Implement psa_sign_message and psa_verify_message functions

Signed-off-by: gabor-mezei-arm <gabor.mezei@arm.com>
diff --git a/include/psa/crypto.h b/include/psa/crypto.h
index 94b8f99..478c0c0 100644
--- a/include/psa/crypto.h
+++ b/include/psa/crypto.h
@@ -2890,6 +2890,123 @@
  */
 
 /**
+ * \brief Sign a message with a private key. For hash-and-sign algorithms,
+ *        this includes the hashing step.
+ *
+ * \note To perform a multi-part hash-and-sign signature algorithm, first use
+ *       a multi-part hash operation and then pass the resulting hash to
+ *       psa_sign_hash(). PSA_ALG_GET_HASH(\p alg) can be used to determine the
+ *       hash algorithm to use.
+ *
+ * \param[in] key               Identifier of the key to use for the operation.
+ *                              It must be an asymmetric key pair. The key must
+ *                              allow the usage #PSA_KEY_USAGE_SIGN_MESSAGE.
+ * \param[in] alg               An asymmetric signature algorithm (PSA_ALG_XXX
+ *                              value such that #PSA_ALG_IS_SIGN_MESSAGE(\p alg)
+ *                              is true), that is compatible with the type of
+ *                              \p key.
+ * \param[in] input             The input message to sign.
+ * \param[in] input_length      Size of the \p input buffer in bytes.
+ * \param[out] signature        Buffer where the signature is to be written.
+ * \param[in] signature_size    Size of the \p signature buffer in bytes. This
+ *                              must be appropriate for the selected
+ *                              algorithm and key:
+ *                              - The required signature size is
+ *                                #PSA_SIGN_OUTPUT_SIZE(key_type, key_bits, \p alg)
+ *                                where key_type and key_bits are the type and
+ *                                bit-size respectively of key.
+ *                              - #PSA_SIGNATURE_MAX_SIZE evaluates to the
+ *                                maximum signature size of any supported
+ *                                signature algorithm.
+ * \param[out] signature_length On success, the number of bytes that make up
+ *                              the returned signature value.
+ *
+ * \retval #PSA_SUCCESS
+ * \retval #PSA_ERROR_INVALID_HANDLE
+ * \retval #PSA_ERROR_NOT_PERMITTED
+ *         The key does not have the #PSA_KEY_USAGE_SIGN_MESSAGE flag,
+ *         or it does not permit the requested algorithm.
+ * \retval #PSA_ERROR_BUFFER_TOO_SMALL
+ *         The size of the \p signature buffer is too small. You can
+ *         determine a sufficient buffer size by calling
+ *         #PSA_SIGN_OUTPUT_SIZE(\c key_type, \c key_bits, \p alg)
+ *         where \c key_type and \c key_bits are the type and bit-size
+ *         respectively of \p key.
+ * \retval #PSA_ERROR_NOT_SUPPORTED
+ * \retval #PSA_ERROR_INVALID_ARGUMENT
+ * \retval #PSA_ERROR_INSUFFICIENT_MEMORY
+ * \retval #PSA_ERROR_COMMUNICATION_FAILURE
+ * \retval #PSA_ERROR_HARDWARE_FAILURE
+ * \retval #PSA_ERROR_CORRUPTION_DETECTED
+ * \retval #PSA_ERROR_STORAGE_FAILURE
+ * \retval #PSA_ERROR_DATA_CORRUPT
+ * \retval #PSA_ERROR_DATA_INVALID
+ * \retval #PSA_ERROR_INSUFFICIENT_ENTROPY
+ * \retval #PSA_ERROR_BAD_STATE
+ *         The library has not been previously initialized by psa_crypto_init().
+ *         It is implementation-dependent whether a failure to initialize
+ *         results in this error code.
+ */
+psa_status_t psa_sign_message( mbedtls_svc_key_id_t key,
+                               psa_algorithm_t alg,
+                               const uint8_t * input,
+                               size_t input_length,
+                               uint8_t * signature,
+                               size_t signature_size,
+                               size_t * signature_length );
+
+/** \brief Verify the signature of a message with a public key, using
+ *         a hash-and-sign verification algorithm.
+ *
+ * \note To perform a multi-part hash-and-sign signature verification
+ *       algorithm, first use a multi-part hash operation to hash the message
+ *       and then pass the resulting hash to psa_verify_hash().
+ *       PSA_ALG_GET_HASH(\p alg) can be used to determine the hash algorithm
+ *       to use.
+ *
+ * \param[in] key               Identifier of the key to use for the operation.
+ *                              It must be a public key or an asymmetric key
+ *                              pair. The key must allow the usage
+ *                              #PSA_KEY_USAGE_VERIFY_MESSAGE.
+ * \param[in] alg               An asymmetric signature algorithm (PSA_ALG_XXX
+ *                              value such that #PSA_ALG_IS_SIGN_MESSAGE(\p alg)
+ *                              is true), that is compatible with the type of
+ *                              \p key.
+ * \param[in] input             The message whose signature is to be verified.
+ * \param[in] input_length      Size of the \p input buffer in bytes.
+ * \param[out] signature        Buffer containing the signature to verify.
+ * \param[in] signature_length  Size of the \p signature buffer in bytes.
+ *
+ * \retval #PSA_SUCCESS
+ * \retval #PSA_ERROR_INVALID_HANDLE
+ * \retval #PSA_ERROR_NOT_PERMITTED
+ *         The key does not have the #PSA_KEY_USAGE_SIGN_MESSAGE flag,
+ *         or it does not permit the requested algorithm.
+ * \retval #PSA_ERROR_INVALID_SIGNATURE
+ *         The calculation was performed successfully, but the passed signature
+ *         is not a valid signature.
+ * \retval #PSA_ERROR_NOT_SUPPORTED
+ * \retval #PSA_ERROR_INVALID_ARGUMENT
+ * \retval #PSA_ERROR_INSUFFICIENT_MEMORY
+ * \retval #PSA_ERROR_COMMUNICATION_FAILURE
+ * \retval #PSA_ERROR_HARDWARE_FAILURE
+ * \retval #PSA_ERROR_CORRUPTION_DETECTED
+ * \retval #PSA_ERROR_STORAGE_FAILURE
+ * \retval #PSA_ERROR_DATA_CORRUPT
+ * \retval #PSA_ERROR_DATA_INVALID
+ * \retval #PSA_ERROR_BAD_STATE
+ *         The library has not been previously initialized by psa_crypto_init().
+ *         It is implementation-dependent whether a failure to initialize
+ *         results in this error code.
+ */
+psa_status_t psa_verify_message( mbedtls_svc_key_id_t key,
+                                 psa_algorithm_t alg,
+                                 const uint8_t * input,
+                                 size_t input_length,
+                                 const uint8_t * signature,
+                                 size_t signature_length );
+
+/**
  * \brief Sign a hash or short message with a private key.
  *
  * Note that to perform a hash-and-sign signature algorithm, you must
@@ -2942,7 +3059,7 @@
                            size_t *signature_length);
 
 /**
- * \brief Verify the signature a hash or short message using a public key.
+ * \brief Verify the signature of a hash or short message using a public key.
  *
  * Note that to perform a hash-and-sign signature algorithm, you must
  * first calculate the hash by calling psa_hash_setup(), psa_hash_update()