Message Authentication Codes

A message authentication code (MAC) is a short piece of information used to authenticate a message — in other words, to confirm that the message came from the stated sender (its authenticity) and has not been changed in transit (its integrity).

wolfcrypt implements the Hash-based message authentication code (HMAC), which uses a cryptographic hash function coupled with a secret key to produce message authentication codes.

Hmac Classes

Interface

All Hmac classes available in this module implements the following interface:

SHA-1

Attention

NIST has deprecated SHA-1 in favor of the SHA-2 variants. New applications are strongly suggested to use SHA-2 over SHA-1.

SHA-2 family

Example

>>> from wolfcrypt.hashes import HmacSha256
>>>
>>> h = HmacSha256('secret')
>>> h.update("wolf")
>>> h.update("crypt")
>>> h.digest()
b'\x18\xbf*\t9\xa2o\xdf\\\xc8\xe0\xc2U\x94,\x8dY\x02;\x1c<Q\xdf\x8d\xdb\x863\xfb\xc1f#o'
>>> h.hexdigest()
b'18bf2a0939a26fdf5cc8e0c255942c8d59023b1c3c51df8ddb8633fbc166236f'
>>>
>>> h.update("rocks")
>>> h.hexdigest()
b'85dc8c1995d20b17942d52773d8a597d028ad958e5736beafb59a4742f63889e'
>>>
>>> HmacSha256('secret', 'wolfcryptrocks').hexdigest()
b'85dc8c1995d20b17942d52773d8a597d028ad958e5736beafb59a4742f63889e'
>>>
>>> HmacSha256.new('secret', 'wolfcryptrocks').hexdigest()
b'85dc8c1995d20b17942d52773d8a597d028ad958e5736beafb59a4742f63889e'