org.apache.xml.security.stax.impl.algorithms.DSAUtils Maven / Gradle / Ivy
/**
* 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.stax.impl.algorithms;
import java.io.IOException;
/**
* @author $Author: coheigea $
* @version $Revision: 1513098 $ $Date: 2013-08-12 11:28:33 +0100 (Mon, 12 Aug 2013) $
*/
public class DSAUtils {
/**
* 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
* @throws java.io.IOException
* @see 6.4.1 DSA
*/
public 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");
} else {
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
* @throws IOException
* @see 6.4.1 DSA
*/
public 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;
}
}