// ========================================================================
// Copyright 2001-2005 Mort Bay Consulting Pty. Ltd.
// ------------------------------------------------------------------------
// Licensed 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.mortbay.jetty.security;

/* --------------------------------------------------------------------- */
/**
 * Jetty Servlet SSL support utilities.
 * <p>
 * A collection of utilities required to support the SSL requirements of the Servlet 2.2 and 2.3
 * specs.
 * 
 * <p>
 * Used by the SSL listener classes.
 * 
 * @author Brett Sealey
 */
public class ServletSSL
{
    /* ------------------------------------------------------------ */
    /**
     * Given the name of a TLS/SSL cipher suite, return an int representing it effective stream
     * cipher key strength. i.e. How much entropy material is in the key material being fed into the
     * encryption routines.
     * 
     * <p>
     * This is based on the information on effective key lengths in RFC 2246 - The TLS Protocol
     * Version 1.0, Appendix C. CipherSuite definitions:
     * 
     * <pre>
     *                         Effective 
     *     Cipher       Type    Key Bits 
     * 		       	       
     *     NULL       * Stream     0     
     *     IDEA_CBC     Block    128     
     *     RC2_CBC_40 * Block     40     
     *     RC4_40     * Stream    40     
     *     RC4_128      Stream   128     
     *     DES40_CBC  * Block     40     
     *     DES_CBC      Block     56     
     *     3DES_EDE_CBC Block    168     
     * </pre>
     * 
     * @param cipherSuite String name of the TLS cipher suite.
     * @return int indicating the effective key entropy bit-length.
     */
    public static final int deduceKeyLength(String cipherSuite)
    {
        // Roughly ordered from most common to least common.
        if (cipherSuite == null)
            return 0;
        else if (cipherSuite.indexOf("WITH_AES_256_") >= 0)
            return 256;
        else if (cipherSuite.indexOf("WITH_RC4_128_") >= 0)
            return 128;
        else if (cipherSuite.indexOf("WITH_AES_128_") >= 0)
            return 128;
        else if (cipherSuite.indexOf("WITH_RC4_40_") >= 0)
            return 40;
        else if (cipherSuite.indexOf("WITH_3DES_EDE_CBC_") >= 0)
            return 168;
        else if (cipherSuite.indexOf("WITH_IDEA_CBC_") >= 0)
            return 128;
        else if (cipherSuite.indexOf("WITH_RC2_CBC_40_") >= 0)
            return 40;
        else if (cipherSuite.indexOf("WITH_DES40_CBC_") >= 0)
            return 40;
        else if (cipherSuite.indexOf("WITH_DES_CBC_") >= 0)
            return 56;
        else
            return 0;
    }
}
