Next: The MacFactory Class, Previous: Message Authentication Codes, Up: Message Authentication Codes
A key in the attributes map passed to the
init
method. The value is taken to be a byte array, which contains the key as raw bytes. The length of the key must be at least the length of the computed hash in the case of hash-based MACs.
The actual size of the returned hash, taken from the first bytes of the raw result. The value must be a
java.lang.Integer
containing the desired length, which should not be smaller than 80 bits or one half the MAC's usual output length, whichever is larger.
Initializes this MAC instance with a specified attributes map, which maps keys (such as
MAC_KEY_MATERIAL
) to parameters (such as the key bytes). Throws ajava.security.InvalidKeyException
if the key is unacceptable or omitted, and trows ajava.lang.IllegalStateException
if this instance has already been initialized.
Continues the computation of the MAC with a portion of the byte array in, starting at offset and considering length bytes.
Finishes the computation of the MAC and returns it in a new byte array. The instance is reset after this method returns.
Resets the internal state of this instance, which may then be re-initialized.