org.apache.xml.security.keys.content.x509.XMLX509SKI Maven / Gradle / Ivy

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Apache XML Security for Java supports XML-Signature Syntax and Processing, W3C Recommendation 12 February 2002, and XML Encryption Syntax and Processing, W3C Recommendation 10 December 2002. As of version 1.4, the library supports the standard Java API JSR-105: XML Digital Signature APIs.
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/**
 * 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.keys.content.x509;

import java.security.cert.X509Certificate;
import java.util.Arrays;

import org.apache.xml.security.exceptions.XMLSecurityException;
import org.apache.xml.security.utils.Base64;
import org.apache.xml.security.utils.Constants;
import org.apache.xml.security.utils.SignatureElementProxy;
import org.w3c.dom.Document;
import org.w3c.dom.Element;

/**
 * Handles SubjectKeyIdentifier (SKI) for X.509v3.
 *
 * @see 
 * Interface X509Extension
 */
public class XMLX509SKI extends SignatureElementProxy implements XMLX509DataContent {

    private static org.slf4j.Logger log =
        org.slf4j.LoggerFactory.getLogger(XMLX509SKI.class);

    /**
     * SubjectKeyIdentifier (id-ce-subjectKeyIdentifier) (2.5.29.14):
     * This extension identifies the public key being certified. It enables
     * distinct keys used by the same subject to be differentiated
     * (e.g., as key updating occurs).
     * 

     * A key identifier shall be unique with respect to all key identifiers
     * for the subject with which it is used. This extension is always non-critical.
     */
    public static final String SKI_OID = "2.5.29.14"; //NOPMD

    /**
     * Constructor X509SKI
     *
     * @param doc
     * @param skiBytes
     */
    public XMLX509SKI(Document doc, byte[] skiBytes) {
        super(doc);
        this.addBase64Text(skiBytes);
    }

    /**
     * Constructor XMLX509SKI
     *
     * @param doc
     * @param x509certificate
     * @throws XMLSecurityException
     */
    public XMLX509SKI(Document doc, X509Certificate x509certificate)
        throws XMLSecurityException {
        super(doc);
        this.addBase64Text(XMLX509SKI.getSKIBytesFromCert(x509certificate));
    }

    /**
     * Constructor XMLX509SKI
     *
     * @param element
     * @param baseURI
     * @throws XMLSecurityException
     */
    public XMLX509SKI(Element element, String baseURI) throws XMLSecurityException {
        super(element, baseURI);
    }

    /**
     * Method getSKIBytes
     *
     * @return the skibytes
     * @throws XMLSecurityException
     */
    public byte[] getSKIBytes() throws XMLSecurityException {
        return this.getBytesFromTextChild();
    }

    /**
     * Method getSKIBytesFromCert
     *
     * @param cert
     * @return ski bytes from the given certificate
     *
     * @throws XMLSecurityException
     * @see java.security.cert.X509Extension#getExtensionValue(java.lang.String)
     */
    public static byte[] getSKIBytesFromCert(X509Certificate cert)
        throws XMLSecurityException {

        if (cert.getVersion() < 3) {
            Object exArgs[] = { cert.getVersion() };
            throw new XMLSecurityException("certificate.noSki.lowVersion", exArgs);
        }

        /*
         * Gets the DER-encoded OCTET string for the extension value 
         * (extnValue) identified by the passed-in oid String. The oid 
         * string is represented by a set of positive whole numbers 
         * separated by periods.
         */
        byte[] extensionValue = cert.getExtensionValue(XMLX509SKI.SKI_OID);
        if (extensionValue == null) {
            throw new XMLSecurityException("certificate.noSki.null");
        }

        /**
         * Strip away first four bytes from the extensionValue 
         * The first two bytes are the tag and length of the extensionValue
         * OCTET STRING, and the next two bytes are the tag and length of
         * the ski OCTET STRING.
         */
        byte skidValue[] = new byte[extensionValue.length - 4];

        System.arraycopy(extensionValue, 4, skidValue, 0, skidValue.length);

        if (log.isDebugEnabled()) {
            log.debug("Base64 of SKI is " + Base64.encode(skidValue));
        }

        return skidValue;
    }

    /** @inheritDoc */
    public boolean equals(Object obj) {
        if (!(obj instanceof XMLX509SKI)) {
            return false;
        }

        XMLX509SKI other = (XMLX509SKI) obj;

        try {
            return Arrays.equals(other.getSKIBytes(), this.getSKIBytes());
        } catch (XMLSecurityException ex) {
            return false;
        }
    }

    public int hashCode() {
        int result = 17;
        try {
            byte[] bytes = getSKIBytes();
            for (int i = 0; i < bytes.length; i++) {
                result = 31 * result + bytes[i];
            }
        } catch (XMLSecurityException e) {
            if (log.isDebugEnabled()) {
                log.debug(e.getMessage(), e);
            }
        }
        return result;

    }

    /** @inheritDoc */
    public String getBaseLocalName() {
        return Constants._TAG_X509SKI;
    }
}