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## org.bouncycastle.crypto.signers
Class HMacDSAKCalculator

    java.lang.Object
      org.bouncycastle.crypto.signers.HMacDSAKCalculator

All Implemented Interfaces:
  DSAKCalculator

public class HMacDSAKCalculator
extends java.lang.Object
implements DSAKCalculator

A deterministic K calculator based on the algorithm in section 3.2 of RFC 6979.

Constructor Summary
`HMacDSAKCalculator(Digest digest)` Base constructor.

Method Summary
`void` | `init(java.math.BigInteger n, java.math.BigInteger d, byte[] message)` Deterministic initialiser.
`void` | `init(java.math.BigInteger n, java.security.SecureRandom random)` Non-deterministic initialiser.
`protected void` | `initAdditionalInput0(HMac hmac0)` Supply additional input to HMAC_K(V || 0x00 || int2octets(x) || bits2octets(h1)).
`protected void` | `initAdditionalInput1(HMac hmac1)` Supply additional input to HMAC_K(V || 0x01 || int2octets(x) || bits2octets(h1)).
`boolean` | `isDeterministic()` Return true if this calculator is deterministic, false otherwise.
`java.math.BigInteger` | `nextK()` Return the next valid value of K.

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Constructor Detail

### HMacDSAKCalculator

    public HMacDSAKCalculator(Digest digest)

  Base constructor.

Parameters:
  `digest` - digest to build the HMAC on.

Method Detail

### isDeterministic

    public boolean isDeterministic()

  Description copied from interface: `DSAKCalculator`
  Return true if this calculator is deterministic, false otherwise.

  Specified by:
    `isDeterministic` in interface `DSAKCalculator`
  Returns:
    true if deterministic, otherwise false.

### init

    public void init(java.math.BigInteger n,
                     java.security.SecureRandom random)

  Description copied from interface: `DSAKCalculator`
  Non-deterministic initialiser.

  Specified by:
    `init` in interface `DSAKCalculator`
  Parameters:
    `n` - the order of the DSA group.
    `random` - a source of randomness.

### init

    public void init(java.math.BigInteger n,
                     java.math.BigInteger d,
                     byte[] message)

  Description copied from interface: `DSAKCalculator`
  Deterministic initialiser.

  Specified by:
    `init` in interface `DSAKCalculator`
  Parameters:
    `n` - the order of the DSA group.
    `d` - the DSA private value.
    `message` - the message being signed.

### nextK

    public java.math.BigInteger nextK()

  Description copied from interface: `DSAKCalculator`
  Return the next valid value of K.

  Specified by:
    `nextK` in interface `DSAKCalculator`
  Returns:
    a K value.

### initAdditionalInput0

    protected void initAdditionalInput0(HMac hmac0)

  Supply additional input to HMAC_K(V || 0x00 || int2octets(x) || bits2octets(h1)).

  RFC 6979 3.6. Additional data may be added to the input of HMAC [..]. A use case may be a protocol that requires a non-deterministic signature algorithm on a system that does not have access to a high-quality random source. It suffices that the additional data [..] is non-repeating (e.g., a signature counter or a monotonic clock) to ensure "random-looking" signatures are indistinguishable, in a cryptographic way, from plain (EC)DSA signatures.

  By default there is no additional input. Override this method to supply additional input, bearing in mind that this calculator may be used for many signatures.

  Parameters:
    `hmac0` - the `HMac` to which the additional input should be added.

### initAdditionalInput1

    protected void initAdditionalInput1(HMac hmac1)

  Supply additional input to HMAC_K(V || 0x01 || int2octets(x) || bits2octets(h1)).

  Refer to comments for `initAdditionalInput0(HMac)`.

  Parameters:
    `hmac1` - the `HMac` to which the additional input should be added.

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