Function esp_idf_svc::sys::mbedtls_rsa_rsassa_pss_sign

pub unsafe extern "C" fn mbedtls_rsa_rsassa_pss_sign(
    ctx: *mut mbedtls_rsa_context,
    f_rng: Option<unsafe extern "C" fn(_: *mut c_void, _: *mut u8, _: usize) -> i32>,
    p_rng: *mut c_void,
    md_alg: u32,
    hashlen: u32,
    hash: *const u8,
    sig: *mut u8,
) -> i32

\brief This function performs a PKCS#1 v2.1 PSS signature operation (RSASSA-PSS-SIGN).

\note The \c hash_id set in \p ctx by calling mbedtls_rsa_set_padding() selects the hash used for the encoding operation and for the mask generation function (MGF1). For more details on the encoding operation and the mask generation function, consult RFC-3447: Public-Key Cryptography Standards (PKCS) #1 v2.1: RSA Cryptography Specifications.

\note This function always uses the maximum possible salt size, up to the length of the payload hash. This choice of salt size complies with FIPS 186-4 §5.5 (e) and RFC 8017 (PKCS#1 v2.2) §9.1.1 step 3. Furthermore this function enforces a minimum salt size which is the hash size minus 2 bytes. If this minimum size is too large given the key size (the salt size, plus the hash size, plus 2 bytes must be no more than the key size in bytes), this function returns #MBEDTLS_ERR_RSA_BAD_INPUT_DATA.

\param ctx The initialized RSA context to use. \param f_rng The RNG function. It is mandatory and must not be \c NULL. \param p_rng The RNG context to be passed to \p f_rng. This may be \c NULL if \p f_rng doesn’t need a context argument. \param md_alg The message-digest algorithm used to hash the original data. Use #MBEDTLS_MD_NONE for signing raw data. \param hashlen The length of the message digest or raw data in Bytes. If \p md_alg is not #MBEDTLS_MD_NONE, this must match the output length of the corresponding hash algorithm. \param hash The buffer holding the message digest or raw data. This must be a readable buffer of at least \p hashlen Bytes. \param sig The buffer to hold the signature. This must be a writable buffer of length \c ctx->len Bytes. For example, \c 256 Bytes for an 2048-bit RSA modulus. A buffer length of #MBEDTLS_MPI_MAX_SIZE is always safe.

\return \c 0 if the signing operation was successful. \return An \c MBEDTLS_ERR_RSA_XXX error code on failure.