The following functions are to be used for low-level cryptographic operations. Their prototypes lie in gnutls/crypto.h.
Note that due to historic reasons several functions, (e.g. gnutls_mac_list, gnutls_mac_get_name) of this API are part of the Core TLS API.
int gnutls_aead_cipher_decrypt (gnutls_aead_cipher_hd_t handle, const void * nonce, size_t nonce_len, const void * auth, size_t auth_len, size_t tag_size, const void * ctext, size_t ctext_len, void * ptext, size_t * ptext_len) ¶handle: is a gnutls_aead_cipher_hd_t type.
nonce: the nonce to set
nonce_len: The length of the nonce
auth: additional data to be authenticated
auth_len: The length of the data
tag_size: The size of the tag to use (use zero for the default)
ctext: the data to decrypt (including the authentication tag)
ctext_len: the length of data to decrypt (includes tag size)
ptext: the decrypted data
ptext_len: the length of decrypted data (initially must hold the maximum available size)
This function will decrypt the given data using the algorithm specified by the context. This function must be provided the complete data to be decrypted, including the authentication tag. On several AEAD ciphers, the authentication tag is appended to the ciphertext, though this is not a general rule. This function will fail if the tag verification fails.
Returns: Zero or a negative error code on verification failure or other error.
Since: 3.4.0
int gnutls_aead_cipher_decryptv2 (gnutls_aead_cipher_hd_t handle, const void * nonce, size_t nonce_len, const giovec_t * auth_iov, int auth_iovcnt, const giovec_t * iov, int iovcnt, void * tag, size_t tag_size) ¶handle: is a gnutls_aead_cipher_hd_t type.
nonce: the nonce to set
nonce_len: The length of the nonce
auth_iov: additional data to be authenticated
auth_iovcnt: The number of buffers in auth_iov
iov: the data to decrypt
iovcnt: The number of buffers in iov
tag: The authentication tag
tag_size: The size of the tag to use (use zero for the default)
This is similar to gnutls_aead_cipher_decrypt() , but it performs
in-place encryption on the provided data buffers.
Returns: Zero or a negative error code on error.
Since: 3.6.10
void gnutls_aead_cipher_deinit (gnutls_aead_cipher_hd_t handle) ¶handle: is a gnutls_aead_cipher_hd_t type.
This function will deinitialize all resources occupied by the given authenticated-encryption context.
Since: 3.4.0
int gnutls_aead_cipher_encrypt (gnutls_aead_cipher_hd_t handle, const void * nonce, size_t nonce_len, const void * auth, size_t auth_len, size_t tag_size, const void * ptext, size_t ptext_len, void * ctext, size_t * ctext_len) ¶handle: is a gnutls_aead_cipher_hd_t type.
nonce: the nonce to set
nonce_len: The length of the nonce
auth: additional data to be authenticated
auth_len: The length of the data
tag_size: The size of the tag to use (use zero for the default)
ptext: the data to encrypt
ptext_len: The length of data to encrypt
ctext: the encrypted data including authentication tag
ctext_len: the length of encrypted data (initially must hold the maximum available size, including space for tag)
This function will encrypt the given data using the algorithm specified by the context. The output data will contain the authentication tag.
Returns: Zero or a negative error code on error.
Since: 3.4.0
int gnutls_aead_cipher_encryptv (gnutls_aead_cipher_hd_t handle, const void * nonce, size_t nonce_len, const giovec_t * auth_iov, int auth_iovcnt, size_t tag_size, const giovec_t * iov, int iovcnt, void * ctext, size_t * ctext_len) ¶handle: is a gnutls_aead_cipher_hd_t type.
nonce: the nonce to set
nonce_len: The length of the nonce
auth_iov: additional data to be authenticated
auth_iovcnt: The number of buffers in auth_iov
tag_size: The size of the tag to use (use zero for the default)
iov: the data to be encrypted
iovcnt: The number of buffers in iov
ctext: the encrypted data including authentication tag
ctext_len: the length of encrypted data (initially must hold the maximum available size, including space for tag)
This function will encrypt the provided data buffers using the algorithm specified by the context. The output data will contain the authentication tag.
Returns: Zero or a negative error code on error.
Since: 3.6.3
int gnutls_aead_cipher_encryptv2 (gnutls_aead_cipher_hd_t handle, const void * nonce, size_t nonce_len, const giovec_t * auth_iov, int auth_iovcnt, const giovec_t * iov, int iovcnt, void * tag, size_t * tag_size) ¶handle: is a gnutls_aead_cipher_hd_t type.
nonce: the nonce to set
nonce_len: The length of the nonce
auth_iov: additional data to be authenticated
auth_iovcnt: The number of buffers in auth_iov
iov: the data to be encrypted
iovcnt: The number of buffers in iov
tag: The authentication tag
tag_size: The size of the tag to use (use zero for the default)
This is similar to gnutls_aead_cipher_encrypt() , but it performs
in-place encryption on the provided data buffers.
Returns: Zero or a negative error code on error.
Since: 3.6.10
int gnutls_aead_cipher_init (gnutls_aead_cipher_hd_t * handle, gnutls_cipher_algorithm_t cipher, const gnutls_datum_t * key) ¶handle: is a gnutls_aead_cipher_hd_t type.
cipher: the authenticated-encryption algorithm to use
key: The key to be used for encryption
This function will initialize an context that can be used for encryption/decryption of data. This will effectively use the current crypto backend in use by gnutls or the cryptographic accelerator in use.
Returns: Zero or a negative error code on error.
Since: 3.4.0
int gnutls_aead_cipher_set_key (gnutls_aead_cipher_hd_t handle, const gnutls_datum_t * key) ¶handle: is a gnutls_aead_cipher_hd_t type.
key: The key to be used for encryption
This function will set a new key without re-initializing the context.
Returns: Zero or a negative error code on error.
Since: 3.7.5
int gnutls_cipher_add_auth (gnutls_cipher_hd_t handle, const void * ptext, size_t ptext_size) ¶handle: is a gnutls_cipher_hd_t type
ptext: the data to be authenticated
ptext_size: the length of the data
This function operates on authenticated encryption with associated data (AEAD) ciphers and authenticate the input data. This function can only be called once and before any encryption operations.
Returns: Zero or a negative error code on error.
Since: 3.0
int gnutls_cipher_decrypt (gnutls_cipher_hd_t handle, void * ctext, size_t ctext_len) ¶handle: is a gnutls_cipher_hd_t type
ctext: the data to decrypt
ctext_len: the length of data to decrypt
This function will decrypt the given data using the algorithm specified by the context.
Note that in AEAD ciphers, this will not check the tag. You will
need to compare the tag sent with the value returned from gnutls_cipher_tag() .
Returns: Zero or a negative error code on error.
Since: 2.10.0
int gnutls_cipher_decrypt2 (gnutls_cipher_hd_t handle, const void * ctext, size_t ctext_len, void * ptext, size_t ptext_len) ¶handle: is a gnutls_cipher_hd_t type
ctext: the data to decrypt
ctext_len: the length of data to decrypt
ptext: the decrypted data
ptext_len: the available length for decrypted data
This function will decrypt the given data using the algorithm
specified by the context. For block ciphers the ctext_len must be
a multiple of the block size. For the supported ciphers the plaintext
data length will equal the ciphertext size.
Note that in AEAD ciphers, this will not check the tag. You will
need to compare the tag sent with the value returned from gnutls_cipher_tag() .
Returns: Zero or a negative error code on error.
Since: 2.12.0
int gnutls_cipher_decrypt3 (gnutls_cipher_hd_t handle, const void * ctext, size_t ctext_len, void * ptext, size_t * ptext_len, unsigned flags) ¶handle: is a gnutls_cipher_hd_t type
ctext: the data to decrypt
ctext_len: the length of data to decrypt
ptext: the decrypted data
ptext_len: the available length for decrypted data
flags: flags for padding
This function will decrypt the given data using the algorithm
specified by the context. If flags is specified, padding for the
decrypted data will be removed accordingly and ptext_len will be
updated.
Returns: Zero or a negative error code on error.
Since: 3.7.7
void gnutls_cipher_deinit (gnutls_cipher_hd_t handle) ¶handle: is a gnutls_cipher_hd_t type
This function will deinitialize all resources occupied by the given encryption context.
Since: 2.10.0
int gnutls_cipher_encrypt (gnutls_cipher_hd_t handle, void * ptext, size_t ptext_len) ¶handle: is a gnutls_cipher_hd_t type
ptext: the data to encrypt
ptext_len: the length of data to encrypt
This function will encrypt the given data using the algorithm specified by the context.
Returns: Zero or a negative error code on error.
Since: 2.10.0
int gnutls_cipher_encrypt2 (gnutls_cipher_hd_t handle, const void * ptext, size_t ptext_len, void * ctext, size_t ctext_len) ¶handle: is a gnutls_cipher_hd_t type
ptext: the data to encrypt
ptext_len: the length of data to encrypt
ctext: the encrypted data
ctext_len: the available length for encrypted data
This function will encrypt the given data using the algorithm
specified by the context. For block ciphers the ptext_len must be
a multiple of the block size. For the supported ciphers the encrypted
data length will equal the plaintext size.
Returns: Zero or a negative error code on error.
Since: 2.12.0
int gnutls_cipher_encrypt3 (gnutls_cipher_hd_t handle, const void * ptext, size_t ptext_len, void * ctext, size_t * ctext_len, unsigned flags) ¶handle: is a gnutls_cipher_hd_t type
ptext: the data to encrypt
ptext_len: the length of data to encrypt
ctext: the encrypted data
ctext_len: the length of encrypted data (initially must hold the maximum available size)
flags: flags for padding
This function will encrypt the given data using the algorithm
specified by the context. For block ciphers, ptext_len is
typically a multiple of the block size. If not, the caller can
instruct the function to pad the last block according to flags .
Currently, the only available padding scheme is
GNUTLS_CIPHER_PADDING_PKCS7 .
If ctext is not NULL , it must hold enough space to store
resulting cipher text. To check the required size, this function
can be called with ctext set to NULL . Then ctext_len will be
updated without performing actual encryption.
Returns: Zero or a negative error code on error.
Since: 3.7.7
unsigned gnutls_cipher_get_block_size (gnutls_cipher_algorithm_t algorithm) ¶algorithm: is an encryption algorithm
Returns: the block size of the encryption algorithm.
Since: 2.10.0
unsigned gnutls_cipher_get_iv_size (gnutls_cipher_algorithm_t algorithm) ¶algorithm: is an encryption algorithm
This function returns the size of the initialization vector (IV) for the provided algorithm. For algorithms with variable size IV (e.g., AES-CCM), the returned size will be the one used by TLS.
Returns: block size for encryption algorithm.
Since: 3.2.0
unsigned gnutls_cipher_get_tag_size (gnutls_cipher_algorithm_t algorithm) ¶algorithm: is an encryption algorithm
This function returns the tag size of an authenticated encryption algorithm. For non-AEAD algorithms, it returns zero.
Returns: the tag size of the authenticated encryption algorithm.
Since: 3.2.2
int gnutls_cipher_init (gnutls_cipher_hd_t * handle, gnutls_cipher_algorithm_t cipher, const gnutls_datum_t * key, const gnutls_datum_t * iv) ¶handle: is a gnutls_cipher_hd_t type
cipher: the encryption algorithm to use
key: the key to be used for encryption/decryption
iv: the IV to use (if not applicable set NULL)
This function will initialize the handle context to be usable
for encryption/decryption of data. This will effectively use the
current crypto backend in use by gnutls or the cryptographic
accelerator in use.
Returns: Zero or a negative error code on error.
Since: 2.10.0
void gnutls_cipher_set_iv (gnutls_cipher_hd_t handle, void * iv, size_t ivlen) ¶handle: is a gnutls_cipher_hd_t type
iv: the IV to set
ivlen: the length of the IV
This function will set the IV to be used for the next encryption block.
Since: 3.0
int gnutls_cipher_tag (gnutls_cipher_hd_t handle, void * tag, size_t tag_size) ¶handle: is a gnutls_cipher_hd_t type
tag: will hold the tag
tag_size: the length of the tag to return
This function operates on authenticated encryption with associated data (AEAD) ciphers and will return the output tag.
Returns: Zero or a negative error code on error.
Since: 3.0
int gnutls_crypto_register_aead_cipher (gnutls_cipher_algorithm_t algorithm, int priority, gnutls_cipher_init_func init, gnutls_cipher_setkey_func setkey, gnutls_cipher_aead_encrypt_func aead_encrypt, gnutls_cipher_aead_decrypt_func aead_decrypt, gnutls_cipher_deinit_func deinit) ¶algorithm: is the gnutls AEAD cipher identifier
priority: is the priority of the algorithm
init: A function which initializes the cipher
setkey: A function which sets the key of the cipher
aead_encrypt: Perform the AEAD encryption
aead_decrypt: Perform the AEAD decryption
deinit: A function which deinitializes the cipher
This function will register a cipher algorithm to be used by gnutls. Any algorithm registered will override the included algorithms and by convention kernel implemented algorithms have priority of 90 and CPU-assisted of 80. The algorithm with the lowest priority will be used by gnutls.
In the case the registered init or setkey functions return GNUTLS_E_NEED_FALLBACK ,
GnuTLS will attempt to use the next in priority registered cipher.
The functions registered will be used with the new AEAD API introduced in GnuTLS 3.4.0. Internally GnuTLS uses the new AEAD API.
Deprecated: since 3.7.0 it is no longer possible to override cipher implementation
Returns: GNUTLS_E_SUCCESS on success, otherwise a negative error code.
Since: 3.4.0
int gnutls_crypto_register_cipher (gnutls_cipher_algorithm_t algorithm, int priority, gnutls_cipher_init_func init, gnutls_cipher_setkey_func setkey, gnutls_cipher_setiv_func setiv, gnutls_cipher_encrypt_func encrypt, gnutls_cipher_decrypt_func decrypt, gnutls_cipher_deinit_func deinit) ¶algorithm: is the gnutls algorithm identifier
priority: is the priority of the algorithm
init: A function which initializes the cipher
setkey: A function which sets the key of the cipher
setiv: A function which sets the nonce/IV of the cipher (non-AEAD)
encrypt: A function which performs encryption (non-AEAD)
decrypt: A function which performs decryption (non-AEAD)
deinit: A function which deinitializes the cipher
This function will register a cipher algorithm to be used by gnutls. Any algorithm registered will override the included algorithms and by convention kernel implemented algorithms have priority of 90 and CPU-assisted of 80. The algorithm with the lowest priority will be used by gnutls.
In the case the registered init or setkey functions return GNUTLS_E_NEED_FALLBACK ,
GnuTLS will attempt to use the next in priority registered cipher.
The functions which are marked as non-AEAD they are not required when registering a cipher to be used with the new AEAD API introduced in GnuTLS 3.4.0. Internally GnuTLS uses the new AEAD API.
Deprecated: since 3.7.0 it is no longer possible to override cipher implementation
Returns: GNUTLS_E_SUCCESS on success, otherwise a negative error code.
Since: 3.4.0
int gnutls_crypto_register_digest (gnutls_digest_algorithm_t algorithm, int priority, gnutls_digest_init_func init, gnutls_digest_hash_func hash, gnutls_digest_output_func output, gnutls_digest_deinit_func deinit, gnutls_digest_fast_func hash_fast) ¶algorithm: is the gnutls digest identifier
priority: is the priority of the algorithm
init: A function which initializes the digest
hash: Perform the hash operation
output: Provide the output of the digest
deinit: A function which deinitializes the digest
hash_fast: Perform the digest operation in one go
This function will register a digest algorithm to be used by gnutls. Any algorithm registered will override the included algorithms and by convention kernel implemented algorithms have priority of 90 and CPU-assisted of 80. The algorithm with the lowest priority will be used by gnutls.
Deprecated: since 3.7.0 it is no longer possible to override cipher implementation
Returns: GNUTLS_E_SUCCESS on success, otherwise a negative error code.
Since: 3.4.0
int gnutls_crypto_register_mac (gnutls_mac_algorithm_t algorithm, int priority, gnutls_mac_init_func init, gnutls_mac_setkey_func setkey, gnutls_mac_setnonce_func setnonce, gnutls_mac_hash_func hash, gnutls_mac_output_func output, gnutls_mac_deinit_func deinit, gnutls_mac_fast_func hash_fast) ¶algorithm: is the gnutls MAC identifier
priority: is the priority of the algorithm
init: A function which initializes the MAC
setkey: A function which sets the key of the MAC
setnonce: A function which sets the nonce for the mac (may be NULL for common MAC algorithms)
hash: Perform the hash operation
output: Provide the output of the MAC
deinit: A function which deinitializes the MAC
hash_fast: Perform the MAC operation in one go
This function will register a MAC algorithm to be used by gnutls. Any algorithm registered will override the included algorithms and by convention kernel implemented algorithms have priority of 90 and CPU-assisted of 80. The algorithm with the lowest priority will be used by gnutls.
Deprecated: since 3.7.0 it is no longer possible to override cipher implementation
Returns: GNUTLS_E_SUCCESS on success, otherwise a negative error code.
Since: 3.4.0
int gnutls_decode_ber_digest_info (const gnutls_datum_t * info, gnutls_digest_algorithm_t * hash, unsigned char * digest, unsigned int * digest_size) ¶info: an RSA BER encoded DigestInfo structure
hash: will contain the hash algorithm of the structure
digest: will contain the hash output of the structure
digest_size: will contain the hash size of the structure; initially must hold the maximum size of digest
This function will parse an RSA PKCS1 1.5 DigestInfo structure
and report the hash algorithm used as well as the digest data.
Returns: On success, GNUTLS_E_SUCCESS (0) is returned, otherwise
an error code is returned.
Since: 3.5.0
int gnutls_decode_gost_rs_value (const gnutls_datum_t * sig_value, gnutls_datum_t * r, gnutls_datum_t * s) ¶sig_value: will holds a GOST signature according to RFC 4491 section 2.2.2
r: will contain the r value
s: will contain the s value
This function will decode the provided sig_value , into r and s elements.
See RFC 4491 section 2.2.2 for the format of signature value.
The output values may be padded with a zero byte to prevent them
from being interpreted as negative values. The value
should be deallocated using gnutls_free() .
Returns: On success, GNUTLS_E_SUCCESS (0) is returned, otherwise
an error code is returned.
Since: 3.6.0
int gnutls_decode_rs_value (const gnutls_datum_t * sig_value, gnutls_datum_t * r, gnutls_datum_t * s) ¶sig_value: holds a Dss-Sig-Value DER or BER encoded structure
r: will contain the r value
s: will contain the s value
This function will decode the provided sig_value ,
into r and s elements. The Dss-Sig-Value is used for DSA and ECDSA
signatures.
The output values may be padded with a zero byte to prevent them
from being interpreted as negative values. The value
should be deallocated using gnutls_free() .
Returns: On success, GNUTLS_E_SUCCESS (0) is returned, otherwise
an error code is returned.
Since: 3.6.0
int gnutls_encode_ber_digest_info (gnutls_digest_algorithm_t hash, const gnutls_datum_t * digest, gnutls_datum_t * output) ¶hash: the hash algorithm that was used to get the digest
digest: must contain the digest data
output: will contain the allocated DigestInfo BER encoded data
This function will encode the provided digest data, and its
algorithm into an RSA PKCS1 1.5 DigestInfo structure.
Returns: On success, GNUTLS_E_SUCCESS (0) is returned, otherwise
an error code is returned.
Since: 3.5.0
int gnutls_encode_gost_rs_value (gnutls_datum_t * sig_value, const gnutls_datum_t * r, const gnutls_datum_t * s) ¶sig_value: will hold a GOST signature according to RFC 4491 section 2.2.2
r: must contain the r value
s: must contain the s value
This function will encode the provided r and s values, into binary representation according to RFC 4491 section 2.2.2, used for GOST R 34.10-2001 (and thus also for GOST R 34.10-2012) signatures.
The output value should be deallocated using gnutls_free() .
Returns: On success, GNUTLS_E_SUCCESS (0) is returned, otherwise
an error code is returned.
Since: 3.6.0
int gnutls_encode_rs_value (gnutls_datum_t * sig_value, const gnutls_datum_t * r, const gnutls_datum_t * s) ¶sig_value: will hold a Dss-Sig-Value DER encoded structure
r: must contain the r value
s: must contain the s value
This function will encode the provided r and s values, into a Dss-Sig-Value structure, used for DSA and ECDSA signatures.
The output value should be deallocated using gnutls_free() .
Returns: On success, GNUTLS_E_SUCCESS (0) is returned, otherwise
an error code is returned.
Since: 3.6.0
int gnutls_hash (gnutls_hash_hd_t handle, const void * ptext, size_t ptext_len) ¶handle: is a gnutls_hash_hd_t type
ptext: the data to hash
ptext_len: the length of data to hash
This function will hash the given data using the algorithm specified by the context.
Returns: Zero or a negative error code on error.
Since: 2.10.0
gnutls_hash_hd_t gnutls_hash_copy (gnutls_hash_hd_t handle) ¶handle: is a gnutls_hash_hd_t type
This function will create a copy of Message Digest context, containing all
its current state. Copying contexts for Message Digests registered using
gnutls_crypto_register_digest() is not supported and will always result in
an error. In addition to that, some of the Message Digest implementations do
not support this operation. Applications should check the return value and
provide a proper fallback.
Returns: new Message Digest context or NULL in case of an error.
Since: 3.6.9
void gnutls_hash_deinit (gnutls_hash_hd_t handle, void * digest) ¶handle: is a gnutls_hash_hd_t type
digest: is the output value of the hash
This function will deinitialize all resources occupied by the given hash context.
Since: 2.10.0
int gnutls_hash_fast (gnutls_digest_algorithm_t algorithm, const void * ptext, size_t ptext_len, void * digest) ¶algorithm: the hash algorithm to use
ptext: the data to hash
ptext_len: the length of data to hash
digest: is the output value of the hash
This convenience function will hash the given data and return output on a single call.
Returns: Zero or a negative error code on error.
Since: 2.10.0
unsigned gnutls_hash_get_len (gnutls_digest_algorithm_t algorithm) ¶algorithm: the hash algorithm to use
This function will return the length of the output data of the given hash algorithm.
Returns: The length or zero on error.
Since: 2.10.0
int gnutls_hash_init (gnutls_hash_hd_t * dig, gnutls_digest_algorithm_t algorithm) ¶dig: is a gnutls_hash_hd_t type
algorithm: the hash algorithm to use
This function will initialize an context that can be used to produce a Message Digest of data. This will effectively use the current crypto backend in use by gnutls or the cryptographic accelerator in use.
Returns: Zero or a negative error code on error.
Since: 2.10.0
void gnutls_hash_output (gnutls_hash_hd_t handle, void * digest) ¶handle: is a gnutls_hash_hd_t type
digest: is the output value of the hash
This function will output the current hash value and reset the
state of the hash. If digest is NULL , it only resets the state of
the hash.
Since: 2.10.0
int gnutls_hash_squeeze (gnutls_hash_hd_t handle, void * output, size_t length) ¶handle: a gnutls_hash_hd_t
output: destination to store the output; must be equal to or larger than length
length: length of output
This function will extract digest output of length bytes. The handle must
be initialized with gnutls_hash_init() as an extended output function (XOF),
such as GNUTLS_DIG_SHAKE_128 or GNUTLS_DIG_SHAKE_256 .
This function can be called multiple times. To reset the state of handle ,
call gnutls_hash_deinit() with NULL as the digest argument.
Returns: GNUTLS_E_SUCCESS (0) on success; negative error code otherwise.
Since: 3.8.6
int gnutls_hkdf_expand (gnutls_mac_algorithm_t mac, const gnutls_datum_t * key, const gnutls_datum_t * info, void * output, size_t length) ¶mac: the mac algorithm used internally
key: the pseudorandom key created with HKDF-Extract
info: the optional informational data
output: the output value of the expand operation
length: the desired length of the output key
This function will derive a variable length keying material from the pseudorandom key using the HKDF-Expand function as defined in RFC 5869.
Returns: Zero or a negative error code on error.
Since: 3.6.13
int gnutls_hkdf_extract (gnutls_mac_algorithm_t mac, const gnutls_datum_t * key, const gnutls_datum_t * salt, void * output) ¶mac: the mac algorithm used internally
key: the initial keying material
salt: the optional salt
output: the output value of the extract operation
This function will derive a fixed-size key using the HKDF-Extract function as defined in RFC 5869.
Returns: Zero or a negative error code on error.
Since: 3.6.13
int gnutls_hmac (gnutls_hmac_hd_t handle, const void * ptext, size_t ptext_len) ¶handle: is a gnutls_hmac_hd_t type
ptext: the data to hash
ptext_len: the length of data to hash
This function will hash the given data using the algorithm specified by the context.
Returns: Zero or a negative error code on error.
Since: 2.10.0
gnutls_hmac_hd_t gnutls_hmac_copy (gnutls_hmac_hd_t handle) ¶handle: is a gnutls_hmac_hd_t type
This function will create a copy of MAC context, containing all its current
state. Copying contexts for MACs registered using
gnutls_crypto_register_mac() is not supported and will always result in an
error. In addition to that, some of the MAC implementations do not support
this operation. Applications should check the return value and provide a
proper fallback.
Returns: new MAC context or NULL in case of an error.
Since: 3.6.9
void gnutls_hmac_deinit (gnutls_hmac_hd_t handle, void * digest) ¶handle: is a gnutls_hmac_hd_t type
digest: is the output value of the MAC
This function will deinitialize all resources occupied by the given hmac context.
Since: 2.10.0
int gnutls_hmac_fast (gnutls_mac_algorithm_t algorithm, const void * key, size_t keylen, const void * ptext, size_t ptext_len, void * digest) ¶algorithm: the hash algorithm to use
key: the key to use
keylen: the length of the key
ptext: the data to hash
ptext_len: the length of data to hash
digest: is the output value of the hash
This convenience function will hash the given data and return output on a single call. Note, this call will not work for MAC algorithms that require nonce (like UMAC or GMAC).
Returns: Zero or a negative error code on error.
Since: 2.10.0
unsigned gnutls_hmac_get_key_size (gnutls_mac_algorithm_t algorithm) ¶algorithm: the mac algorithm to use
This function will return the size of the key to be used with this algorithm. On the algorithms which may accept arbitrary key sizes, the returned size is the MAC key size used in the TLS protocol.
Returns: The key size or zero on error.
Since: 3.6.12
unsigned gnutls_hmac_get_len (gnutls_mac_algorithm_t algorithm) ¶algorithm: the hmac algorithm to use
This function will return the length of the output data of the given hmac algorithm.
Returns: The length or zero on error.
Since: 2.10.0
int gnutls_hmac_init (gnutls_hmac_hd_t * dig, gnutls_mac_algorithm_t algorithm, const void * key, size_t keylen) ¶dig: is a gnutls_hmac_hd_t type
algorithm: the HMAC algorithm to use
key: the key to be used for encryption
keylen: the length of the key
This function will initialize an context that can be used to produce a Message Authentication Code (MAC) of data. This will effectively use the current crypto backend in use by gnutls or the cryptographic accelerator in use.
Note that despite the name of this function, it can be used for other MAC algorithms than HMAC.
Returns: Zero or a negative error code on error.
Since: 2.10.0
void gnutls_hmac_output (gnutls_hmac_hd_t handle, void * digest) ¶handle: is a gnutls_hmac_hd_t type
digest: is the output value of the MAC
This function will output the current MAC value and reset the state of the MAC.
Since: 2.10.0
void gnutls_hmac_set_nonce (gnutls_hmac_hd_t handle, const void * nonce, size_t nonce_len) ¶handle: is a gnutls_hmac_hd_t type
nonce: the data to set as nonce
nonce_len: the length of data
This function will set the nonce in the MAC algorithm.
Since: 3.2.0
size_t gnutls_mac_get_nonce_size (gnutls_mac_algorithm_t algorithm) ¶algorithm: is an encryption algorithm
Returns the size of the nonce used by the MAC in TLS.
Returns: length (in bytes) of the given MAC nonce size, or 0.
Since: 3.2.0
int gnutls_pbkdf2 (gnutls_mac_algorithm_t mac, const gnutls_datum_t * key, const gnutls_datum_t * salt, unsigned iter_count, void * output, size_t length) ¶mac: the mac algorithm used internally
key: the initial keying material
salt: the salt
iter_count: the iteration count
output: the output value
length: the desired length of the output key
This function will derive a variable length keying material from
a password according to PKCS 5 PBKDF2.
Returns: Zero or a negative error code on error.
Since: 3.6.13
int gnutls_rnd (gnutls_rnd_level_t level, void * data, size_t len) ¶level: a security level
data: place to store random bytes
len: The requested size
This function will generate random data and store it to output
buffer. The value of level should be one of GNUTLS_RND_NONCE ,
GNUTLS_RND_RANDOM and GNUTLS_RND_KEY . See the manual and
gnutls_rnd_level_t for detailed information.
This function is thread-safe and also fork-safe.
Returns: Zero on success, or a negative error code on error.
Since: 2.12.0
void gnutls_rnd_refresh ( void) ¶This function refreshes the random generator state. That is the current precise time, CPU usage, and other values are input into its state.
On a slower rate input from /dev/urandom is mixed too.
Since: 3.1.7