Java tutorial
/** * 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 org.apache.xml.security.algorithms.implementations; import java.io.IOException; import java.security.InvalidAlgorithmParameterException; import java.security.InvalidKeyException; import java.security.Key; import java.security.PrivateKey; import java.security.PublicKey; import java.security.SecureRandom; import java.security.Signature; import java.security.SignatureException; import java.security.spec.AlgorithmParameterSpec; import org.apache.xml.security.algorithms.JCEMapper; import org.apache.xml.security.algorithms.SignatureAlgorithmSpi; import org.apache.xml.security.signature.XMLSignatureException; import org.apache.xml.security.utils.Base64; import org.apache.xml.security.utils.Constants; public class SignatureDSA extends SignatureAlgorithmSpi { /** {@link org.apache.commons.logging} logging facility */ private static org.apache.commons.logging.Log log = org.apache.commons.logging.LogFactory .getLog(SignatureDSA.class); /** Field URI */ public static final String URI = Constants.SignatureSpecNS + "dsa-sha1"; /** Field algorithm */ private java.security.Signature signatureAlgorithm = null; /** * Method engineGetURI * * @inheritDoc */ protected String engineGetURI() { return SignatureDSA.URI; } /** * Constructor SignatureDSA * * @throws XMLSignatureException */ public SignatureDSA() throws XMLSignatureException { String algorithmID = JCEMapper.translateURItoJCEID(SignatureDSA.URI); if (log.isDebugEnabled()) { log.debug("Created SignatureDSA using " + algorithmID); } String provider = JCEMapper.getProviderId(); try { if (provider == null) { this.signatureAlgorithm = Signature.getInstance(algorithmID); } else { this.signatureAlgorithm = Signature.getInstance(algorithmID, provider); } } catch (java.security.NoSuchAlgorithmException ex) { Object[] exArgs = { algorithmID, ex.getLocalizedMessage() }; throw new XMLSignatureException("algorithms.NoSuchAlgorithm", exArgs); } catch (java.security.NoSuchProviderException ex) { Object[] exArgs = { algorithmID, ex.getLocalizedMessage() }; throw new XMLSignatureException("algorithms.NoSuchAlgorithm", exArgs); } } /** * @inheritDoc */ protected void engineSetParameter(AlgorithmParameterSpec params) throws XMLSignatureException { try { this.signatureAlgorithm.setParameter(params); } catch (InvalidAlgorithmParameterException ex) { throw new XMLSignatureException("empty", ex); } } /** * @inheritDoc */ protected boolean engineVerify(byte[] signature) throws XMLSignatureException { try { if (log.isDebugEnabled()) { log.debug("Called DSA.verify() on " + Base64.encode(signature)); } byte[] jcebytes = SignatureDSA.convertXMLDSIGtoASN1(signature); return this.signatureAlgorithm.verify(jcebytes); } catch (SignatureException ex) { throw new XMLSignatureException("empty", ex); } catch (IOException ex) { throw new XMLSignatureException("empty", ex); } } /** * @inheritDoc */ protected void engineInitVerify(Key publicKey) throws XMLSignatureException { if (!(publicKey instanceof PublicKey)) { String supplied = publicKey.getClass().getName(); String needed = PublicKey.class.getName(); Object exArgs[] = { supplied, needed }; throw new XMLSignatureException("algorithms.WrongKeyForThisOperation", exArgs); } try { this.signatureAlgorithm.initVerify((PublicKey) publicKey); } catch (InvalidKeyException ex) { // reinstantiate Signature object to work around bug in JDK // see: http://bugs.sun.com/view_bug.do?bug_id=4953555 Signature sig = this.signatureAlgorithm; try { this.signatureAlgorithm = Signature.getInstance(signatureAlgorithm.getAlgorithm()); } catch (Exception e) { // this shouldn't occur, but if it does, restore previous // Signature if (log.isDebugEnabled()) { log.debug("Exception when reinstantiating Signature:" + e); } this.signatureAlgorithm = sig; } throw new XMLSignatureException("empty", ex); } } /** * @inheritDoc */ protected byte[] engineSign() throws XMLSignatureException { try { byte jcebytes[] = this.signatureAlgorithm.sign(); return SignatureDSA.convertASN1toXMLDSIG(jcebytes); } catch (IOException ex) { throw new XMLSignatureException("empty", ex); } catch (SignatureException ex) { throw new XMLSignatureException("empty", ex); } } /** * @inheritDoc */ protected void engineInitSign(Key privateKey, SecureRandom secureRandom) throws XMLSignatureException { if (!(privateKey instanceof PrivateKey)) { String supplied = privateKey.getClass().getName(); String needed = PrivateKey.class.getName(); Object exArgs[] = { supplied, needed }; throw new XMLSignatureException("algorithms.WrongKeyForThisOperation", exArgs); } try { this.signatureAlgorithm.initSign((PrivateKey) privateKey, secureRandom); } catch (InvalidKeyException ex) { throw new XMLSignatureException("empty", ex); } } /** * @inheritDoc */ protected void engineInitSign(Key privateKey) throws XMLSignatureException { if (!(privateKey instanceof PrivateKey)) { String supplied = privateKey.getClass().getName(); String needed = PrivateKey.class.getName(); Object exArgs[] = { supplied, needed }; throw new XMLSignatureException("algorithms.WrongKeyForThisOperation", exArgs); } try { this.signatureAlgorithm.initSign((PrivateKey) privateKey); } catch (InvalidKeyException ex) { throw new XMLSignatureException("empty", ex); } } /** * @inheritDoc */ protected void engineUpdate(byte[] input) throws XMLSignatureException { try { this.signatureAlgorithm.update(input); } catch (SignatureException ex) { throw new XMLSignatureException("empty", ex); } } /** * @inheritDoc */ protected void engineUpdate(byte input) throws XMLSignatureException { try { this.signatureAlgorithm.update(input); } catch (SignatureException ex) { throw new XMLSignatureException("empty", ex); } } /** * @inheritDoc */ protected void engineUpdate(byte buf[], int offset, int len) throws XMLSignatureException { try { this.signatureAlgorithm.update(buf, offset, len); } catch (SignatureException ex) { throw new XMLSignatureException("empty", ex); } } /** * Method engineGetJCEAlgorithmString * * @inheritDoc */ protected String engineGetJCEAlgorithmString() { return this.signatureAlgorithm.getAlgorithm(); } /** * Method engineGetJCEProviderName * * @inheritDoc */ protected String engineGetJCEProviderName() { return this.signatureAlgorithm.getProvider().getName(); } /** * Converts an ASN.1 DSA value to a XML Signature DSA Value. * * The JAVA JCE DSA Signature algorithm creates ASN.1 encoded (r,s) value * pairs; the XML Signature requires the core BigInteger values. * * @param asn1Bytes * @return the decode bytes * * @throws IOException * @see <A HREF="http://www.w3.org/TR/xmldsig-core/#dsa-sha1">6.4.1 DSA</A> */ private static byte[] convertASN1toXMLDSIG(byte asn1Bytes[]) throws IOException { byte rLength = asn1Bytes[3]; int i; for (i = rLength; (i > 0) && (asn1Bytes[(4 + rLength) - i] == 0); i--) ; byte sLength = asn1Bytes[5 + rLength]; int j; for (j = sLength; (j > 0) && (asn1Bytes[(6 + rLength + sLength) - j] == 0); j--) ; if ((asn1Bytes[0] != 48) || (asn1Bytes[1] != asn1Bytes.length - 2) || (asn1Bytes[2] != 2) || (i > 20) || (asn1Bytes[4 + rLength] != 2) || (j > 20)) { throw new IOException("Invalid ASN.1 format of DSA signature"); } byte xmldsigBytes[] = new byte[40]; System.arraycopy(asn1Bytes, (4 + rLength) - i, xmldsigBytes, 20 - i, i); System.arraycopy(asn1Bytes, (6 + rLength + sLength) - j, xmldsigBytes, 40 - j, j); return xmldsigBytes; } /** * Converts a XML Signature DSA Value to an ASN.1 DSA value. * * The JAVA JCE DSA Signature algorithm creates ASN.1 encoded (r,s) value * pairs; the XML Signature requires the core BigInteger values. * * @param xmldsigBytes * @return the encoded ASN.1 bytes * * @throws IOException * @see <A HREF="http://www.w3.org/TR/xmldsig-core/#dsa-sha1">6.4.1 DSA</A> */ private static byte[] convertXMLDSIGtoASN1(byte xmldsigBytes[]) throws IOException { if (xmldsigBytes.length != 40) { throw new IOException("Invalid XMLDSIG format of DSA signature"); } int i; for (i = 20; (i > 0) && (xmldsigBytes[20 - i] == 0); i--) ; int j = i; if (xmldsigBytes[20 - i] < 0) { j += 1; } int k; for (k = 20; (k > 0) && (xmldsigBytes[40 - k] == 0); k--) ; int l = k; if (xmldsigBytes[40 - k] < 0) { l += 1; } byte asn1Bytes[] = new byte[6 + j + l]; asn1Bytes[0] = 48; asn1Bytes[1] = (byte) (4 + j + l); asn1Bytes[2] = 2; asn1Bytes[3] = (byte) j; System.arraycopy(xmldsigBytes, 20 - i, asn1Bytes, (4 + j) - i, i); asn1Bytes[4 + j] = 2; asn1Bytes[5 + j] = (byte) l; System.arraycopy(xmldsigBytes, 40 - k, asn1Bytes, (6 + j + l) - k, k); return asn1Bytes; } /** * Method engineSetHMACOutputLength * * @param HMACOutputLength * @throws XMLSignatureException */ protected void engineSetHMACOutputLength(int HMACOutputLength) throws XMLSignatureException { throw new XMLSignatureException("algorithms.HMACOutputLengthOnlyForHMAC"); } /** * Method engineInitSign * * @param signingKey * @param algorithmParameterSpec * @throws XMLSignatureException */ protected void engineInitSign(Key signingKey, AlgorithmParameterSpec algorithmParameterSpec) throws XMLSignatureException { throw new XMLSignatureException("algorithms.CannotUseAlgorithmParameterSpecOnDSA"); } }