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;


Generic signer interface for hash based and message recovery signers.

/**
 * Generic signer interface for hash based and message recovery signers.
 */
public interface Signer 
{
    
Initialise the signer for signing or verification.

Params:
  • forSigning – true if for signing, false otherwise
  • param – necessary parameters.
/**
     * Initialise the signer for signing or verification.
     * 
     * @param forSigning true if for signing, false otherwise
     * @param param necessary parameters.
     */
    public void init(boolean forSigning, CipherParameters param);

    
update the internal digest with the byte b

/**
     * update the internal digest with the byte b
     */
    public void update(byte b);

    
update the internal digest with the byte array in

/**
     * update the internal digest with the byte array in
     */
    public void update(byte[] in, int off, int len);

    
generate a signature for the message we've been loaded with using
the key we were initialised with.

/**
     * generate a signature for the message we've been loaded with using
     * the key we were initialised with.
     */
    public byte[] generateSignature()
        throws CryptoException, DataLengthException;

    
return true if the internal state represents the signature described
in the passed in array.

/**
     * return true if the internal state represents the signature described
     * in the passed in array.
     */
    public boolean verifySignature(byte[] signature);
    
    
reset the internal state

/**
     * reset the internal state
     */
    public void reset();
}