| /* DSASignature.java -- |
| Copyright (C) 1999, 2003, 2004 Free Software Foundation, Inc. |
| |
| This file is part of GNU Classpath. |
| |
| GNU Classpath is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 2, or (at your option) |
| any later version. |
| |
| GNU Classpath is distributed in the hope that it will be useful, but |
| WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with GNU Classpath; see the file COPYING. If not, write to the |
| Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA |
| 02111-1307 USA. |
| |
| Linking this library statically or dynamically with other modules is |
| making a combined work based on this library. Thus, the terms and |
| conditions of the GNU General Public License cover the whole |
| combination. |
| |
| As a special exception, the copyright holders of this library give you |
| permission to link this library with independent modules to produce an |
| executable, regardless of the license terms of these independent |
| modules, and to copy and distribute the resulting executable under |
| terms of your choice, provided that you also meet, for each linked |
| independent module, the terms and conditions of the license of that |
| module. An independent module is a module which is not derived from |
| or based on this library. If you modify this library, you may extend |
| this exception to your version of the library, but you are not |
| obligated to do so. If you do not wish to do so, delete this |
| exception statement from your version. */ |
| |
| |
| package gnu.java.security.provider; |
| |
| import gnu.java.security.der.DER; |
| import gnu.java.security.der.DERReader; |
| import gnu.java.security.der.DERValue; |
| import gnu.java.security.der.DERWriter; |
| |
| import java.io.ByteArrayOutputStream; |
| import java.io.IOException; |
| import java.math.BigInteger; |
| import java.security.InvalidAlgorithmParameterException; |
| import java.security.InvalidKeyException; |
| import java.security.InvalidParameterException; |
| import java.security.MessageDigest; |
| import java.security.NoSuchAlgorithmException; |
| import java.security.PrivateKey; |
| import java.security.PublicKey; |
| import java.security.SecureRandom; |
| import java.security.SignatureException; |
| import java.security.SignatureSpi; |
| import java.security.interfaces.DSAPrivateKey; |
| import java.security.interfaces.DSAPublicKey; |
| import java.security.spec.AlgorithmParameterSpec; |
| import java.util.ArrayList; |
| import java.util.Random; |
| |
| public class DSASignature extends SignatureSpi |
| { |
| private DSAPublicKey publicKey; |
| private DSAPrivateKey privateKey; |
| private final MessageDigest digest; |
| private final SecureRandom random; |
| |
| public DSASignature() throws NoSuchAlgorithmException |
| { |
| random = new SecureRandom(); |
| digest = MessageDigest.getInstance ("SHA1"); |
| } |
| |
| private void init() |
| { |
| digest.reset(); |
| } |
| |
| public void engineInitVerify (PublicKey publicKey) |
| throws InvalidKeyException |
| { |
| if (publicKey instanceof DSAPublicKey) |
| this.publicKey = (DSAPublicKey) publicKey; |
| else |
| throw new InvalidKeyException(); |
| init(); |
| } |
| |
| public void engineInitSign (PrivateKey privateKey) |
| throws InvalidKeyException |
| { |
| if (privateKey instanceof DSAPrivateKey) |
| this.privateKey = (DSAPrivateKey) privateKey; |
| else |
| throw new InvalidKeyException ("not a DSA private key"); |
| |
| init(); |
| } |
| |
| public void engineInitSign (PrivateKey privateKey, |
| SecureRandom random) |
| throws InvalidKeyException |
| { |
| if (privateKey instanceof DSAPrivateKey) |
| this.privateKey = (DSAPrivateKey) privateKey; |
| else |
| throw new InvalidKeyException ("not a DSA private key"); |
| |
| appRandom = random; |
| init(); |
| } |
| |
| public void engineUpdate(byte b) |
| throws SignatureException |
| { |
| digest.update (b); |
| } |
| |
| public void engineUpdate (byte[] b, int off, int len) |
| throws SignatureException |
| { |
| digest.update (b, off, len); |
| } |
| |
| public byte[] engineSign() throws SignatureException |
| { |
| if (privateKey == null) |
| throw new SignatureException ("not initialized for signing"); |
| |
| try |
| { |
| BigInteger g = privateKey.getParams().getG(); |
| BigInteger p = privateKey.getParams().getP(); |
| BigInteger q = privateKey.getParams().getQ(); |
| |
| BigInteger x = privateKey.getX(); |
| |
| BigInteger k = new BigInteger (159, appRandom != null ? appRandom : random); |
| |
| BigInteger r = g.modPow(k, p); |
| r = r.mod(q); |
| |
| byte bytes[] = digest.digest(); |
| BigInteger sha = new BigInteger (1, bytes); |
| |
| BigInteger s = sha.add (x.multiply (r)); |
| s = s.multiply (k.modInverse(q)).mod (q); |
| |
| ByteArrayOutputStream bout = new ByteArrayOutputStream(); |
| ArrayList seq = new ArrayList (2); |
| seq.add(0, new DERValue (DER.INTEGER, r)); |
| seq.add(1, new DERValue (DER.INTEGER, s)); |
| DERWriter.write (bout, new DERValue (DER.CONSTRUCTED | DER.SEQUENCE, seq)); |
| return bout.toByteArray(); |
| } |
| catch (IOException ioe) |
| { |
| SignatureException se = new SignatureException(); |
| se.initCause (ioe); |
| throw se; |
| } |
| catch (ArithmeticException ae) |
| { |
| SignatureException se = new SignatureException(); |
| se.initCause (ae); |
| throw se; |
| } |
| } |
| |
| public int engineSign (byte[] outbuf, int offset, int len) |
| throws SignatureException |
| { |
| byte tmp[] = engineSign(); |
| if (tmp.length > len) |
| throw new SignatureException ("output buffer too short"); |
| System.arraycopy (tmp, 0, outbuf, offset, tmp.length); |
| return tmp.length; |
| } |
| |
| public boolean engineVerify (byte[] sigBytes) |
| throws SignatureException |
| { |
| // Decode sigBytes from ASN.1 DER encoding |
| try |
| { |
| DERReader in = new DERReader (sigBytes); |
| DERValue val = in.read(); |
| if (!val.isConstructed()) |
| throw new SignatureException ("badly formed signature"); |
| BigInteger r = (BigInteger) in.read().getValue(); |
| BigInteger s = (BigInteger) in.read().getValue(); |
| |
| BigInteger g = publicKey.getParams().getG(); |
| BigInteger p = publicKey.getParams().getP(); |
| BigInteger q = publicKey.getParams().getQ(); |
| |
| BigInteger y = publicKey.getY(); |
| |
| BigInteger w = s.modInverse (q); |
| |
| byte bytes[] = digest.digest(); |
| BigInteger sha = new BigInteger (1, bytes); |
| |
| BigInteger u1 = w.multiply (sha).mod ( q ); |
| |
| BigInteger u2 = r.multiply (w).mod(q); |
| |
| BigInteger v = g.modPow (u1, p).multiply (y.modPow (u2, p)).mod (p).mod (q); |
| |
| if (v.equals (r)) |
| return true; |
| else |
| return false; |
| } |
| catch (IOException ioe) |
| { |
| SignatureException se = new SignatureException ("badly formed signature"); |
| se.initCause (ioe); |
| throw se; |
| } |
| } |
| |
| public void engineSetParameter (String param, |
| Object value) |
| throws InvalidParameterException |
| { |
| throw new InvalidParameterException(); |
| } |
| |
| public void engineSetParameter (AlgorithmParameterSpec params) |
| throws InvalidAlgorithmParameterException |
| { |
| throw new InvalidParameterException(); |
| |
| } |
| |
| public Object engineGetParameter (String param) |
| throws InvalidParameterException |
| { |
| throw new InvalidParameterException(); |
| } |
| |
| public Object clone() throws CloneNotSupportedException |
| { |
| return super.clone(); |
| } |
| } |