Asymmetric cryptography

Functions
psa_status_t	psa_sign_hash (mbedtls_svc_key_id_t key, psa_algorithm_t alg, const uint8_t *hash, size_t hash_length, uint8_t *signature, size_t signature_size, size_t *signature_length)
	Sign a hash or short message with a private key. More...
psa_status_t	psa_verify_hash (mbedtls_svc_key_id_t key, psa_algorithm_t alg, const uint8_t *hash, size_t hash_length, const uint8_t *signature, size_t signature_length)
	Verify the signature a hash or short message using a public key. More...
psa_status_t	psa_asymmetric_encrypt (mbedtls_svc_key_id_t key, psa_algorithm_t alg, const uint8_t *input, size_t input_length, const uint8_t *salt, size_t salt_length, uint8_t *output, size_t output_size, size_t *output_length)
	Encrypt a short message with a public key. More...
psa_status_t	psa_asymmetric_decrypt (mbedtls_svc_key_id_t key, psa_algorithm_t alg, const uint8_t *input, size_t input_length, const uint8_t *salt, size_t salt_length, uint8_t *output, size_t output_size, size_t *output_length)
	Decrypt a short message with a private key. More...

Detailed Description

Function Documentation

psa_sign_hash()

psa_status_t psa_sign_hash	(	mbedtls_svc_key_id_t	key,
		psa_algorithm_t	alg,
		const uint8_t *	hash,
		size_t	hash_length,
		uint8_t *	signature,
		size_t	signature_size,
		size_t *	signature_length
	)

Sign a hash or short message with a private 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() and psa_hash_finish(). Then pass the resulting hash as the hash parameter to this function. You can use PSA_ALG_SIGN_GET_HASH(alg) to determine the hash algorithm to use.

Parameters

	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_HASH.
	alg	A signature algorithm that is compatible with the type of key.
[in]	hash	The hash or message to sign.
	hash_length	Size of the hash buffer in bytes.
[out]	signature	Buffer where the signature is to be written.
	signature_size	Size of the signature buffer in bytes.
[out]	signature_length	On success, the number of bytes that make up the returned signature value.

Return values

PSA_SUCCESS
PSA_ERROR_INVALID_HANDLE
PSA_ERROR_NOT_PERMITTED
PSA_ERROR_BUFFER_TOO_SMALL	The size of the signature buffer is too small. You can determine a sufficient buffer size by calling PSA_SIGN_OUTPUT_SIZE(key_type, key_bits, alg) where key_type and key_bits are the type and bit-size respectively of key.
PSA_ERROR_NOT_SUPPORTED
PSA_ERROR_INVALID_ARGUMENT
PSA_ERROR_INSUFFICIENT_MEMORY
PSA_ERROR_COMMUNICATION_FAILURE
PSA_ERROR_HARDWARE_FAILURE
PSA_ERROR_CORRUPTION_DETECTED
PSA_ERROR_STORAGE_FAILURE
PSA_ERROR_INSUFFICIENT_ENTROPY
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_verify_hash()

psa_status_t psa_verify_hash	(	mbedtls_svc_key_id_t	key,
		psa_algorithm_t	alg,
		const uint8_t *	hash,
		size_t	hash_length,
		const uint8_t *	signature,
		size_t	signature_length
	)

Verify the signature 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() and psa_hash_finish(). Then pass the resulting hash as the hash parameter to this function. You can use PSA_ALG_SIGN_GET_HASH(alg) to determine the hash algorithm to use.

Parameters

	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_HASH.
	alg	A signature algorithm that is compatible with the type of key.
[in]	hash	The hash or message whose signature is to be verified.
	hash_length	Size of the hash buffer in bytes.
[in]	signature	Buffer containing the signature to verify.
	signature_length	Size of the signature buffer in bytes.

Return values

PSA_SUCCESS	The signature is valid.
PSA_ERROR_INVALID_HANDLE
PSA_ERROR_NOT_PERMITTED
PSA_ERROR_INVALID_SIGNATURE	The calculation was perfomed successfully, but the passed signature is not a valid signature.
PSA_ERROR_NOT_SUPPORTED
PSA_ERROR_INVALID_ARGUMENT
PSA_ERROR_INSUFFICIENT_MEMORY
PSA_ERROR_COMMUNICATION_FAILURE
PSA_ERROR_HARDWARE_FAILURE
PSA_ERROR_CORRUPTION_DETECTED
PSA_ERROR_STORAGE_FAILURE
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_asymmetric_encrypt()

psa_status_t psa_asymmetric_encrypt	(	mbedtls_svc_key_id_t	key,
		psa_algorithm_t	alg,
		const uint8_t *	input,
		size_t	input_length,
		const uint8_t *	salt,
		size_t	salt_length,
		uint8_t *	output,
		size_t	output_size,
		size_t *	output_length
	)

Encrypt a short message with a public key.

Parameters

	key	Identifer of the key to use for the operation. It must be a public key or an asymmetric key pair. It must allow the usage PSA_KEY_USAGE_ENCRYPT.
	alg	An asymmetric encryption algorithm that is compatible with the type of key.
[in]	input	The message to encrypt.
	input_length	Size of the input buffer in bytes.
[in]	salt	A salt or label, if supported by the encryption algorithm. If the algorithm does not support a salt, pass NULL. If the algorithm supports an optional salt and you do not want to pass a salt, pass NULL.

• For PSA_ALG_RSA_PKCS1V15_CRYPT, no salt is supported.

  Parameters

  	salt_length	Size of the salt buffer in bytes. If salt is NULL, pass 0.
  [out]	output	Buffer where the encrypted message is to be written.
  	output_size	Size of the output buffer in bytes.
  [out]	output_length	On success, the number of bytes that make up the returned output.

  Return values

  PSA_SUCCESS
  PSA_ERROR_INVALID_HANDLE
  PSA_ERROR_NOT_PERMITTED
  PSA_ERROR_BUFFER_TOO_SMALL	The size of the output buffer is too small. You can determine a sufficient buffer size by calling PSA_ASYMMETRIC_ENCRYPT_OUTPUT_SIZE(key_type, key_bits, alg) where key_type and key_bits are the type and bit-size respectively of key.
  PSA_ERROR_NOT_SUPPORTED
  PSA_ERROR_INVALID_ARGUMENT
  PSA_ERROR_INSUFFICIENT_MEMORY
  PSA_ERROR_COMMUNICATION_FAILURE
  PSA_ERROR_HARDWARE_FAILURE
  PSA_ERROR_CORRUPTION_DETECTED
  PSA_ERROR_STORAGE_FAILURE
  PSA_ERROR_INSUFFICIENT_ENTROPY
  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_asymmetric_decrypt()

psa_status_t psa_asymmetric_decrypt	(	mbedtls_svc_key_id_t	key,
		psa_algorithm_t	alg,
		const uint8_t *	input,
		size_t	input_length,
		const uint8_t *	salt,
		size_t	salt_length,
		uint8_t *	output,
		size_t	output_size,
		size_t *	output_length
	)

Decrypt a short message with a private key.

Parameters

	key	Identifier of the key to use for the operation. It must be an asymmetric key pair. It must allow the usage PSA_KEY_USAGE_DECRYPT.
	alg	An asymmetric encryption algorithm that is compatible with the type of key.
[in]	input	The message to decrypt.
	input_length	Size of the input buffer in bytes.
[in]	salt	A salt or label, if supported by the encryption algorithm. If the algorithm does not support a salt, pass NULL. If the algorithm supports an optional salt and you do not want to pass a salt, pass NULL.

• For PSA_ALG_RSA_PKCS1V15_CRYPT, no salt is supported.

  Parameters

  	salt_length	Size of the salt buffer in bytes. If salt is NULL, pass 0.
  [out]	output	Buffer where the decrypted message is to be written.
  	output_size	Size of the output buffer in bytes.
  [out]	output_length	On success, the number of bytes that make up the returned output.

  Return values

  PSA_SUCCESS
  PSA_ERROR_INVALID_HANDLE
  PSA_ERROR_NOT_PERMITTED
  PSA_ERROR_BUFFER_TOO_SMALL	The size of the output buffer is too small. You can determine a sufficient buffer size by calling PSA_ASYMMETRIC_DECRYPT_OUTPUT_SIZE(key_type, key_bits, alg) where key_type and key_bits are the type and bit-size respectively of key.
  PSA_ERROR_NOT_SUPPORTED
  PSA_ERROR_INVALID_ARGUMENT
  PSA_ERROR_INSUFFICIENT_MEMORY
  PSA_ERROR_COMMUNICATION_FAILURE
  PSA_ERROR_HARDWARE_FAILURE
  PSA_ERROR_CORRUPTION_DETECTED
  PSA_ERROR_STORAGE_FAILURE
  PSA_ERROR_INSUFFICIENT_ENTROPY
  PSA_ERROR_INVALID_PADDING
  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.