SignatureECDSAN.java
/*
* Copyright (c) 2015-2018 ymnk, JCraft,Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification, are permitted
* provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this list of conditions
* and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice, this list of
* conditions and the following disclaimer in the documentation and/or other materials provided with
* the distribution.
*
* 3. The names of the authors may not be used to endorse or promote products derived from this
* software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL JCRAFT, INC. OR ANY CONTRIBUTORS TO THIS SOFTWARE BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
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package com.jcraft.jsch.jce;
import com.jcraft.jsch.Buffer;
import com.jcraft.jsch.SignatureECDSA;
import java.math.BigInteger;
import java.security.AlgorithmParameters;
import java.security.KeyFactory;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.Signature;
import java.security.spec.ECGenParameterSpec;
import java.security.spec.ECParameterSpec;
import java.security.spec.ECPoint;
import java.security.spec.ECPrivateKeySpec;
import java.security.spec.ECPublicKeySpec;
abstract class SignatureECDSAN implements SignatureECDSA {
Signature signature;
KeyFactory keyFactory;
abstract String getName();
@Override
public void init() throws Exception {
String name = getName();
String foo = "SHA256withECDSA";
if (name.equals("ecdsa-sha2-nistp384"))
foo = "SHA384withECDSA";
else if (name.equals("ecdsa-sha2-nistp521"))
foo = "SHA512withECDSA";
signature = Signature.getInstance(foo);
keyFactory = KeyFactory.getInstance("EC");
}
@Override
public void setPubKey(byte[] r, byte[] s) throws Exception {
// r and s must be unsigned values.
r = insert0(r);
s = insert0(s);
String name = "secp256r1";
if (r.length >= 64)
name = "secp521r1";
else if (r.length >= 48)
name = "secp384r1";
AlgorithmParameters param = AlgorithmParameters.getInstance("EC");
param.init(new ECGenParameterSpec(name));
ECParameterSpec ecparam = param.getParameterSpec(ECParameterSpec.class);
ECPoint w = new ECPoint(new BigInteger(1, r), new BigInteger(1, s));
PublicKey pubKey = keyFactory.generatePublic(new ECPublicKeySpec(w, ecparam));
signature.initVerify(pubKey);
}
@Override
public void setPrvKey(byte[] d) throws Exception {
// d must be unsigned value.
d = insert0(d);
String name = "secp256r1";
if (d.length >= 64)
name = "secp521r1";
else if (d.length >= 48)
name = "secp384r1";
AlgorithmParameters param = AlgorithmParameters.getInstance("EC");
param.init(new ECGenParameterSpec(name));
ECParameterSpec ecparam = param.getParameterSpec(ECParameterSpec.class);
BigInteger _d = new BigInteger(1, d);
PrivateKey prvKey = keyFactory.generatePrivate(new ECPrivateKeySpec(_d, ecparam));
signature.initSign(prvKey);
}
@Override
public byte[] sign() throws Exception {
byte[] sig = signature.sign();
// It seems that the output from SunEC is in ASN.1,
// so we have to convert it.
if (sig[0] == 0x30 && // in ASN.1
((sig[1] + 2 == sig.length)
|| ((sig[1] & 0x80) != 0 && (sig[2] & 0xff) + 3 == sig.length))) { // 2bytes for len
int index = 3;
if ((sig[1] & 0x80) != 0 && (sig[2] & 0xff) + 3 == sig.length)
index = 4;
byte[] r = new byte[sig[index]];
byte[] s = new byte[sig[index + 2 + sig[index]]];
System.arraycopy(sig, index + 1, r, 0, r.length);
System.arraycopy(sig, index + 3 + sig[index], s, 0, s.length);
r = chop0(r);
s = chop0(s);
Buffer buf = new Buffer();
buf.putMPInt(r);
buf.putMPInt(s);
sig = new byte[buf.getLength()];
buf.setOffSet(0);
buf.getByte(sig);
}
return sig;
}
@Override
public void update(byte[] foo) throws Exception {
signature.update(foo);
}
@Override
public boolean verify(byte[] sig) throws Exception {
// It seems that SunEC expects ASN.1 data,
// so we have to convert it.
if (!(sig[0] == 0x30 && // not in ASN.1
((sig[1] + 2 == sig.length)
|| ((sig[1] & 0x80) != 0 && (sig[2] & 0xff) + 3 == sig.length)))) {
Buffer b = new Buffer(sig);
b.getString(); // ecdsa-sha2-nistp256
b.getInt();
byte[] r = b.getMPInt();
byte[] s = b.getMPInt();
r = trimLeadingZeros(insert0(r));
s = trimLeadingZeros(insert0(s));
byte[] asn1 = null;
if (r.length < 64) {
asn1 = new byte[6 + r.length + s.length];
asn1[0] = (byte) 0x30;
asn1[1] = (byte) (4 + r.length + s.length);
asn1[2] = (byte) 0x02;
asn1[3] = (byte) r.length;
System.arraycopy(r, 0, asn1, 4, r.length);
asn1[r.length + 4] = (byte) 0x02;
asn1[r.length + 5] = (byte) s.length;
System.arraycopy(s, 0, asn1, (6 + r.length), s.length);
} else {
asn1 = new byte[6 + r.length + s.length + 1];
asn1[0] = (byte) 0x30;
asn1[1] = (byte) 0x81;
asn1[2] = (byte) (4 + r.length + s.length);
asn1[3] = (byte) 0x02;
asn1[4] = (byte) r.length;
System.arraycopy(r, 0, asn1, 5, r.length);
asn1[r.length + 5] = (byte) 0x02;
asn1[r.length + 6] = (byte) s.length;
System.arraycopy(s, 0, asn1, (7 + r.length), s.length);
}
sig = asn1;
}
return signature.verify(sig);
}
private static byte[] insert0(byte[] buf) {
if ((buf[0] & 0x80) == 0)
return buf;
byte[] tmp = new byte[buf.length + 1];
System.arraycopy(buf, 0, tmp, 1, buf.length);
Util.bzero(buf);
return tmp;
}
private static byte[] chop0(byte[] buf) {
if (buf[0] != 0)
return buf;
byte[] tmp = new byte[buf.length - 1];
System.arraycopy(buf, 1, tmp, 0, tmp.length);
Util.bzero(buf);
return tmp;
}
private static byte[] trimLeadingZeros(byte[] buf) {
if (buf.length < 2)
return buf;
int i = 0;
while (i < buf.length - 1) {
if (buf[i] == 0 && (buf[i + 1] & 0x80) == 0)
i++;
else
break;
}
if (i == 0)
return buf;
byte[] tmp = new byte[buf.length - i];
System.arraycopy(buf, i, tmp, 0, tmp.length);
Util.bzero(buf);
return tmp;
}
}