Package org.bouncycastle.crypto.signers

Class HMacDSAKCalculator

java.lang.Object
org.bouncycastle.crypto.signers.HMacDSAKCalculator
All Implemented Interfaces:
DSAKCalculator
public class HMacDSAKCalculator extends Object implements DSAKCalculator
A deterministic K calculator based on the algorithm in section 3.2 of RFC 6979.

  • Constructor Details

    • HMacDSAKCalculator

      public HMacDSAKCalculator(Digest digest)
      Base constructor.
      Parameters:
      digest - digest to build the HMAC on.

  • Method Details

    • 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(BigInteger n, 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(BigInteger n, 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 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.