http://www.bouncycastle.org/java.html: The Bouncy Castle Crypto package is a Java implementation of cryptographic algorithms. This jar contains JCE provider and lightweight API for the Bouncy Castle Cryptography APIs for JDK 1.5 to JDK 1.8.
  • The Legion of the Bouncy Castle Inc. 
package org.bouncycastle.crypto.signers;

import java.math.BigInteger;
import java.security.SecureRandom;


Interface define calculators of K values for DSA/ECDSA.

/**
 * Interface define calculators of K values for DSA/ECDSA.
 */
public interface DSAKCalculator
{
    
Return true if this calculator is deterministic, false otherwise.

Returns:true if deterministic, otherwise false.
/**
     * Return true if this calculator is deterministic, false otherwise.
     *
     * @return true if deterministic, otherwise false.
     */
    boolean isDeterministic();

    
Non-deterministic initialiser.

Params:
  • n – the order of the DSA group.
  • random – a source of randomness.
/**
     * Non-deterministic initialiser.
     *
     * @param n the order of the DSA group.
     * @param random a source of randomness.
     */
    void init(BigInteger n, SecureRandom random);

    
Deterministic initialiser.

Params:
  • n – the order of the DSA group.
  • d – the DSA private value.
  • message – the message being signed.
/**
     * Deterministic initialiser.
     *
     * @param n the order of the DSA group.
     * @param d the DSA private value.
     * @param message the message being signed.
     */
    void init(BigInteger n, BigInteger d, byte[] message);

    
Return the next valid value of K.

Returns:a K value.
/**
     * Return the next valid value of K.
     *
     * @return a K value.
     */
    BigInteger nextK();
}