t* out, size_t* out_len, const char* password, botan_rng_t rng, size_t work_factor, uint32_t flags);

/**
* Check a previously created password hash
* @param pass the password to check against
* @param hash the stored hash to check against
* @return 0 if if this password/hash combination is valid,
*       1 if the combination is not valid (but otherwise well formed),
*       negative on error
*/
BOTAN_FFI_EXPORT(2, 0) int botan_bcrypt_is_valid(const char* pass, const char* hash);

/*
* Public/private key creation, import, ...
*/
typedef struct botan_privkey_struct* botan_privkey_t;

/**
* Create a new private key
* @param key the new object will be placed here
* @param algo_name something like "RSA" or "ECDSA"
* @param algo_params is specific to the algorithm. For RSA, specifies
*        the modulus bit length. For ECC is the name of the curve.
* @param rng a random number generator
*/
BOTAN_FFI_EXPORT(2, 0)
int botan_privkey_create(botan_privkey_t* key, const char* algo_name, const char* algo_params, botan_rng_t rng);

#define BOTAN_CHECK_KEY_EXPENSIVE_TESTS 1

BOTAN_FFI_EXPORT(2, 0) int botan_privkey_check_key(botan_privkey_t key, botan_rng_t rng, uint32_t flags);

BOTAN_FFI_DEPRECATED("Use botan_privkey_create")
BOTAN_FFI_EXPORT(2, 0) int botan_privkey_create_rsa(botan_privkey_t* key, botan_rng_t rng, size_t n_bits);
BOTAN_FFI_DEPRECATED("Use botan_privkey_create")
BOTAN_FFI_EXPORT(2, 0) int botan_privkey_create_ecdsa(botan_privkey_t* key, botan_rng_t rng, const char* params);
BOTAN_FFI_DEPRECATED("Use botan_privkey_create")
BOTAN_FFI_EXPORT(2, 0) int botan_privkey_create_ecdh(botan_privkey_t* key, botan_rng_t rng, const char* params);
BOTAN_FFI_DEPRECATED("Use botan_privkey_create")
BOTAN_FFI_EXPORT(2, 0) int botan_privkey_create_mceliece(botan_privkey_t* key, botan_rng_t rng, size_t n, size_t t);
BOTAN_FFI_DEPRECATED("Use botan_privkey_create")
BOTAN_FFI_EXPORT(2, 0) int botan_privkey_create_dh(botan_privkey_t* key, botan_rng_t rng, const char* param);

/**
 * Generates DSA key pair. Gives to a caller control over key length
 * and order of a subgroup 'q'.
 *
 * @param   key   handler to the resulting key
 * @param   rng   initialized PRNG
 * @param   pbits length of the key in bits. Must be between in range (1024, 3072)
 *          and multiple of 64. Bit size of the prime 'p'
 * @param   qbits order of the subgroup. Must be in range (160, 256) and multiple
 *          of 8
 *
 * @returns BOTAN_FFI_SUCCESS Success, `key' initialized with DSA key
 * @returns BOTAN_FFI_ERROR_NULL_POINTER  either `key' or `rng' is NULL
 * @returns BOTAN_FFI_ERROR_BAD_PARAMETER unexpected value for either `pbits' or
 *          `qbits'
 * @returns BOTAN_FFI_ERROR_NOT_IMPLEMENTED functionality not implemented
 *
*/
BOTAN_FFI_EXPORT(2, 5) int botan_privkey_create_dsa(botan_privkey_t* key, botan_rng_t rng, size_t pbits, size_t qbits);

/**
 * Generates ElGamal key pair. Caller has a control over key length
 * and order of a subgroup 'q'. Function is able to use two types of
 * primes:
 *    * if pbits-1 == qbits then safe primes are used for key generation
 *    * otherwise generation uses group of prime order
 *
 * @param   key   handler to the resulting key
 * @param   rng   initialized PRNG
 * @param   pbits length of the key in bits. Must be at least 1024
 * @param   qbits order of the subgroup. Must be at least 160
 *
 * @returns BOTAN_FFI_SUCCESS Success, `key' initialized with DSA key
 * @returns BOTAN_FFI_ERROR_NULL_POINTER  either `key' or `rng' is NULL
 * @returns BOTAN_FFI_ERROR_BAD_PARAMETER unexpected value for either `pbits' or
 *          `qbits'
 * @returns BOTAN_FFI_ERROR_NOT_IMPLEMENTED functionality not implemented
 *
*/
BOTAN_FFI_EXPORT(2, 5)
int botan_privkey_create_elgamal(botan_privkey_t* key, botan_rng_t rng, size_t pbits, size_t qbits);

/**
* Input currently assumed to be PKCS #8 structure;
* Set password to NULL to indicate no encryption expected
* Starting in 2.8.0, the rng parameter is unused and may be set to null
*/
BOTAN_FFI_EXPORT(2, 0)
int botan_privkey_load(botan_privkey_t* key, botan_rng_t rng, const uint8_t bits[], size_t len, const char* password);

/**
* @return 0 if success, error if invalid object handle
*/
BOTAN_FFI_EXPORT(2, 0) int botan_privkey_destroy(botan_privkey_t key);

#define BOTAN_PRIVKEY_EXPORT_FLAG_DER 0
#define BOTAN_PRIVKEY_EXPORT_FLAG_PEM 1
#define BOTAN_PRIVKEY_EXPORT_FLAG_RAW 2

/**
* On input *out_len is number of bytes in out[]
* On output *out_len is number of bytes written (or required)
* If out is not big enough no output is written, *out_len is set and 1 is returned
* Returns 0 on success and sets
* If some other error occurs a negative integer is returned.
*/
BOTAN_FFI_EXPORT(2, 0) int botan_privkey_export(botan_privkey_t key, uint8_t out[], size_t* out_len, uint32_t flags);

/**
* View the private key's DER encoding
*/
BOTAN_FFI_EXPORT(3, 0) int botan_privkey_view_der(botan_privkey_t key, botan_view_ctx ctx, botan_view_bin_fn view);

/**
* View the private key's PEM encoding
*/
BOTAN_FFI_EXPORT(3, 0) int botan_privkey_view_pem(botan_privkey_t key, botan_view_ctx ctx, botan_view_str_fn view);

/**
* View the private key's raw encoding
*/
BOTAN_FFI_EXPORT(3, 6) int botan_privkey_view_raw(botan_privkey_t key, botan_view_ctx ctx, botan_view_bin_fn view);

BOTAN_FFI_EXPORT(2, 8) int botan_privkey_algo_name(botan_privkey_t key, char out[], size_t* out_len);

/**
* Set encryption_algo to NULL or "" to have the library choose a default (recommended)
*/
BOTAN_FFI_DEPRECATED("Use botan_privkey_export_encrypted_pbkdf_{msec,iter}")
BOTAN_FFI_EXPORT(2, 0)
int botan_privkey_export_encrypted(botan_privkey_t key,
                                   uint8_t out[],
                                   size_t* out_len,
                                   botan_rng_t rng,
                                   const char* passphrase,
                                   const char* encryption_algo,
                                   uint32_t flags);

/*
* Export a private key, running PBKDF for specified amount of time
* @param key the private key to export
*
* Note: starting in 3.0, the output iterations count is not provided
*/
BOTAN_FFI_EXPORT(2, 0)
int botan_privkey_export_encrypted_pbkdf_msec(botan_privkey_t key,
                                              uint8_t out[],
                                              size_t* out_len,
                                              botan_rng_t rng,
                                              const char* passphrase,
                                              uint32_t pbkdf_msec_runtime,
                                              size_t* pbkdf_iterations_out,
                                              const char* cipher_algo,
                                              const char* pbkdf_algo,
                                              uint32_t flags);

/**
* Export a private key using the specified number of iterations.
*/
BOTAN_FFI_EXPORT(2, 0)
int botan_privkey_export_encrypted_pbkdf_iter(botan_privkey_t key,
                                              uint8_t out[],
                                              size_t* out_len,
                                              botan_rng_t rng,
                                              const char* passphrase,
                                              size_t pbkdf_iterations,
                                              const char* cipher_algo,
                                              const char* pbkdf_algo,
                                              uint32_t flags);

/**
* View the encryption of a private key (binary DER encoding)
*
* Set cipher_algo, pbkdf_algo to NULL to use defaults
* Set pbkdf_iterations to 0 to use defaults
*/
BOTAN_FFI_EXPORT(3, 0)
int botan_privkey_view_encrypted_der(botan_privkey_t key,
                                     botan_rng_t rng,
                                     const char* passphrase,
                                     const char* cipher_algo,
                                     const char* pbkdf_algo,
                                     size_t pbkdf_iterations,
                                     botan_view_ctx ctx,
                                     botan_view_bin_fn view);

/**
* View the encryption of a private key (binary DER encoding)
*
* Set cipher_algo, pbkdf_algo to NULL to use defaults
*/
BOTAN_FFI_EXPORT(3, 0)
int botan_privkey_view_encrypted_der_timed(botan_privkey_t key,
                                           botan_rng_t rng,
                                           const char* passphrase,
                                           const char* cipher_algo,
                                           const char* pbkdf_algo,
                                           size_t pbkdf_runtime_msec,
                                           botan_view_ctx ctx,
                                           botan_view_bin_fn view);

/**
* View the encryption of a private key (PEM encoding)
*
* Set cipher_algo, pbkdf_algo to NULL to use defaults
* Set pbkdf_iterations to 0 to use defaults
*/
BOTAN_FFI_EXPORT(3, 0)
int botan_privkey_view_encrypted_pem(botan_privkey_t key,
                                     botan_rng_t rng,
                                     const char* passphrase,
                                     const char* cipher_algo,
                                     const char* pbkdf_algo,
                                     size_t pbkdf_iterations,
                                     botan_view_ctx ctx,
                                     botan_view_str_fn view);

/**
* View the encryption of a private key (PEM encoding)
*
* Set cipher_algo, pbkdf_algo to NULL to use defaults
*/
BOTAN_FFI_EXPORT(3, 0)
int botan_privkey_view_encrypted_pem_timed(botan_privkey_t key,
                                           botan_rng_t rng,
                                           const char* passphrase,
                                           const char* cipher_algo,
                                           const char* pbkdf_algo,
                                           size_t pbkdf_runtime_msec,
                                           botan_view_ctx ctx,
                                           botan_view_str_fn view);

typedef struct botan_pubkey_struct* botan_pubkey_t;

BOTAN_FFI_EXPORT(2, 0) int botan_pubkey_load(botan_pubkey_t* key, const uint8_t bits[], size_t len);

BOTAN_FFI_EXPORT(2, 0) int botan_privkey_export_pubkey(botan_pubkey_t* out, botan_privkey_t in);

BOTAN_FFI_EXPORT(2, 0) int botan_pubkey_export(botan_pubkey_t key, uint8_t out[], size_t* out_len, uint32_t flags);

/**
* View the public key's DER encoding
*/
BOTAN_FFI_EXPORT(3, 0) int botan_pubkey_view_der(botan_pubkey_t key, botan_view_ctx ctx, botan_view_bin_fn view);

/**
* View the public key's PEM encoding
*/
BOTAN_FFI_EXPORT(3, 0) int botan_pubkey_view_pem(botan_pubkey_t key, botan_view_ctx ctx, botan_view_str_fn view);

/**
* View the public key's raw encoding
*/
BOTAN_FFI_EXPORT(3, 6) int botan_pubkey_view_raw(botan_pubkey_t key, botan_view_ctx ctx, botan_view_bin_fn view);

BOTAN_FFI_EXPORT(2, 0) int botan_pubkey_algo_name(botan_pubkey_t key, char out[], size_t* out_len);

/**
* Returns 0 if key is valid, negative if invalid key or some other error
*/
BOTAN_FFI_EXPORT(2, 0) int botan_pubkey_check_key(botan_pubkey_t key, botan_rng_t rng, uint32_t flags);

BOTAN_FFI_EXPORT(2, 0) int botan_pubkey_estimated_strength(botan_pubkey_t key, size_t* estimate);

BOTAN_FFI_EXPORT(2, 0)
int botan_pubkey_fingerprint(botan_pubkey_t key, const char* hash, uint8_t out[], size_t* out_len);

/**
* @return 0 if success, error if invalid object handle
*/
BOTAN_FFI_EXPORT(2, 0) int botan_pubkey_destroy(botan_pubkey_t key);

/*
* Get arbitrary named fields from public or private keys
*/
BOTAN_FFI_EXPORT(2, 0) int botan_pubkey_get_field(botan_mp_t output, botan_pubkey_t key, const char* field_name);

BOTAN_FFI_EXPORT(2, 0) int botan_privkey_get_field(botan_mp_t output, botan_privkey_t key, const char* field_name);

/*
* Algorithm specific key operations: RSA
*/
BOTAN_FFI_EXPORT(2, 0) int botan_privkey_load_rsa(botan_privkey_t* key, botan_mp_t p, botan_mp_t q, botan_mp_t e);

BOTAN_FFI_EXPORT(2, 8) int botan_privkey_load_rsa_pkcs1(botan_privkey_t* key, const uint8_t bits[], size_t len);

BOTAN_FFI_DEPRECATED("Use botan_privkey_get_field")
BOTAN_FFI_EXPORT(2, 0) int botan_privkey_rsa_get_p(botan_mp_t p, botan_privkey_t rsa_key);
BOTAN_FFI_DEPRECATED("Use botan_privkey_get_field")
BOTAN_FFI_EXPORT(2, 0) int botan_privkey_rsa_get_q(botan_mp_t q, botan_privkey_t rsa_key);
BOTAN_FFI_DEPRECATED("Use botan_privkey_get_field")
BOTAN_FFI_EXPORT(2, 0) int botan_privkey_rsa_get_d(botan_mp_t d, botan_privkey_t rsa_key);
BOTAN_FFI_DEPRECATED("Use botan_privkey_get_field")
BOTAN_FFI_EXPORT(2, 0) int botan_privkey_rsa_get_n(botan_mp_t n, botan_privkey_t rsa_key);
BOTAN_FFI_DEPRECATED("Use botan_privkey_get_field")
BOTAN_FFI_EXPORT(2, 0) int botan_privkey_rsa_get_e(botan_mp_t e, botan_privkey_t rsa_key);

BOTAN_FFI_EXPORT(2, 8)
int botan_privkey_rsa_get_privkey(botan_privkey_t rsa_key, uint8_t out[], size_t* out_len, uint32_t flags);

BOTAN_FFI_EXPORT(2, 0) int botan_pubkey_load_rsa(botan_pubkey_t* key, botan_mp_t n, botan_mp_t e);

BOTAN_FFI_DEPRECATED("Use botan_pubkey_get_field")
BOTAN_FFI_EXPORT(2, 0) int botan_pubkey_rsa_get_e(botan_mp_t e, botan_pubkey_t rsa_key);
BOTAN_FFI_DEPRECATED("Use botan_pubkey_get_field")
BOTAN_FFI_EXPORT(2, 0) int botan_pubkey_rsa_get_n(botan_mp_t n, botan_pubkey_t rsa_key);

/*
* Algorithm specific key operations: DSA
*/
BOTAN_FFI_EXPORT(2, 0)
int botan_privkey_load_dsa(botan_privkey_t* key, botan_mp_t p, botan_mp_t q, botan_mp_t g, botan_mp_t x);

BOTAN_FFI_EXPORT(2, 0)
int botan_pubkey_load_dsa(botan_pubkey_t* key, botan_mp_t p, botan_mp_t q, botan_mp_t g, botan_mp_t y);

BOTAN_FFI_DEPRECATED("Use botan_privkey_get_field")
BOTAN_FFI_EXPORT(2, 0) int botan_privkey_dsa_get_x(botan_mp_t n, botan_privkey_t key);

BOTAN_FFI_DEPRECATED("Use botan_pubkey_get_field")
BOTAN_FFI_EXPORT(2, 0) int botan_pubkey_dsa_get_p(botan_mp_t p, botan_pubkey_t key);
BOTAN_FFI_DEPRECATED("Use botan_pubkey_get_field")
BOTAN_FFI_EXPORT(2, 0) int botan_pubkey_dsa_get_q(botan_mp_t q, botan_pubkey_t key);
BOTAN_FFI_DEPRECATED("Use botan_pubkey_get_field")
BOTAN_FFI_EXPORT(2, 0) int botan_pubkey_dsa_get_g(botan_mp_t d, botan_pubkey_t key);
BOTAN_FFI_DEPRECATED("Use botan_pubkey_get_field")
BOTAN_FFI_EXPORT(2, 0) int botan_pubkey_dsa_get_y(botan_mp_t y, botan_pubkey_t key);

/*
* Loads Diffie Hellman private key
*
* @param key variable populated with key material
* @param p prime order of a Z_p group
* @param g group generator
* @param x private key
*
* @pre key is NULL on input
* @post function allocates memory and assigns to `key'
*
* @return 0 on success, a negative value on failure
*/
BOTAN_FFI_EXPORT(2, 0) int botan_privkey_load_dh(botan_privkey_t* key, botan_mp_t p, botan_mp_t g, botan_mp_t x);
/**
* Loads Diffie Hellman public key
*
* @param key variable populated with key material
* @param p prime order of a Z_p group
* @param g group generator
* @param y public key
*
* @pre key is NULL on input
* @post function allocates memory and assigns to `key'
*
* @return 0 on success, a negative value on failure
*/
BOTAN_FFI_EXPORT(2, 0) int botan_pubkey_load_dh(botan_pubkey_t* key, botan_mp_t p, botan_mp_t g, botan_mp_t y);

/*
* Algorithm specific key operations: ElGamal
*/

/**
* Loads ElGamal public key
* @param key variable populated with key material
* @param p prime order of a Z_p group
* @param g group generator
* @param y public key
*
* @pre key is NULL on input
* @post function allocates memory and assigns to `key'
*
* @return 0 on success, a negative value on failure
*/
BOTAN_FFI_EXPORT(2, 0) int botan_pubkey_load_elgamal(botan_pubkey_t* key, botan_mp_t p, botan_mp_t g, botan_mp_t y);

/**
* Loads ElGamal private key
*
* @param key variable populated with key material
* @param p prime order of a Z_p group
* @param g group generator
* @param x private key
*
* @pre key is NULL on input
* @post function allocates memory and assigns to `key'
*
* @return 0 on success, a negative value on failure
*/
BOTAN_FFI_EXPORT(2, 0) int botan_privkey_load_elgamal(botan_privkey_t* key, botan_mp_t p, botan_mp_t g, botan_mp_t x);

/*
* Algorithm specific key operations: Ed25519
*/

BOTAN_FFI_EXPORT(2, 2) int botan_privkey_load_ed25519(botan_privkey_t* key, const uint8_t privkey[32]);

BOTAN_FFI_EXPORT(2, 2) int botan_pubkey_load_ed25519(botan_pubkey_t* key, const uint8_t pubkey[32]);

BOTAN_FFI_EXPORT(2, 2) int botan_privkey_ed25519_get_privkey(botan_privkey_t key, uint8_t output[64]);

BOTAN_FFI_EXPORT(2, 2) int botan_pubkey_ed25519_get_pubkey(botan_pubkey_t key, uint8_t pubkey[32]);

/*
* Algorithm specific key operations: Ed448
*/

BOTAN_FFI_EXPORT(3, 4) int botan_privkey_load_ed448(botan_privkey_t* key, const uint8_t privkey[57]);

BOTAN_FFI_EXPORT(3, 4) int botan_pubkey_load_ed448(botan_pubkey_t* key, const uint8_t pubkey[57]);

BOTAN_FFI_EXPORT(3, 4) int botan_privkey_ed448_get_privkey(botan_privkey_t key, uint8_t output[57]);

BOTAN_FFI_EXPORT(3, 4) int botan_pubkey_ed448_get_pubkey(botan_pubkey_t key, uint8_t pubkey[57]);

/*
* Algorithm specific key operations: X25519
*/

BOTAN_FFI_EXPORT(2, 8) int botan_privkey_load_x25519(botan_privkey_t* key, const uint8_t privkey[32]);

BOTAN_FFI_EXPORT(2, 8) int botan_pubkey_load_x25519(botan_pubkey_t* key, const uint8_t pubkey[32]);

BOTAN_FFI_EXPORT(2, 8) int botan_privkey_x25519_get_privkey(botan_privkey_t key, uint8_t output[32]);

BOTAN_FFI_EXPORT(2, 8) int botan_pubkey_x25519_get_pubkey(botan_pubkey_t key, uint8_t pubkey[32]);

/*
* Algorithm specific key operations: X448
*/

BOTAN_FFI_EXPORT(3, 4) int botan_privkey_load_x448(botan_privkey_t* key, const uint8_t privkey[56]);

BOTAN_FFI_EXPORT(3, 4) int botan_pubkey_load_x448(botan_pubkey_t* key, const uint8_t pubkey[56]);

BOTAN_FFI_EXPORT(3, 4) int botan_privkey_x448_get_privkey(botan_privkey_t key, uint8_t output[56]);

BOTAN_FFI_EXPORT(3, 4) int botan_pubkey_x448_get_pubkey(botan_pubkey_t key, uint8_t pubkey[56]);

/*
* Algorithm specific key operations: ML-DSA
*/

BOTAN_FFI_EXPORT(3, 6)
int botan_privkey_load_ml_dsa(botan_privkey_t* key, const uint8_t privkey[], size_t key_len, const char* mldsa_mode);

BOTAN_FFI_EXPORT(3, 6)
int botan_pubkey_load_ml_dsa(botan_pubkey_t* key, const uint8_t pubkey[], size_t key_len, const char* mldsa_mode);

/*
* Algorithm specific key operations: Kyber
*/

BOTAN_FFI_EXPORT(3, 1) int botan_privkey_load_kyber(botan_privkey_t* key, const uint8_t privkey[], size_t key_len);

BOTAN_FFI_EXPORT(3, 1) int botan_pubkey_load_kyber(botan_pubkey_t* key, const uint8_t pubkey[], size_t key_len);

BOTAN_FFI_DEPRECATED("Use generic botan_privkey_view_raw")
BOTAN_FFI_EXPORT(3, 1)
int botan_privkey_view_kyber_raw_key(botan_privkey_t key, botan_view_ctx ctx, botan_view_bin_fn view);

BOTAN_FFI_DEPRECATED("Use generic botan_pubkey_view_raw")
BOTAN_FFI_EXPORT(3, 1)
int botan_pubkey_view_kyber_raw_key(botan_pubkey_t key, botan_view_ctx ctx, botan_view_bin_fn view);

/**
* Algorithm specific key operation: FrodoKEM
*/

BOTAN_FFI_EXPORT(3, 6)
int botan_privkey_load_frodokem(botan_privkey_t* key, const uint8_t privkey[], size_t key_len, const char* frodo_mode);

BOTAN_FFI_EXPORT(3, 6)
int botan_pubkey_load_frodokem(botan_pubkey_t* key, const uint8_t pubkey[], size_t key_len, const char* frodo_mode);

/**
* Algorithm specific key operation: Classic McEliece
*/

BOTAN_FFI_EXPORT(3, 6)
int botan_privkey_load_classic_mceliece(botan_privkey_t* key,
                                        const uint8_t privkey[],
                                        size_t key_len,
                                        const char* cmce_mode);

BOTAN_FFI_EXPORT(3, 6)
int botan_pubkey_load_classic_mceliece(botan_pubkey_t* key,
                                       const uint8_t pubkey[],
                                       size_t key_len,
                                       const char* cmce_mode);

/*
* Algorithm specific key operations: ML-KEM
*/

BOTAN_FFI_EXPORT(3, 6)
int botan_privkey_load_ml_kem(botan_privkey_t* key, const uint8_t privkey[], size_t key_len, const char* mlkem_mode);

BOTAN_FFI_EXPORT(3, 6)
int botan_pubkey_load_ml_kem(botan_pubkey_t* key, const uint8_t pubkey[], size_t key_len, const char* mlkem_mode);

/*
* Algorithm specific key operations: SLH-DSA
*/

BOTAN_FFI_EXPORT(3, 6)
int botan_privkey_load_slh_dsa(botan_privkey_t* key, const uint8_t privkey[], size_t key_len, const char* slhdsa_mode);

BOTAN_FFI_EXPORT(3, 6)
int botan_pubkey_load_slh_dsa(botan_pubkey_t* key, const uint8_t pubkey[], size_t key_len, const char* slhdsa_mode);

/*
* Algorithm specific key operations: ECDSA and ECDH
*/
BOTAN_FFI_EXPORT(3, 2)
int botan_pubkey_ecc_key_used_explicit_encoding(botan_pubkey_t key);

BOTAN_FFI_EXPORT(2, 2)
int botan_privkey_load_ecdsa(botan_privkey_t* key, botan_mp_t scalar, const char* curve_name);

BOTAN_FFI_EXPORT(2, 2)
int botan_pubkey_load_ecdsa(botan_pubkey_t* key, botan_mp_t public_x, botan_mp_t public_y, const char* curve_name);

BOTAN_FFI_EXPORT(2, 2)
int botan_pubkey_load_ecdh(botan_pubkey_t* key, botan_mp_t public_x, botan_mp_t public_y, const char* curve_name);

BOTAN_FFI_EXPORT(2, 2)
int botan_privkey_load_ecdh(botan_privkey_t* key, botan_mp_t scalar, const char* curve_name);

BOTAN_FFI_EXPORT(2, 2)
int botan_pubkey_load_sm2(botan_pubkey_t* key, botan_mp_t public_x, botan_mp_t public_y, const char* curve_name);

BOTAN_FFI_EXPORT(2, 2)
int botan_privkey_load_sm2(botan_privkey_t* key, botan_mp_t scalar, const char* curve_name);

BOTAN_FFI_DEPRECATED("Use botan_pubkey_load_sm2")
BOTAN_FFI_EXPORT(2, 2)
int botan_pubkey_load_sm2_enc(botan_pubkey_t* key, botan_mp_t public_x, botan_mp_t public_y, const char* curve_name);

BOTAN_FFI_DEPRECATED("Use botan_privkey_load_sm2")
BOTAN_FFI_EXPORT(2, 2)
int botan_privkey_load_sm2_enc(botan_privkey_t* key, botan_mp_t scalar, const char* curve_name);

BOTAN_FFI_EXPORT(2, 3)
int botan_pubkey_sm2_compute_za(
   uint8_t out[], size_t* out_len, const char* ident, const char* hash_algo, botan_pubkey_t key);

/**
* View the uncompressed public point associated with the key
*/
BOTAN_FFI_EXPORT(3, 0)
int botan_pubkey_view_ec_public_point(botan_pubkey_t key, botan_view_ctx ctx, botan_view_bin_fn view);

/*
* Public Key Encryption
*/
typedef struct botan_pk_op_encrypt_struct* botan_pk_op_encrypt_t;

BOTAN_FFI_EXPORT(2, 0)
int botan_pk_op_encrypt_create(botan_pk_op_encrypt_t* op, botan_pubkey_t key, const char* padding, uint32_t flags);

/**
* @return 0 if success, error if invalid object handle
*/
BOTAN_FFI_EXPORT(2, 0) int botan_pk_op_encrypt_destroy(botan_pk_op_encrypt_t op);

BOTAN_FFI_EXPORT(2, 8)
int botan_pk_op_encrypt_output_length(botan_pk_op_encrypt_t op, size_t ptext_len, size_t* ctext_len);

BOTAN_FFI_EXPORT(2, 0)
int botan_pk_op_encrypt(botan_pk_op_encrypt_t op,
                        botan_rng_t rng,
                        uint8_t out[],
                        size_t* out_len,
                        const uint8_t plaintext[],
                        size_t plaintext_len);

/*
* Public Key Decryption
*/
typedef struct botan_pk_op_decrypt_struct* botan_pk_op_decrypt_t;

BOTAN_FFI_EXPORT(2, 0)
int botan_pk_op_decrypt_create(botan_pk_op_decrypt_t* op, botan_privkey_t key, const char* padding, uint32_t flags);

/**
* @return 0 if success, error if invalid object handle
*/
BOTAN_FFI_EXPORT(2, 0) int botan_pk_op_decrypt_destroy(botan_pk_op_decrypt_t op);

BOTAN_FFI_EXPORT(2, 8)
int botan_pk_op_decrypt_output_length(botan_pk_op_decrypt_t op, size_t ctext_len, size_t* ptext_len);

BOTAN_FFI_EXPORT(2, 0)
int botan_pk_op_decrypt(
   botan_pk_op_decrypt_t op, uint8_t out[], size_t* out_len, const uint8_t ciphertext[], size_t ciphertext_len);

/*
* Signature Generation
*/

#define BOTAN_PUBKEY_DER_FORMAT_SIGNATURE 1

typedef struct botan_pk_op_sign_struct* botan_pk_op_sign_t;

BOTAN_FFI_EXPORT(2, 0)
int botan_pk_op_sign_create(botan_pk_op_sign_t* op, botan_privkey_t key, const char* hash_and_padding, uint32_t flags);

/**
* @return 0 if success, error if invalid object handle
*/
BOTAN_FFI_EXPORT(2, 0) int botan_pk_op_sign_destroy(botan_pk_op_sign_t op);

BOTAN_FFI_EXPORT(2, 8) int botan_pk_op_sign_output_length(botan_pk_op_sign_t op, size_t* olen);

BOTAN_FFI_EXPORT(2, 0) int botan_pk_op_sign_update(botan_pk_op_sign_t op, const uint8_t in[], size_t in_len);

BOTAN_FFI_EXPORT(2, 0)
int botan_pk_op_sign_finish(botan_pk_op_sign_t op, botan_rng_t rng, uint8_t sig[], size_t* sig_len);

/*
* Signature Verification
*/
typedef struct botan_pk_op_verify_struct* botan_pk_op_verify_t;

BOTAN_FFI_EXPORT(2, 0)
int botan_pk_op_verify_create(botan_pk_op_verify_t* op,
                              botan_pubkey_t key,
                              const char* hash_and_padding,
                              uint32_t flags);

/**
* @return 0 if success, error if invalid object handle
*/
BOTAN_FFI_EXPORT(2, 0) int botan_pk_op_verify_destroy(botan_pk_op_verify_t op);

BOTAN_FFI_EXPORT(2, 0) int botan_pk_op_verify_update(botan_pk_op_verify_t op, const uint8_t in[], size_t in_len);
BOTAN_FFI_EXPORT(2, 0) int botan_pk_op_verify_finish(botan_pk_op_verify_t op, const uint8_t sig[], size_t sig_len);

/*
* Key Agreement
*/
typedef struct botan_pk_op_ka_struct* botan_pk_op_ka_t;

BOTAN_FFI_EXPORT(2, 0)
int botan_pk_op_key_agreement_create(botan_pk_op_ka_t* op, botan_privkey_t key, const char* kdf, uint32_t flags);

/**
* @return 0 if success, error if invalid object handle
*/
BOTAN_FFI_EXPORT(2, 0) int botan_pk_op_key_agreement_destroy(botan_pk_op_ka_t op);

BOTAN_FFI_EXPORT(2, 0) int botan_pk_op_key_agreement_export_public(botan_privkey_t key, uint8_t out[], size_t* out_len);

BOTAN_FFI_EXPORT(3, 0)
int botan_pk_op_key_agreement_view_public(botan_privkey_t key, botan_view_ctx ctx, botan_view_bin_fn view);

BOTAN_FFI_EXPORT(2, 8) int botan_pk_op_key_agreement_size(botan_pk_op_ka_t op, size_t* out_len);

BOTAN_FFI_EXPORT(2, 0)
int botan_pk_op_key_agreement(botan_pk_op_ka_t op,
                              uint8_t out[],
                              size_t* out_len,
                              const uint8_t other_key[],
                              size_t other_key_len,
                              const uint8_t salt[],
                              size_t salt_len);

/*
* Key Encapsulation
*/
typedef struct botan_pk_op_kem_encrypt_struct* botan_pk_op_kem_encrypt_t;

BOTAN_FFI_EXPORT(3, 0)
int botan_pk_op_kem_encrypt_create(botan_pk_op_kem_encrypt_t* op, botan_pubkey_t key, const char* kdf);

/**
* @return 0 if success, error if invalid object handle
*/
BOTAN_FFI_EXPORT(3, 0) int botan_pk_op_kem_encrypt_destroy(botan_pk_op_kem_encrypt_t op);

BOTAN_FFI_EXPORT(3, 0)
int botan_pk_op_kem_encrypt_shared_key_length(botan_pk_op_kem_encrypt_t op,
                                              size_t desired_shared_key_length,
                                              size_t* output_shared_key_length);

BOTAN_FFI_EXPORT(3, 0)
int botan_pk_op_kem_encrypt_encapsulated_key_length(botan_pk_op_kem_encrypt_t op,
                                                    size_t* output_encapsulated_key_length);

BOTAN_FFI_EXPORT(3, 0)
int botan_pk_op_kem_encrypt_create_shared_key(botan_pk_op_kem_encrypt_t op,
                                              botan_rng_t rng,
                                              const uint8_t salt[],
                                              size_t salt_len,
                                              size_t desired_shared_key_len,
                                              uint8_t shared_key[],
                                              size_t* shared_key_len,
                                              uint8_t encapsulated_key[],
                                              size_t* encapsulated_key_len);

typedef struct botan_pk_op_kem_decrypt_struct* botan_pk_op_kem_decrypt_t;

BOTAN_FFI_EXPORT(3, 0)
int botan_pk_op_kem_decrypt_create(botan_pk_op_kem_decrypt_t* op, botan_privkey_t key, const char* kdf);

/**
* @return 0 if success, error if invalid object handle
*/
BOTAN_FFI_EXPORT(3, 0) int botan_pk_op_kem_decrypt_destroy(botan_pk_op_kem_decrypt_t op);

BOTAN_FFI_EXPORT(3, 0)
int botan_pk_op_kem_decrypt_shared_key_length(botan_pk_op_kem_decrypt_t op,
                                              size_t desired_shared_key_length,
                                              size_t* output_shared_key_length);

BOTAN_FFI_EXPORT(3, 0)
int botan_pk_op_kem_decrypt_shared_key(botan_pk_op_kem_decrypt_t op,
                                       const uint8_t salt[],
                                       size_t salt_len,
                                       const uint8_t encapsulated_key[],
                                       size_t encapsulated_key_len,
                                       size_t desired_shared_key_len,
                                       uint8_t shared_key[],
                                       size_t* shared_key_len);

/**
* Signature Scheme Utility Functions
*/

BOTAN_FFI_EXPORT(2, 0) int botan_pkcs_hash_id(const char* hash_name, uint8_t pkcs_id[], size_t* pkcs_id_len);

/*
* Always returns BOTAN_FFI_ERROR_NOT_IMPLEMENTED
*/
BOTAN_FFI_DEPRECATED("No longer implemented")
BOTAN_FFI_EXPORT(2, 0)
int botan_mceies_encrypt(botan_pubkey_t mce_key,
                         botan_rng_t rng,
                         const char* aead,
                         const uint8_t pt[],
                         size_t pt_len,
                         const uint8_t ad[],
                         size_t ad_len,
                         uint8_t ct[],
                         size_t* ct_len);

/*
* Always returns BOTAN_FFI_ERROR_NOT_IMPLEMENTED
*/
BOTAN_FFI_DEPRECATED("No longer implemented")
BOTAN_FFI_EXPORT(2, 0)
int botan_mceies_decrypt(botan_privkey_t mce_key,
                         const char* aead,
                         const uint8_t ct[],
                         size_t ct_len,
                         const uint8_t ad[],
                         size_t ad_len,
                         uint8_t pt[],
                         size_t* pt_len);

/*
* X.509 certificates
**************************/

typedef struct botan_x509_cert_struct* botan_x509_cert_t;

BOTAN_FFI_EXPORT(2, 0) int botan_x509_cert_load(botan_x509_cert_t* cert_obj, const uint8_t cert[], size_t cert_len);
BOTAN_FFI_EXPORT(2, 0) int botan_x509_cert_load_file(botan_x509_cert_t* cert_obj, const char* filename);

/**
* @return 0 if success, error if invalid object handle
*/
BOTAN_FFI_EXPORT(2, 0) int botan_x509_cert_destroy(botan_x509_cert_t cert);

BOTAN_FFI_EXPORT(2, 8) int botan_x509_cert_dup(botan_x509_cert_t* new_cert, botan_x509_cert_t cert);

/* Prefer botan_x509_cert_not_before and botan_x509_cert_not_after */
BOTAN_FFI_EXPORT(2, 0) int botan_x509_cert_get_time_starts(botan_x509_cert_t cert, char out[], size_t* out_len);
BOTAN_FFI_EXPORT(2, 0) int botan_x509_cert_get_time_expires(botan_x509_cert_t cert, char out[], size_t* out_len);

BOTAN_FFI_EXPORT(2, 8) int botan_x509_cert_not_before(botan_x509_cert_t cert, uint64_t* time_since_epoch);
BOTAN_FFI_EXPORT(2, 8) int botan_x509_cert_not_after(botan_x509_cert_t cert, uint64_t* time_since_epoch);

BOTAN_FFI_EXPORT(2, 0)
int botan_x509_cert_get_fingerprint(botan_x509_cert_t cert, const char* hash, uint8_t out[], size_t* out_len);

BOTAN_FFI_EXPORT(2, 0) int botan_x509_cert_get_serial_number(botan_x509_cert_t cert, uint8_t out[], size_t* out_len);
BOTAN_FFI_EXPORT(2, 0) int botan_x509_cert_get_authority_key_id(botan_x509_cert_t cert, uint8_t out[], size_t* out_len);
BOTAN_FFI_EXPORT(2, 0) int botan_x509_cert_get_subject_key_id(botan_x509_cert_t cert, uint8_t out[], size_t* out_len);

BOTAN_FFI_EXPORT(2, 0) int botan_x509_cert_get_public_key_bits(botan_x509_cert_t cert, uint8_t out[], size_t* out_len);

BOTAN_FFI_EXPORT(3, 0)
int botan_x509_cert_view_public_key_bits(botan_x509_cert_t cert, botan_view_ctx ctx, botan_view_bin_fn view);

BOTAN_FFI_EXPORT(2, 0) int botan_x509_cert_get_public_key(botan_x509_cert_t cert, botan_pubkey_t* key);

BOTAN_FFI_EXPORT(2, 0)
int botan_x509_cert_get_issuer_dn(
   botan_x509_cert_t cert, const char* key, size_t index, uint8_t out[], size_t* out_len);

BOTAN_FFI_EXPORT(2, 0)
int botan_x509_cert_get_subject_dn(
   botan_x509_cert_t cert, const char* key, size_t index, uint8_t out[], size_t* out_len);

BOTAN_FFI_EXPORT(2, 0) int botan_x509_cert_to_string(botan_x509_cert_t cert, char out[], size_t* out_len);

BOTAN_FFI_EXPORT(3, 0)
int botan_x509_cert_view_as_string(botan_x509_cert_t cert, botan_view_ctx ctx, botan_view_str_fn view);

/* Must match values of Key_Constraints in key_constraints.h */
enum botan_x509_cert_key_constraints {
   NO_CONSTRAINTS = 0,
   DIGITAL_SIGNATURE = 32768,
   NON_REPUDIATION = 16384,
   KEY_ENCIPHERMENT = 8192,
   DATA_ENCIPHERMENT = 4096,
   KEY_AGREEMENT = 2048,
   KEY_CERT_SIGN = 1024,
   CRL_SIGN = 512,
   ENCIPHER_ONLY = 256,
   DECIPHER_ONLY = 128
};

BOTAN_FFI_EXPORT(2, 0) int botan_x509_cert_allowed_usage(botan_x509_cert_t cert, unsigned int key_usage);

/**
* Check if the certificate matches the specified hostname via alternative name or CN match.
* RFC 5280 wildcards also supported.
*/
BOTAN_FFI_EXPORT(2, 5) int botan_x509_cert_hostname_match(botan_x509_cert_t cert, const char* hostname);

/**
* Returns 0 if the validation was successful, 1 if validation failed,
* and negative on error. A status code with details is written to
* *validation_result
*
* Intermediates or trusted lists can be null
* Trusted path can be null
*/
BOTAN_FFI_EXPORT(2, 8)
int botan_x509_cert_verify(int* validation_result,
                           botan_x509_cert_t cert,
                           const botan_x509_cert_t* intermediates,
                           size_t intermediates_len,
                           const botan_x509_cert_t* trusted,
                           size_t trusted_len,
                           const char* trusted_path,
                           size_t required_strength,
                           const char* hostname,
                           uint64_t reference_time);

/**
* Returns a pointer to a static character string explaining the status code,
* or else NULL if unknown.
*/
BOTAN_FFI_EXPORT(2, 8) const char* botan_x509_cert_validation_status(int code);

/*
* X.509 CRL
**************************/

typedef struct botan_x509_crl_struct* botan_x509_crl_t;

BOTAN_FFI_EXPORT(2, 13) int botan_x509_crl_load_file(botan_x509_crl_t* crl_obj, const char* crl_path);
BOTAN_FFI_EXPORT(2, 13)
int botan_x509_crl_load(botan_x509_crl_t* crl_obj, const uint8_t crl_bits[], size_t crl_bits_len);

BOTAN_FFI_EXPORT(2, 13) int botan_x509_crl_destroy(botan_x509_crl_t crl);

/**
 * Given a CRL and a certificate,
 * check if the certificate is revoked on that particular CRL
 */
BOTAN_FFI_EXPORT(2, 13) int botan_x509_is_revoked(botan_x509_crl_t crl, botan_x509_cert_t cert);

/**
 * Different flavor of `botan_x509_cert_verify`, supports revocation lists.
 * CRLs are passed as an array, same as intermediates and trusted CAs
 */
BOTAN_FFI_EXPORT(2, 13)
int botan_x509_cert_verify_with_crl(int* validation_result,
                                    botan_x509_cert_t cert,
                                    const botan_x509_cert_t* intermediates,
                                    size_t intermediates_len,
                                    const botan_x509_cert_t* trusted,
                                    size_t trusted_len,
                                    const botan_x509_crl_t* crls,
                                    size_t crls_len,
                                    const char* trusted_path,
                                    size_t required_strength,
                                    const char* hostname,
                                    uint64_t reference_time);

/**
 * Key wrapping as per RFC 3394
 */
BOTAN_FFI_DEPRECATED("Use botan_nist_kw_enc")
BOTAN_FFI_EXPORT(2, 2)
int botan_key_wrap3394(const uint8_t key[],
                       size_t key_len,
                       const uint8_t kek[],
                       size_t kek_len,
                       uint8_t wrapped_key[],
                       size_t* wrapped_key_len);

BOTAN_FFI_DEPRECATED("Use botan_nist_kw_dec")
BOTAN_FFI_EXPORT(2, 2)
int botan_key_unwrap3394(const uint8_t wrapped_key[],
                         size_t wrapped_key_len,
                         const uint8_t kek[],
                         size_t kek_len,
                         uint8_t key[],
                         size_t* key_len);

BOTAN_FFI_EXPORT(3, 0)
int botan_nist_kw_enc(const char* cipher_algo,
                      int padded,
                      const uint8_t key[],
                      size_t key_len,
                      const uint8_t kek[],
                      size_t kek_len,
                      uint8_t wrapped_key[],
                      size_t* wrapped_key_len);

BOTAN_FFI_EXPORT(3, 0)
int botan_nist_kw_dec(const char* cipher_algo,
                      int padded,
                      const uint8_t wrapped_key[],
                      size_t wrapped_key_len,
                      const uint8_t kek[],
                      size_t kek_len,
                      uint8_t key[],
                      size_t* key_len);

/**
* HOTP
*/

typedef struct botan_hotp_struct* botan_hotp_t;

/**
* Initialize a HOTP instance
*/
BOTAN_FFI_EXPORT(2, 8)
int botan_hotp_init(botan_hotp_t* hotp, const uint8_t key[], size_t key_len, const char* hash_algo, size_t digits);

/**
* Destroy a HOTP instance
* @return 0 if success, error if invalid object handle
*/
BOTAN_FFI_EXPORT(2, 8)
int botan_hotp_destroy(botan_hotp_t hotp);

/**
* Generate a HOTP code for the provided counter
*/
BOTAN_FFI_EXPORT(2, 8)
int botan_hotp_generate(botan_hotp_t hotp, uint32_t* hotp_code, uint64_t hotp_counter);

/**
* Verify a HOTP code
*/
BOTAN_FFI_EXPORT(2, 8)
int botan_hotp_check(
   botan_hotp_t hotp, uint64_t* next_hotp_counter, uint32_t hotp_code, uint64_t hotp_counter, size_t resync_range);

/**
* TOTP
*/

typedef struct botan_totp_struct* botan_totp_t;

/**
* Initialize a TOTP instance
*/
BOTAN_FFI_EXPORT(2, 8)
int botan_totp_init(
   botan_totp_t* totp, const uint8_t key[], size_t key_len, const char* hash_algo, size_t digits, size_t time_step);

/**
* Destroy a TOTP instance
* @return 0 if success, error if invalid object handle
*/
BOTAN_FFI_EXPORT(2, 8)
int botan_totp_destroy(botan_totp_t totp);

/**
* Generate a TOTP code for the provided timestamp
* @param totp the TOTP object
* @param totp_code the OTP code will be written here
* @param timestamp the current local timestamp
*/
BOTAN_FFI_EXPORT(2, 8)
int botan_totp_generate(botan_totp_t totp, uint32_t* totp_code, uint64_t timestamp);

/**
* Verify a TOTP code
* @param totp the TOTP object
* @param totp_code the presented OTP
* @param timestamp the current local timestamp
* @param acceptable_clock_drift specifies the acceptable amount
* of clock drift (in terms of time steps) between the two hosts.
*/
BOTAN_FFI_EXPORT(2, 8)
int botan_totp_check(botan_totp_t totp, uint32_t totp_code, uint64_t timestamp, size_t acceptable_clock_drift);

/**
* Format Preserving Encryption
*/

typedef struct botan_fpe_struct* botan_fpe_t;

#define BOTAN_FPE_FLAG_FE1_COMPAT_MODE 1

BOTAN_FFI_EXPORT(2, 8)
int botan_fpe_fe1_init(
   botan_fpe_t* fpe, botan_mp_t n, const uint8_t key[], size_t key_len, size_t rounds, uint32_t flags);

/**
* @return 0 if success, error if invalid object handle
*/
BOTAN_FFI_EXPORT(2, 8)
int botan_fpe_destroy(botan_fpe_t fpe);

BOTAN_FFI_EXPORT(2, 8)
int botan_fpe_encrypt(botan_fpe_t fpe, botan_mp_t x, const uint8_t tweak[], size_t tweak_len);

BOTAN_FFI_EXPORT(2, 8)
int botan_fpe_decrypt(botan_fpe_t fpe, botan_mp_t x, const uint8_t tweak[], size_t tweak_len);

/**
* SRP-6 Server Session type
*/
typedef struct botan_srp6_server_session_struct* botan_srp6_server_session_t;

/**
* Initialize an SRP-6 server session object
* @param srp6 SRP-6 server session object
*/
BOTAN_FFI_EXPORT(3, 0)
int botan_srp6_server_session_init(botan_srp6_server_session_t* srp6);

/**
* Frees all resources of the SRP-6 server session object
* @param srp6 SRP-6 server session object
* @return 0 if success, error if invalid object handle
*/
BOTAN_FFI_EXPORT(3, 0)
int botan_srp6_server_session_destroy(botan_srp6_server_session_t srp6);

/**
* SRP-6 Server side step 1
* @param srp6 SRP-6 server session object
* @param verifier the verification value saved from client registration
* @param verifier_len SRP-6 verifier value length
* @param group_id the SRP group id
* @param hash_id the SRP hash in use
* @param rng_obj a random number generator object
* @param B_pub out buffer to store the SRP-6 B value
* @param B_pub_len SRP-6 B value length
* @return 0 on success, negative on failure
*/
BOTAN_FFI_EXPORT(3, 0)
int botan_srp6_server_session_step1(botan_srp6_server_session_t srp6,
                                    const uint8_t verifier[],
                                    size_t verifier_len,
                                    const char* group_id,
                                    const char* hash_id,
                                    botan_rng_t rng_obj,
                                    uint8_t B_pub[],
                                    size_t* B_pub_len);

/**
* SRP-6 Server side step 2
* @param srp6 SRP-6 server session object
* @param A the client's value
* @param A_len the client's value length
* @param key out buffer to store the symmetric key value
* @param key_len symmetric key length
* @return 0 on success, negative on failure
*/
BOTAN_FFI_EXPORT(3, 0)
int botan_srp6_server_session_step2(
   botan_srp6_server_session_t srp6, const uint8_t A[], size_t A_len, uint8_t key[], size_t* key_len);

/**
* Generate a new SRP-6 verifier
* @param identifier a username or other client identifier
* @param password the secret used to authenticate user
* @param salt a randomly chosen value, at least 128 bits long
* @param salt_len the length of salt
* @param group_id specifies the shared SRP group
* @param hash_id specifies a secure hash function
* @param verifier out buffer to store the SRP-6 verifier value
* @param verifier_len SRP-6 verifier value length
* @return 0 on success, negative on failure
*/
BOTAN_FFI_EXPORT(3, 0)
int botan_srp6_generate_verifier(const char* identifier,
                                 const char* password,
                                 const uint8_t salt[],
                                 size_t salt_len,
                                 const char* group_id,
                                 const char* hash_id,
                                 uint8_t verifier[],
                                 size_t* verifier_len);

/**
* SRP6a Client side
* @param username the username we are attempting login for
* @param password the password we are attempting to use
* @param group_id specifies the shared SRP group
* @param hash_id specifies a secure hash function
* @param salt is the salt value sent by the server
* @param salt_len the length of salt
* @param B is the server's public value
* @param B_len is the server's public value length
* @param rng_obj is a random number generator object
* @param A out buffer to store the SRP-6 A value
* @param A_len SRP-6 A verifier value length
* @param K out buffer to store the symmetric value
* @param K_len symmetric key length
* @return 0 on success, negative on failure
*/
BOTAN_FFI_EXPORT(3, 0)
int botan_srp6_client_agree(const char* username,
                            const char* password,
                            const char* group_id,
                            const char* hash_id,
                            const uint8_t salt[],
                            size_t salt_len,
                            const uint8_t B[],
                            size_t B_len,
                            botan_rng_t rng_obj,
                            uint8_t A[],
                            size_t* A_len,
                            uint8_t K[],
                            size_t* K_len);

/**
* Return the size, in bytes, of the prime associated with group_id
*/
BOTAN_FFI_EXPORT(3, 0)
int botan_srp6_group_size(const char* group_id, size_t* group_p_bytes);

/**
 * ZFEC
 */

/**
 * Encode some bytes with certain ZFEC parameters.
 *
 * @param K the number of shares needed for recovery
 * @param N the number of shares generated
 * @param input the data to FEC
 * @param size the length in bytes of input, which must be a multiple of K
 *
 * @param outputs An out parameter pointing to a fully allocated array of size
 *                [N][size / K].  For all n in range, an encoded block will be
 *                written to the memory starting at outputs[n][0].
 *
 * @return 0 on success, negative on failure
 */
BOTAN_FFI_EXPORT(3, 0)
int botan_zfec_encode(size_t K, size_t N, const uint8_t* input, size_t size, uint8_t** outputs);

/**
 * Decode some previously encoded shares using certain ZFEC parameters.
 *
 * @param K the number of shares needed for recovery
 * @param N the total number of shares
 *
 * @param indexes The index into the encoder's outputs for the corresponding
 *                element of the inputs array. Must be of length K.
 *
 * @param inputs K previously encoded shares to decode
 * @param shareSize the length in bytes of each input
 *
 * @param outputs An out parameter pointing to a fully allocated array of size
 *                [K][shareSize].  For all k in range, a decoded block will
 *                written to the memory starting at outputs[k][0].
 *
 * @return 0 on success, negative on failure
 */
BOTAN_FFI_EXPORT(3, 0)
int botan_zfec_decode(
   size_t K, size_t N, const size_t* indexes, uint8_t* const* inputs, size_t shareSize, uint8_t** outputs);

/**
* TPM2 context
*/
typedef struct botan_tpm2_ctx_struct* botan_tpm2_ctx_t;

/**
* TPM2 session
*/
typedef struct botan_tpm2_session_struct* botan_tpm2_session_t;

/**
* TPM2 crypto backend state object
*/
typedef struct botan_tpm2_crypto_backend_state_struct* botan_tpm2_crypto_backend_state_t;

struct ESYS_CONTEXT;

/**
* Checks if Botan's TSS2 crypto backend can be used in this build
* @returns 1 if the crypto backend can be enabled
*/
BOTAN_FFI_EXPORT(3, 6)
int botan_tpm2_supports_crypto_backend();

/**
* Initialize a TPM2 context
* @param ctx_out output TPM2 context
* @param tcti_nameconf TCTI config (may be nullptr)
* @return 0 on success
*/
BOTAN_FFI_EXPORT(3, 6) int botan_tpm2_ctx_init(botan_tpm2_ctx_t* ctx_out, const char* tcti_nameconf);

/**
* Initialize a TPM2 context
* @param ctx_out output TPM2 context
* @param tcti_name TCTI name (may be nullptr)
* @param tcti_conf TCTI config (may be nullptr)
* @return 0 on success
*/
BOTAN_FFI_EXPORT(3, 6)
int botan_tpm2_ctx_init_ex(botan_tpm2_ctx_t* ctx_out, const char* tcti_name, const char* tcti_conf);

/**
* Wrap an existing ESYS_CONTEXT for use in Botan.
* Note that destroying the created botan_tpm2_ctx_t won't
* finalize @p esys_ctx
* @param ctx_out output TPM2 context
* @param esys_ctx ESYS_CONTEXT to wrap
* @return 0 on success
*/
BOTAN_FFI_EXPORT(3, 7)
int botan_tpm2_ctx_from_esys(botan_tpm2_ctx_t* ctx_out, struct ESYS_CONTEXT* esys_ctx);

/**
* Enable Botan's TSS2 crypto backend that replaces the cryptographic functions
* required for the communication with the TPM with implementations provided
* by Botan instead of using TSS' defaults OpenSSL or mbedTLS.
* Note that the provided @p rng should not be dependent on the TPM and the
* caller must ensure that it remains usable for the lifetime of the @p ctx.
* @param ctx TPM2 context
* @param rng random number generator to be used by the crypto backend
*/
BOTAN_FFI_EXPORT(3, 6)
int botan_tpm2_ctx_enable_crypto_backend(botan_tpm2_ctx_t ctx, botan_rng_t rng);

/**
* Frees all resouces of a TPM2 context
* @param ctx TPM2 context
* @return 0 on success
*/
BOTAN_FFI_EXPORT(3, 6) int botan_tpm2_ctx_destroy(botan_tpm2_ctx_t ctx);

/**
* Use this if you just need Botan's crypto backend but do not want to wrap any
* other ESYS functionality using Botan's TPM2 wrapper.
* A Crypto Backend State is created that the user needs to keep alive for as
* long as the crypto backend is used and needs to be destroyed after.
* Note that the provided @p rng should not be dependent on the TPM and the
* caller must ensure that it remains usable for the lifetime of the @p esys_ctx.
* @param cbs_out To be created Crypto Backend State
* @param esys_ctx TPM2 context
* @param rng random number generator to be used by the crypto backend
*/
BOTAN_FFI_EXPORT(3, 7)
int botan_tpm2_enable_crypto_backend(botan_tpm2_crypto_backend_state_t* cbs_out,
                                     struct ESYS_CONTEXT* esys_ctx,
                                     botan_rng_t rng);

/**
* Frees all resouces of a TPM2 Crypto Callback State
* Note that this does not attempt to de-register the crypto backend,
* it just frees the resource pointed to by @p cbs. Use the ESAPI function
* ``Esys_SetCryptoCallbacks(ctx, nullptr)`` to deregister manually.
* @param cbs TPM2 Crypto Callback State
* @return 0 on success
*/
BOTAN_FFI_EXPORT(3, 7) int botan_tpm2_crypto_backend_state_destroy(botan_tpm2_crypto_backend_state_t cbs);

/**
* Initialize a random number generator object via TPM2
* @param rng_out rng object to create
* @param ctx TPM2 context
* @param s1 the first session to use (optional, may be nullptr)
* @param s2 the second session to use (optional, may be nullptr)
* @param s3 the third session to use (optional, may be nullptr)
*/
BOTAN_FFI_EXPORT(3, 6)
int botan_tpm2_rng_init(botan_rng_t* rng_out,
                        botan_tpm2_ctx_t ctx,
                        botan_tpm2_session_t s1,
                        botan_tpm2_session_t s2,
                        botan_tpm2_session_t s3);

/**
* Create an unauthenticated session for use with TPM2
* @param session_out the session object to create
* @param ctx TPM2 context
*/
BOTAN_FFI_EXPORT(3, 6)
int botan_tpm2_unauthenticated_session_init(botan_tpm2_session_t* session_out, botan_tpm2_ctx_t ctx);

/**
* Create an unauthenticated session for use with TPM2
* @param session the session object to destroy
*/
BOTAN_FFI_EXPORT(3, 6)
int botan_tpm2_session_destroy(botan_tpm2_session_t session);

#ifdef __cplusplus
}
#endif

#endif
