ecdsasigner.java

进行与数字证书相关开发必须的java源码

// Decompiled by Jad v1.5.7g. Copyright 2000 Pavel Kouznetsov.
// Jad home page: http://www.geocities.com/SiliconValley/Bridge/8617/jad.html
// Decompiler options: packimports(3) fieldsfirst ansi 
// Source File Name:   ECDSASigner.java

package jit.crypto.signers;

import jit.asn1.*;
import jit.crypto.CipherParameters;
import jit.crypto.DSA;
import jit.crypto.digests.SHA1Digest;
import jit.crypto.params.*;
import jit.math.BigInteger;
import jit.math.ec.*;
import jit.security.SecureRandom;

public class ECDSASigner
    implements ECConstants, DSA
{

    ECKeyParameters key;
    SecureRandom random;

    public ECDSASigner()
    {
    }

    public void init(boolean forSigning, CipherParameters param)
    {
        if(forSigning)
        {
            if(param instanceof ParametersWithRandom)
            {
                ParametersWithRandom rParam = (ParametersWithRandom)param;
                random = rParam.getRandom();
                key = (ECPrivateKeyParameters)rParam.getParameters();
            } else
            {
                random = new SecureRandom();
                key = (ECPrivateKeyParameters)param;
            }
        } else
        {
            key = (ECPublicKeyParameters)param;
        }
    }

    public BigInteger[] generateSignature(byte message[])
    {
        BigInteger e = new BigInteger(1, message);
        BigInteger n = key.getParameters().getN();
        BigInteger r = null;
        BigInteger s = null;
        do
        {
            BigInteger k = null;
            do
            {
                do
                {
                    k = new BigInteger(n.bitLength(), random);
                    k = k.mod(n);
                } while(k.equals(ECConstants.ZERO));
                ECPoint p = key.getParameters().getG().multiply(k);
                BigInteger x = p.getX().toBigInteger();
                r = x.mod(n);
            } while(r.equals(ECConstants.ZERO));
            BigInteger d = ((ECPrivateKeyParameters)key).getD();
            s = k.modInverse(n).multiply(e.add(d.multiply(r))).mod(n);
        } while(s.equals(ECConstants.ZERO));
        BigInteger res[] = new BigInteger[2];
        res[0] = r;
        res[1] = s;
        return res;
    }

    public DERObject signatureWithSHA(byte message[])
    {
        SHA1Digest sha = new SHA1Digest();
        byte digestedData[] = new byte[sha.getDigestSize()];
        sha.update(message, 0, message.length);
        sha.doFinal(digestedData, 0);
        BigInteger signedData[] = generateSignature(digestedData);
        ASN1EncodableVector v = new ASN1EncodableVector();
        v.add(new DERInteger(signedData[0]));
        v.add(new DERInteger(signedData[1]));
        return new DERSequence(v);
    }

    public boolean verifySignature(byte message[], BigInteger r, BigInteger s)
    {
        BigInteger e = new BigInteger(1, message);
        BigInteger n = key.getParameters().getN();
        if(r.compareTo(ECConstants.ONE) < 0 || r.compareTo(n) >= 0)
            return false;
        if(s.compareTo(ECConstants.ONE) < 0 || s.compareTo(n) >= 0)
        {
            return false;
        } else
        {
            BigInteger c = s.modInverse(n);
            BigInteger u1 = e.multiply(c).mod(n);
            BigInteger u2 = r.multiply(c).mod(n);
            ECPoint G = key.getParameters().getG();
            ECPoint Q = ((ECPublicKeyParameters)key).getQ();
            ECPoint point = G.multiply(u1).add(Q.multiply(u2));
            BigInteger v = point.getX().toBigInteger().mod(n);
            return v.equals(r);
        }
    }

    public boolean verifySignature(byte message[], DERObject obj)
    {
        if(!(obj instanceof DERSequence))
        {
            throw new IllegalArgumentException("unknown object in creat object");
        } else
        {
            DERSequence seq = (DERSequence)obj;
            DERInteger derR = (DERInteger)seq.getObjectAt(0);
            BigInteger r = derR.getValue();
            DERInteger derS = (DERInteger)seq.getObjectAt(1);
            BigInteger s = derS.getValue();
            return verifySignature(message, r, s);
        }
    }
}