package org.bouncycastle.crypto;import java.math.BigInteger;/** * interface for classes implementing algorithms modeled similar to the Digital Signature Alorithm. */public interface DSA{    /**     * initialise the signer for signature generation or signature     * verification.     *     * @param forSigning true if we are generating a signature, false     * otherwise.     * @param param key parameters for signature generation.     */    public void init(boolean forSigning, CipherParameters param);    /**     * sign the passed in message (usually the output of a hash function).     *     * @param message the message to be signed.     * @return two big integers representing the r and s values respectively.     */    public BigInteger[] generateSignature(byte[] message);    /**     * verify the message message against the signature values r and s.     *     * @param message the message that was supposed to have been signed.     * @param r the r signature value.     * @param s the s signature value.     */    public boolean verifySignature(byte[] message, BigInteger  r, BigInteger s);}