com.jingtum.core.bouncycastle.crypto.DSA Maven / Gradle / Ivy

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/*
 * Copyright www.jingtum.com Inc. 
 * 
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package com.jingtum.core.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);
}