/**
 * Copyright (c) 2019 - 2020, Nordic Semiconductor ASA
 *
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice, this
 *    list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form, except as embedded into a Nordic
 *    Semiconductor ASA integrated circuit in a product or a software update for
 *    such product, must reproduce the above copyright notice, this list of
 *    conditions and the following disclaimer in the documentation and/or other
 *    materials provided with the distribution.
 *
 * 3. Neither the name of Nordic Semiconductor ASA nor the names of its
 *    contributors may be used to endorse or promote products derived from this
 *    software without specific prior written permission.
 *
 * 4. This software, with or without modification, must only be used with a
 *    Nordic Semiconductor ASA integrated circuit.
 *
 * 5. Any software provided in binary form under this license must not be reverse
 *    engineered, decompiled, modified and/or disassembled.
 *
 * THIS SOFTWARE IS PROVIDED BY NORDIC SEMICONDUCTOR ASA "AS IS" AND ANY EXPRESS
 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY, NONINFRINGEMENT, AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL NORDIC SEMICONDUCTOR ASA OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
 * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */

/**@file
 * @defgroup nrf_oberon_rsa RSA - Rivest-Shamir-Adleman algorithm
 * @ingroup nrf_oberon
 * @{
 * @brief RSA is a number theoretic public-key encryption and signature algorithm.
 * @}
 * @defgroup nrf_oberon_rsa_api RSA APIs
 * @ingroup nrf_oberon_rsa
 * @{
 * @brief APIs to for RSA encryption/decryption and sign/verify using PKCS1 v1.5, OEAP and PSS.
 *
 * These functions support RSA encryption and signatures with 1024 and 2048-bit
 * modulo and PKCS1 V1.5 padding.
 */

#ifndef OCRYPTO_RSA_H
#define OCRYPTO_RSA_H

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

#include "ocrypto_rsa_key.h"

#ifdef __cplusplus
extern "C" {
#endif

/**@name 1024-bit RSA Functions.
 *
 * This group of functions is used for 1024-bit RSA.
 */
/**@{*/
/**
 * 1024 bit RSA PKCS1 V1.5 encryption.
 *
 * The message @p m is encrypted to a ciphertext returned in @p c.
 *
 * @param[out] c         The generated 128-byte ciphertext.
 * @param      m         The message to be encrypted.
 * @param      mlen      Length of @p m. 0 <= mlen <= 117.
 * @param      seed      The random seed to be used for the padding.
 * @param      slen      Length of @p seed. @p slen >= 125 - @p mlen.
 * @param      pk        A valid 1024-bit RSA public key.
 *
 * @retval -1 If the message is too long (mlen > 117).
 * @retval -2 If the seed is too short (slen < 125 - mlen).
 * @retval 0  Otherwise.
 *
 * @remark The key @p pk should be initialized with @c ocrypto_rsa1024_init_pub_key.
 * @remark The @p seed should consist of non-zero random bytes.
 * @remark @p c and @p m can point to the same address.
 */
int ocrypto_rsa1024_pkcs1_v15_encrypt(
    uint8_t c[128],
    const uint8_t *m, size_t mlen,
    const uint8_t *seed, size_t slen,
    const ocrypto_rsa1024_pub_key *pk);

/**
 * 1024-bit RSA PKCS1 V1.5 decryption.
 *
 * The ciphertext @p c is decrypted to the message returned in @p m.
 *
 * @param[out] m       The decrypted message. The buffer must be long enough to hold the message.
 * @param      mlen    Length of @p m.
 * @param      c       The 128-byte ciphertext to decrypt.
 * @param      k       A valid 1024-bit RSA secret key.
 *
 * @retval -1 If decryption failed.
 * @retval -2 If the output buffer is too short (mlen < length of message).
 * @retval  n If a message of length n was successfully decrypted.
 *
 * @remark The key @p k should be initialized with @c ocrypto_rsa1024_init_key.
 * @remark @p m and @p c can point to the same address.
 */
int ocrypto_rsa1024_pkcs1_v15_decrypt(
    uint8_t *m, size_t mlen,
    const uint8_t c[128],
    const ocrypto_rsa1024_key *k);

/**
 * 1024-bit RSA PKCS1 V1.5 decryption with CRT acceleration.
 *
 * The ciphertext @p c is decrypted to the message returned in @p m.
 *
 * @param[out] m       The decrypted message. The buffer must be long enough to hold the message.
 * @param      mlen    Length of @p m.
 * @param      c       The 128-byte ciphertext to decrypt.
 * @param      k       A valid 1024-bit RSA secret key with CRT coefficients.
 *
 * @retval -1  If decryption failed.
 * @retval -2  If the output buffer is too short (mlen < length of message).
 * @retval  n  If a message of length n was successfully decrypted.
 *
 * @remark The key @p k should be initialized with @c ocrypto_rsa1024_init_crt_key.
 * @remark @p m and @p c can point to the same address.
 */
int ocrypto_rsa1024_pkcs1_v15_crt_decrypt(
    uint8_t *m, size_t mlen,
    const uint8_t c[128],
    const ocrypto_rsa1024_crt_key *k);

/**
 * 1024-bit RSA OAEP SHA256 encryption.
 *
 * The message @p m is encrypted to a ciphertext returned in @p c.
 *
 * @param[out] c         The generated 128-byte ciphertext.
 * @param      m         The message to be encrypted.
 * @param      mlen      Length of @p m. 0 <= mlen <= 62.
 * @param      label     The label associated with the message.
 * @param      llen      Length of @p label. May be 0.
 * @param      seed      32-byte random seed.
 * @param      pk        A valid 1024-bit RSA public key.
 *
 * @retval -1 If the message is too long (mlen > 62).
 * @retval 0  Otherwise.
 *
 * @remark The key @p pk should be initialized with @c ocrypto_rsa1024_init_pub_key.
 * @remark @p c and @p m can point to the same address.
 */
int ocrypto_rsa1024_oaep_sha256_encrypt(
    uint8_t c[128],
    const uint8_t *m, size_t mlen,
    const uint8_t *label, size_t llen,
    const uint8_t seed[32],
    const ocrypto_rsa1024_pub_key *pk);

/**
 * 1024-bit RSA OAEP SHA256 decryption.
 *
 * The ciphertext @p c is decrypted to the message returned in @p m.
 *
 * @param[out] m       The decrypted message. The buffer must be long enough to hold the message.
 * @param      mlen    Length of @p m.
 * @param      c       The 128-byte ciphertext to decrypt.
 * @param      label   The label associated with the message.
 * @param      llen    Length of @p label. May be 0.
 * @param      k       A valid 1024-bit RSA secret key.
 *
 * @retval -1 If decryption failed.
 * @retval -2 If the output buffer is too short (mlen < length of message).
 * @retval  n If a message of length n was successfully decrypted.
 *
 * @remark The key @p k should be initialized with @c ocrypto_rsa1024_init_key.
 * @remark @p m and @p c can point to the same address.
 */
int ocrypto_rsa1024_oaep_sha256_decrypt(
    uint8_t *m, size_t mlen,
    const uint8_t c[128],
    const uint8_t *label, size_t llen,
    const ocrypto_rsa1024_key *k);

/**
 * 1024-bit RSA OAEP SHA256 decryption with CRT acceleration.
 *
 * The ciphertext @p c is decrypted to the message returned in @p m.
 *
 * @param[out] m       The decrypted message. The buffer must be long enough to hold the message.
 * @param      mlen    Length of @p m.
 * @param      c       The 128-byte ciphertext to decrypt.
 * @param      label   The label associated with the message.
 * @param      llen    Length of @p label. May be 0.
 * @param      k       A valid 1024-bit RSA secret key with CRT coefficients.
 *
 * @retval -1  If decryption failed.
 * @retval -2  If the output buffer is too short (mlen < length of message).
 * @retval  n  If a message of length n was successfully decrypted.
 *
 * @remark The key @p k should be initialized with @c ocrypto_rsa1024_init_crt_key.
 * @remark @p m and @p c can point to the same address.
 */
int ocrypto_rsa1024_oaep_sha256_crt_decrypt(
    uint8_t *m, size_t mlen,
    const uint8_t c[128],
    const uint8_t *label, size_t llen,
    const ocrypto_rsa1024_crt_key *k);

/**
 * 1024-bit RSA PKCS1 V1.5 SHA-256 sign.
 *
 * The message @p m is signed and the signature returned in @p s.
 *
 * @param[out] s       The generated 128-byte signature.
 * @param      m       The message to be signed.
 * @param      mlen    Length of @p m.
 * @param      k       A valid 1024-bit RSA secret key.
 *
 * @return 0
 *
 * @remark The key @p k should be initialized with @c ocrypto_rsa1024_init_key.
 * @remark @p s and @p m can point to the same address.
 */
int ocrypto_rsa1024_pkcs1_v15_sha256_sign(
    uint8_t s[128],
    const uint8_t *m, size_t mlen,
    const ocrypto_rsa1024_key *k);

/**
 * 1024-bit RSA PKCS1 V1.5 SHA-256 sign with CRT acceleration.
 *
 * The message @p m is signed and the signature returned in @p s.
 *
 * @param[out] s       The generated 128-byte signature.
 * @param      m       The message to be signed.
 * @param      mlen    Length of @p m.
 * @param      k       A valid 1024-bit RSA secret key with CRT coefficients.
 *
 * @return 0
 *
 * @remark The key @p k should be initialized with @c ocrypto_rsa1024_init_crt_key.
 * @remark @p s and @p m can point to the same address.
 */
int ocrypto_rsa1024_pkcs1_v15_sha256_crt_sign(
    uint8_t s[128],
    const uint8_t *m, size_t mlen,
    const ocrypto_rsa1024_crt_key *k);

/**
 * 1024-bit RSA PKCS1 V1.5 SHA-256 signature verify.
 *
 * The signature @p s is verified for a valid signature of message @p m.
 *
 * @param s      The 128-byte signature.
 * @param m      The signed message.
 * @param mlen   Length of @p m.
 * @param pk     A valid 1024-bit RSA public key.
 *
 * @retval 0  If the signature is valid.
 * @retval -1 If verification failed.
 *
 * @remark The key @p pk should be initialized with @c ocrypto_rsa1024_init_pub_key.
 */
int ocrypto_rsa1024_pkcs1_v15_sha256_verify(
    const uint8_t s[128],
    const uint8_t *m, size_t mlen,
    const ocrypto_rsa1024_pub_key *pk);

/**
 * 1024-bit RSA PSS SHA-256 sign.
 *
 * The message @p m is signed and the signature returned in @p s.
 *
 * @param[out] s       The generated 128-byte signature.
 * @param      m       The message to be signed.
 * @param      mlen    Length of @p m.
 * @param      salt    The salt to be used.
 * @param      slen    Length of @p salt.
 * @param      k       A valid 1024-bit RSA secret key.
 *
 * @retval -2  If the salt is too long.
 * @retval 0   Otherwise.
 *
 * @remark The key @p k should be initialized with @c ocrypto_rsa1024_init_key.
 * @remark @p s and @p m can point to the same address.
 */
int ocrypto_rsa1024_pss_sha256_sign(
    uint8_t s[128],
    const uint8_t *m, size_t mlen,
    const uint8_t *salt, size_t slen,
    const ocrypto_rsa1024_key *k);

/**
 * 1024-bit RSA PSS SHA-256 sign with CRT acceleration.
 *
 * The message @p m is signed and the signature returned in @p s.
 *
 * @param[out] s       The generated 128-byte signature.
 * @param      m       The message to be signed.
 * @param      mlen    Length of @p m.
 * @param      salt    The salt to be used.
 * @param      slen    Length of @p salt.
 * @param      k       A valid 1024-bit RSA secret key with CRT coefficients.
 *
 * @retval -2  If the salt is too long.
 * @retval 0   Otherwise.
 *
 * @remark The key @p k should be initialized with @c ocrypto_rsa1024_init_crt_key.
 * @remark @p s and @p m can point to the same address.
 */
int ocrypto_rsa1024_pss_sha256_crt_sign(
    uint8_t s[128],
    const uint8_t *m, size_t mlen,
    const uint8_t *salt, size_t slen,
    const ocrypto_rsa1024_crt_key *k);

/**
 * 1024-bit RSA PSS SHA-256 signature verify.
 *
 * The signature @p s is verified for a valid signature of message @p m.
 *
 * @param s      The 128-byte signature.
 * @param m      The signed message.
 * @param mlen   Length of @p m.
 * @param slen   The length of the salt.
 * @param pk     A valid 1024-bit RSA public key.
 *
 * @retval 0   If the signature is valid.
 * @retval -1  If verification failed.
 * @retval -2  If the salt is too long.
 *
 * @remark The key @p pk should be initialized with @c ocrypto_rsa1024_init_pub_key.
 */
int ocrypto_rsa1024_pss_sha256_verify(
    const uint8_t s[128],
    const uint8_t *m, size_t mlen,
    size_t slen, // salt length
    const ocrypto_rsa1024_pub_key *pk);
/**@}*/


/**@name 2048-bit RSA Functions.
 *
 * This group of functions is used for 2048-bit RSA.
 */
/**@{*/
/**
 * 2048-bit RSA PKCS1 V1.5 encryption.
 *
 * The message @p m is encrypted to a ciphertext returned in @p c.
 *
 * @param[out] c         The generated 256-byte ciphertext.
 * @param      m         The message to be encrypted.
 * @param      mlen      Length of @p m. 0 <= @p mlen <= 245.
 * @param      seed      The random seed to be used for the padding.
 * @param      slen      Length of @p seed. @p slen >= 253 - @p mlen.
 * @param      pk        A valid 2048-bit RSA public key.
 *
 * @retval -1 If the message is too long (mlen > 245).
 * @retval -2 If the seed is too short (slen < 253 - mlen).
 * @retval 0  Otherwise.
 *
 * @remark The key @p pk should be initialized with @c ocrypto_rsa2048_init_pub_key.
 * @remark The @p seed should consist of non-zero random bytes.
 * @remark @p c and @p m can point to the same address.
 */
int ocrypto_rsa2048_pkcs1_v15_encrypt(
    uint8_t c[256],
    const uint8_t *m, size_t mlen,
    const uint8_t *seed, size_t slen,
    const ocrypto_rsa2048_pub_key *pk);

/**
 * 2048-bit RSA PKCS1 V1.5 decryption.
 *
 * The ciphertext @p c is decrypted to the message returned in @p m.
 *
 * @param[out] m       The decrypted message. The buffer must be long enough to hold the message.
 * @param      mlen    Length of @p m.
 * @param      c       The 256-byte ciphertext to decrypt.
 * @param      k       A valid 2048-bit RSA secret key.

 * @retval -1 If decryption failed.
 * @retval -2 If the output buffer is too short (mlen < length of message).
 * @retval n  If a message of length n was successfully decrypted.
 *
 * @remark The key @p k should be initialized with @c ocrypto_rsa2048_init_key.
 * @remark @p m and @p c can point to the same address.
 */
int ocrypto_rsa2048_pkcs1_v15_decrypt(
    uint8_t *m, size_t mlen,
    const uint8_t c[256],
    const ocrypto_rsa2048_key *k);

/**
 * 2048-bit RSA PKCS1 V1.5 decryption with CRT acceleration.
 *
 * The ciphertext @p c is decrypted to the message returned in @p m.
 *
 * @param[out] m       The decrypted message. The buffer must be long enough to hold the message.
 * @param      mlen    Length of @p m.
 * @param      c       The 256-byte ciphertext to decrypt.
 * @param      k       A valid 2048-bit RSA secret key with CRT coefficients.

 * @retval -1  If decryption failed.
 * @retval -2  If the output buffer is too short (mlen < length of message).
 * @retval  n  If a message of length n was successfully decrypted.
 *
 * @remark The key @p k should be initialized with @c ocrypto_rsa2048_init_crt_key.
 * @remark @p m and @p c can point to the same address.
 */
int ocrypto_rsa2048_pkcs1_v15_crt_decrypt(
    uint8_t *m, size_t mlen,
    const uint8_t c[256],
    const ocrypto_rsa2048_crt_key *k);

/**
 * 2048-bit RSA OAEP SHA256 encryption.
 *
 * The message @p m is encrypted to a ciphertext returned in @p c.
 *
 * @param[out] c         The generated 256-byte ciphertext.
 * @param      m         The message to be encrypted.
 * @param      mlen      Length of @p m. 0 <= mlen <= 190.
 * @param      label     The label associated with the message.
 * @param      llen      Length of @p label. May be 0.
 * @param      seed      32-byte random seed.
 * @param      pk        A valid 2048-bit RSA public key.
 *
 * @retval -1 If the message is too long (mlen > 190).
 * @retval 0  Otherwise.
 *
 * @remark The key @p pk should be initialized with @c ocrypto_rsa2048_init_pub_key.
 * @remark @p c and @p m can point to the same address.
 */
int ocrypto_rsa2048_oaep_sha256_encrypt(
    uint8_t c[256],
    const uint8_t *m, size_t mlen,
    const uint8_t *label, size_t llen,
    const uint8_t seed[32],
    const ocrypto_rsa2048_pub_key *pk);

/**
 * 2048-bit RSA OAEP SHA256 decryption.
 *
 * The ciphertext @p c is decrypted to the message returned in @p m.
 *
 * @param[out] m       The decrypted message. The buffer must be long enough to hold the message.
 * @param      mlen    Length of @p m.
 * @param      c       The 256-byte ciphertext to decrypt.
 * @param      label   The label associated with the message.
 * @param      llen    Length of @p label. May be 0.
 * @param      k       A valid 2048-bit RSA secret key.
 *
 * @retval -1 If decryption failed.
 * @retval -2 If the output buffer is too short (mlen < length of message).
 * @retval  n If a message of length n was successfully decrypted.
 *
 * @remark The key @p k should be initialized with @c ocrypto_rsa2048_init_key.
 * @remark @p m and @p c can point to the same address.
 */
int ocrypto_rsa2048_oaep_sha256_decrypt(
    uint8_t *m, size_t mlen,
    const uint8_t c[256],
    const uint8_t *label, size_t llen,
    const ocrypto_rsa2048_key *k);

/**
 * 2048-bit RSA OAEP SHA256 decryption with CRT acceleration.
 *
 * The ciphertext @p c is decrypted to the message returned in @p m.
 *
 * @param[out] m       The decrypted message. The buffer must be long enough to hold the message.
 * @param      mlen    Length of @p m.
 * @param      c       The 256-byte ciphertext to decrypt.
 * @param      label   The label associated with the message.
 * @param      llen    Length of @p label. May be 0.
 * @param      k       A valid 2048-bit RSA secret key with CRT coefficients.
 *
 * @retval -1  If decryption failed.
 * @retval -2  If the output buffer is too short (mlen < length of message).
 * @retval  n  If a message of length n was successfully decrypted.
 *
 * @remark The key @p k should be initialized with @c ocrypto_rsa2048_init_crt_key.
 * @remark @p m and @p c can point to the same address.
 */
int ocrypto_rsa2048_oaep_sha256_crt_decrypt(
    uint8_t *m, size_t mlen,
    const uint8_t c[256],
    const uint8_t *label, size_t llen,
    const ocrypto_rsa2048_crt_key *k);

/**
 * 2048-bit RSA PKCS1 V1.5 SHA-256 sign.
 *
 * The message @p m is signed and the signature returned in @p s.
 *
 * @param[out] s       The generated 256-byte signature.
 * @param      m       The message to be signed.
 * @param      mlen    Length of @p m.
 * @param      k       A valid 2048-bit RSA secret key.

 * @returns 0
 *
 * @remark The key @p k should be initialized with @c ocrypto_rsa2048_init_key.
 * @remark @p s and @p m can point to the same address.
 */
int ocrypto_rsa2048_pkcs1_v15_sha256_sign(
    uint8_t s[256],
    const uint8_t *m, size_t mlen,
    const ocrypto_rsa2048_key *k);

/**
 * 2048-bit RSA PKCS1 V1.5 SHA-256 sign with CRT acceleration.
 *
 * The message @p m is signed and the signature returned in @p s.
 *
 * @param[out] s       The generated 256-byte signature.
 * @param      m       The message to be signed.
 * @param      mlen    Length of @p m.
 * @param      k       A valid 2048-bit RSA secret key with CRT coefficients.

 * @returns 0
 *
 * @remark The key @p k should be initialized with @c ocrypto_rsa2048_init_crt_key.
 * @remark @p s and @p m can point to the same address.
 */
int ocrypto_rsa2048_pkcs1_v15_sha256_crt_sign(
    uint8_t s[256],
    const uint8_t *m, size_t mlen,
    const ocrypto_rsa2048_crt_key *k);

/**
 * 2048-bit RSA PKCS1 V1.5 SHA-256 signature verify.
 *
 * The signature @p s is verified for a correct signature of message @p m.
 *
 * @param s      The 256-byte signature.
 * @param m      The signed message.
 * @param mlen   Length of @p m.
 * @param pk     A valid 2048-bit RSA public key.
 *
 * @retval 0  If the signature is valid.
 * @retval -1 If verification failed.
 *
 * @remark The key @p pk should be initialized with @c ocrypto_rsa2048_init_pub_key.
 */
int ocrypto_rsa2048_pkcs1_v15_sha256_verify(
    const uint8_t s[256],
    const uint8_t *m, size_t mlen,
    const ocrypto_rsa2048_pub_key *pk);

/**
 * 2048-bit RSA PSS SHA-256 sign.
 *
 * The message @p m is signed and the signature returned in @p s.
 *
 * @param[out] s       The generated 256-byte signature.
 * @param      m       The message to be signed.
 * @param      mlen    Length of @p m.
 * @param      salt    The salt to be used.
 * @param      slen    Length of @p salt.
 * @param      k       A valid 2048-bit RSA secret key.
 *
 * @retval -2  If the salt is too long.
 * @retval 0   Otherwise.
 *
 * @remark The key @p k should be initialized with @c ocrypto_rsa2048_init_key.
 * @remark @p s and @p m can point to the same address.
 */
int ocrypto_rsa2048_pss_sha256_sign(
    uint8_t s[256],
    const uint8_t *m, size_t mlen,
    const uint8_t *salt, size_t slen,
    const ocrypto_rsa2048_key *k);

/**
 * 2048-bit RSA PSS SHA-256 sign with CRT acceleration.
 *
 * The message @p m is signed and the signature returned in @p s.
 *
 * @param[out] s       The generated 256-byte signature.
 * @param      m       The message to be signed.
 * @param      mlen    Length of @p m.
 * @param      salt    The salt to be used.
 * @param      slen    Length of @p salt.
 * @param      k       A valid 2048-bit RSA secret key with CRT coefficients.
 *
 * @retval -2  If the salt is too long.
 * @retval 0   Otherwise.
 *
 * @remark The key @p k should be initialized with @c ocrypto_rsa2048_init_crt_key.
 * @remark @p s and @p m can point to the same address.
 */
int ocrypto_rsa2048_pss_sha256_crt_sign(
    uint8_t s[256],
    const uint8_t *m, size_t mlen,
    const uint8_t *salt, size_t slen,
    const ocrypto_rsa2048_crt_key *k);

/**
 * 2048-bit RSA PSS SHA-256 signature verify.
 *
 * The signature @p s is verified for a valid signature of message @p m.
 *
 * @param s      The 256-byte signature.
 * @param m      The signed message.
 * @param mlen   Length of @p m.
 * @param slen   The length of the salt.
 * @param pk     A valid 2048-bit RSA public key.
 *
 * @retval 0   If the signature is valid.
 * @retval -1  If verification failed.
 * @retval -2  If the salt is too long.
 *
 * @remark The key @p pk should be initialized with @c ocrypto_rsa2048_init_pub_key.
 */
int ocrypto_rsa2048_pss_sha256_verify(
    const uint8_t s[256],
    const uint8_t *m, size_t mlen,
    size_t slen, // salt length
    const ocrypto_rsa2048_pub_key *pk);
/**@}*/


#ifdef __cplusplus
}
#endif

#endif /* #ifndef OCRYPTO_RSA_H */

/** @} */
