HMac (Bouncy Castle Library 1.54 API Specification)
Date: 2015-12-29

org.bouncycastle.crypto.macs

## Class HMac

- java.lang.Object
- - org.bouncycastle.crypto.macs.HMac

- All Implemented Interfaces:
    Mac

      public class HMac
      extends java.lang.Object
      implements Mac

  HMAC implementation based on RFC2104 H(K XOR opad, H(K XOR ipad, text))

- - ### Constructor Summary

    Constructors
    Constructor and Description
    `HMac(Digest digest)` Base constructor for one of the standard digest algorithms that the byteLength of the algorithm is know for.

  - ### Method Summary

    Methods
    Modifier and Type | Method and Description
    --- | ---
    `int` | `doFinal(byte[] out, int outOff)` Compute the final stage of the MAC writing the output to the out parameter.
    `java.lang.String` | `getAlgorithmName()` Return the name of the algorithm the MAC implements.
    `int` | `getMacSize()` Return the block size for this MAC (in bytes).
    `Digest` | `getUnderlyingDigest()`
    `void` | `init(CipherParameters params)` Initialise the MAC.
    `void` | `reset()` Reset the mac generator.
    `void` | `update(byte in)` add a single byte to the mac for processing.
    `void` | `update(byte[] in, int inOff, int len)`

    - ### Methods inherited from class java.lang.Object

      `clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

- - ### Constructor Detail

    - #### HMac

          public HMac(Digest digest)

      Base constructor for one of the standard digest algorithms that the byteLength of the algorithm is know for.
      Parameters:
        `digest` - the digest.

  - ### Method Detail

    - #### getAlgorithmName

          public java.lang.String getAlgorithmName()

      Description copied from interface: `Mac`
      Return the name of the algorithm the MAC implements.
      Specified by:
        `getAlgorithmName` in interface `Mac`
      Returns:
        the name of the algorithm the MAC implements.

    - #### getUnderlyingDigest

          public Digest getUnderlyingDigest()

    - #### init

          public void init(CipherParameters params)

      Description copied from interface: `Mac`
      Initialise the MAC.
      Specified by:
        `init` in interface `Mac`
      Parameters:
        `params` - the key and other data required by the MAC.

    - #### getMacSize

          public int getMacSize()

      Description copied from interface: `Mac`
      Return the block size for this MAC (in bytes).
      Specified by:
        `getMacSize` in interface `Mac`
      Returns:
        the block size for this MAC in bytes.

    - #### update

          public void update(byte in)

      Description copied from interface: `Mac`
      add a single byte to the mac for processing.
      Specified by:
        `update` in interface `Mac`
      Parameters:
        `in` - the byte to be processed.

    - #### update

          public void update(byte[] in,
                    int inOff,
                    int len)

      Specified by:
        `update` in interface `Mac`
      Parameters:
        `in` - the array containing the input.
        `inOff` - the index in the array the data begins at.
        `len` - the length of the input starting at inOff.

    - #### doFinal

          public int doFinal(byte[] out,
                    int outOff)

      Description copied from interface: `Mac`
      Compute the final stage of the MAC writing the output to the out parameter.

      doFinal leaves the MAC in the same state it was after the last init.

      Specified by:
        `doFinal` in interface `Mac`
      Parameters:
        `out` - the array the MAC is to be output to.
        `outOff` - the offset into the out buffer the output is to start at.

    - #### reset

          public void reset()

      Reset the mac generator.
      Specified by:
        `reset` in interface `Mac`