| /* DHKeyPairX509Codec.java -- X.509 DER encoder/decoder for DH keys |
| Copyright (C) 2006 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., 51 Franklin Street, Fifth Floor, Boston, MA |
| 02110-1301 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.javax.crypto.key.dh; |
| |
| import java.io.ByteArrayOutputStream; |
| import java.io.IOException; |
| import java.math.BigInteger; |
| import java.security.InvalidParameterException; |
| import java.security.PrivateKey; |
| import java.security.PublicKey; |
| import java.util.ArrayList; |
| |
| import gnu.java.security.OID; |
| import gnu.java.security.Registry; |
| import gnu.java.security.der.BitString; |
| 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 gnu.java.security.key.IKeyPairCodec; |
| import gnu.java.security.util.DerUtil; |
| |
| public class DHKeyPairX509Codec |
| implements IKeyPairCodec |
| { |
| private static final OID DH_ALG_OID = new OID(Registry.DH_OID_STRING); |
| |
| // implicit 0-arguments constructor |
| |
| public int getFormatID() |
| { |
| return X509_FORMAT; |
| } |
| |
| /** |
| * Returns the DER-encoded form of the X.509 ASN.1 <i>SubjectPublicKeyInfo</i> |
| * representation of a DH public key. The ASN.1 specification, as defined in |
| * RFC-3280, and RFC-2459, is as follows: |
| * |
| * <pre> |
| * SubjectPublicKeyInfo ::= SEQUENCE { |
| * algorithm AlgorithmIdentifier, |
| * subjectPublicKey BIT STRING |
| * } |
| * |
| * AlgorithmIdentifier ::= SEQUENCE { |
| * algorithm OBJECT IDENTIFIER, |
| * parameters ANY DEFINED BY algorithm OPTIONAL |
| * } |
| * |
| * DhParams ::= SEQUENCE { |
| * p INTEGER, -- odd prime, p=jq +1 |
| * g INTEGER, -- generator, g |
| * q INTEGER -- factor of p-1 |
| * } |
| * </pre> |
| * |
| * <p>The <i>subjectPublicKey</i> field, which is a BIT STRING, contains the |
| * DER-encoded form of the DH public key as an INTEGER.</p> |
| * |
| * <pre> |
| * DHPublicKey ::= INTEGER -- public key, y = g^x mod p |
| * </pre> |
| * <p> |
| * <b>IMPORTANT</b>: with RI's {@link javax.crypto.spec.DHGenParameterSpec} |
| * and {@link javax.crypto.spec.DHParameterSpec} classes, we may end up with |
| * Diffie-Hellman keys that have a <code>null</code> for the <code>q</code> |
| * parameter. RFC-2631 DOES NOT allow for an <i>optional</i> value for that |
| * parameter, hence we replace such null values with <code>0</code>, and do |
| * the reverse in the corresponding decode method. |
| * |
| * @param key the {@link PublicKey} instance to encode. MUST be an instance of |
| * {@link GnuDHPublicKey}. |
| * @return the DER-encoded form of the ASN.1 representation of the |
| * <i>SubjectPublicKeyInfo</i> in an X.509 certificate. |
| * @throw InvalidParameterException if <code>key</code> is not an instance |
| * of {@link GnuDHPublicKey} or if an exception occurs during the |
| * marshalling process. |
| */ |
| public byte[] encodePublicKey(PublicKey key) |
| { |
| if (! (key instanceof GnuDHPublicKey)) |
| throw new InvalidParameterException("Wrong key type"); |
| |
| DERValue derOID = new DERValue(DER.OBJECT_IDENTIFIER, DH_ALG_OID); |
| |
| GnuDHPublicKey dhKey = (GnuDHPublicKey) key; |
| BigInteger p = dhKey.getParams().getP(); |
| BigInteger g = dhKey.getParams().getG(); |
| BigInteger q = dhKey.getQ(); |
| if (q == null) |
| q = BigInteger.ZERO; |
| BigInteger y = dhKey.getY(); |
| |
| DERValue derP = new DERValue(DER.INTEGER, p); |
| DERValue derG = new DERValue(DER.INTEGER, g); |
| DERValue derQ = new DERValue(DER.INTEGER, q); |
| |
| ArrayList params = new ArrayList(3); |
| params.add(derP); |
| params.add(derG); |
| params.add(derQ); |
| DERValue derParams = new DERValue(DER.CONSTRUCTED | DER.SEQUENCE, params); |
| |
| ArrayList algorithmID = new ArrayList(2); |
| algorithmID.add(derOID); |
| algorithmID.add(derParams); |
| DERValue derAlgorithmID = new DERValue(DER.CONSTRUCTED | DER.SEQUENCE, |
| algorithmID); |
| |
| DERValue derDHPublicKey = new DERValue(DER.INTEGER, y); |
| byte[] yBytes = derDHPublicKey.getEncoded(); |
| DERValue derSPK = new DERValue(DER.BIT_STRING, new BitString(yBytes)); |
| |
| ArrayList spki = new ArrayList(2); |
| spki.add(derAlgorithmID); |
| spki.add(derSPK); |
| DERValue derSPKI = new DERValue(DER.CONSTRUCTED | DER.SEQUENCE, spki); |
| |
| byte[] result; |
| ByteArrayOutputStream baos = new ByteArrayOutputStream(); |
| try |
| { |
| DERWriter.write(baos, derSPKI); |
| result = baos.toByteArray(); |
| } |
| catch (IOException x) |
| { |
| InvalidParameterException e = new InvalidParameterException(); |
| e.initCause(x); |
| throw e; |
| } |
| |
| return result; |
| } |
| |
| /** |
| * @throws InvalidParameterException ALWAYS. |
| */ |
| public byte[] encodePrivateKey(PrivateKey key) |
| { |
| throw new InvalidParameterException("Wrong format for private keys"); |
| } |
| |
| /** |
| * @param input the byte array to unmarshall into a valid DH |
| * {@link PublicKey} instance. MUST NOT be null. |
| * @return a new instance of a {@link GnuDHPublicKey} decoded from the |
| * <i>SubjectPublicKeyInfo</i> material in an X.509 certificate. |
| * @throw InvalidParameterException if an exception occurs during the |
| * unmarshalling process. |
| */ |
| public PublicKey decodePublicKey(byte[] input) |
| { |
| if (input == null) |
| throw new InvalidParameterException("Input bytes MUST NOT be null"); |
| |
| BigInteger p, g, q, y; |
| DERReader der = new DERReader(input); |
| try |
| { |
| DERValue derSPKI = der.read(); |
| DerUtil.checkIsConstructed(derSPKI, "Wrong SubjectPublicKeyInfo field"); |
| |
| DERValue derAlgorithmID = der.read(); |
| DerUtil.checkIsConstructed(derAlgorithmID, "Wrong AlgorithmIdentifier field"); |
| |
| DERValue derOID = der.read(); |
| if (! (derOID.getValue() instanceof OID)) |
| throw new InvalidParameterException("Wrong Algorithm field"); |
| |
| OID algOID = (OID) derOID.getValue(); |
| if (! algOID.equals(DH_ALG_OID)) |
| throw new InvalidParameterException("Unexpected OID: " + algOID); |
| |
| DERValue derParams = der.read(); |
| DerUtil.checkIsConstructed(derParams, "Wrong DH Parameters field"); |
| |
| DERValue val = der.read(); |
| DerUtil.checkIsBigInteger(val, "Wrong P field"); |
| p = (BigInteger) val.getValue(); |
| val = der.read(); |
| DerUtil.checkIsBigInteger(val, "Wrong G field"); |
| g = (BigInteger) val.getValue(); |
| val = der.read(); |
| DerUtil.checkIsBigInteger(val, "Wrong Q field"); |
| q = (BigInteger) val.getValue(); |
| if (q.compareTo(BigInteger.ZERO) == 0) |
| q = null; |
| |
| val = der.read(); |
| if (! (val.getValue() instanceof BitString)) |
| throw new InvalidParameterException("Wrong SubjectPublicKey field"); |
| |
| byte[] yBytes = ((BitString) val.getValue()).toByteArray(); |
| |
| DERReader dhPub = new DERReader(yBytes); |
| val = dhPub.read(); |
| DerUtil.checkIsBigInteger(val, "Wrong Y field"); |
| y = (BigInteger) val.getValue(); |
| } |
| catch (IOException x) |
| { |
| InvalidParameterException e = new InvalidParameterException(); |
| e.initCause(x); |
| throw e; |
| } |
| |
| return new GnuDHPublicKey(Registry.X509_ENCODING_ID, q, p, g, y); |
| } |
| |
| /** |
| * @throws InvalidParameterException ALWAYS. |
| */ |
| public PrivateKey decodePrivateKey(byte[] input) |
| { |
| throw new InvalidParameterException("Wrong format for private keys"); |
| } |
| } |