/*

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code 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

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

/*

 *

 *  (C) Copyright IBM Corp. 1999 All Rights Reserved.

 *  Copyright 1997 The Open Group Research Institute.  All rights reserved.

 */

package sun.security.krb5;

import sun.security.util.*;

import sun.security.krb5.internal.crypto.*;

import sun.security.krb5.internal.*;

import java.io.IOException;

import java.math.BigInteger;

/**

 * This class encapsulates Kerberos encrypted data. It allows

 * callers access to both the ASN.1 encoded form of the EncryptedData

 * type as well as the raw cipher text.

 */

public class EncryptedData implements Cloneable {

    int eType;

    Integer kvno; // optional

    byte[] cipher;

    byte[] plain; // not part of ASN.1 encoding

    // ----------------+-----------+----------+----------------+---------------

    // Encryption type |etype value|block size|minimum pad size|confounder size

    // ----------------+-----------+----------+----------------+---------------

    public static final int

        ETYPE_NULL        = 0;       // 1          0                0

    public static final int

        ETYPE_DES_CBC_CRC = 1;       // 8          4                8

    public static final int

        ETYPE_DES_CBC_MD4 = 2;       // 8          0                8

    public static final int

        ETYPE_DES_CBC_MD5 = 3;       // 8          0                8

    // draft-brezak-win2k-krb-rc4-hmac-04.txt

    public static final int

        ETYPE_ARCFOUR_HMAC = 23;     // 1

    // NOTE: the exportable RC4-HMAC is not supported;

    // it is no longer a usable encryption type

    public static final int

        ETYPE_ARCFOUR_HMAC_EXP = 24; // 1

     // draft-ietf-krb-wg-crypto-07.txt

    public static final int

        ETYPE_DES3_CBC_HMAC_SHA1_KD = 16; // 8     0                8

    // draft-raeburn-krb-rijndael-krb-07.txt

    public static final int

         ETYPE_AES128_CTS_HMAC_SHA1_96 = 17; // 16      0           16

    public static final int

         ETYPE_AES256_CTS_HMAC_SHA1_96 = 18; // 16      0           16

    /* used by self */

    private EncryptedData() {

    }

    public Object clone() {

        EncryptedData new_encryptedData = new EncryptedData();

        new_encryptedData.eType = eType;

        if (kvno != null) {

            new_encryptedData.kvno = new Integer(kvno.intValue());

        }

        if (cipher != null) {

            new_encryptedData.cipher = new byte[cipher.length];

            System.arraycopy(cipher, 0, new_encryptedData.cipher,

                             0, cipher.length);

        }

        return new_encryptedData;

    }

     // Used in JSSE (com.sun.net.ssl.internal.KerberosPreMasterSecret)

    public EncryptedData(

                         int new_eType,

                         Integer new_kvno,

                         byte[] new_cipher) {

        eType = new_eType;

        kvno = new_kvno;

        cipher = new_cipher;

    }

    /*

    // Not used.

    public EncryptedData(

                         EncryptionKey key,

                         byte[] plaintext)

        throws KdcErrException, KrbCryptoException {

        EType etypeEngine = EType.getInstance(key.getEType());

        cipher = etypeEngine.encrypt(plaintext, key.getBytes());

        eType = key.getEType();

        kvno = key.getKeyVersionNumber();

    }

    */

     // used in KrbApRep, KrbApReq, KrbAsReq, KrbCred, KrbPriv

     // Used in JSSE (com.sun.net.ssl.internal.KerberosPreMasterSecret)

    public EncryptedData(

                         EncryptionKey key,

                         byte[] plaintext,

                         int usage)

        throws KdcErrException, KrbCryptoException {

        EType etypeEngine = EType.getInstance(key.getEType());

        cipher = etypeEngine.encrypt(plaintext, key.getBytes(), usage);

        eType = key.getEType();

        kvno = key.getKeyVersionNumber();

    }

    /*

    // Not used.

    public EncryptedData(

                         EncryptionKey key,

                         byte[] ivec,

                         byte[] plaintext)

        throws KdcErrException, KrbCryptoException {

        EType etypeEngine = EType.getInstance(key.getEType());

        cipher = etypeEngine.encrypt(plaintext, key.getBytes(), ivec);

        eType = key.getEType();

        kvno = key.getKeyVersionNumber();

    }

    */

    /*

    // Not used.

    EncryptedData(

                  StringBuffer password,

                  byte[] plaintext)

        throws KdcErrException, KrbCryptoException {

        EncryptionKey key = new EncryptionKey(password);

        EType etypeEngine = EType.getInstance(key.getEType());

        cipher = etypeEngine.encrypt(plaintext, key.getBytes());

        eType = key.getEType();

        kvno = key.getKeyVersionNumber();

    }

    */

    // currently destructive on cipher

    public byte[] decrypt(

                          EncryptionKey key, int usage)

        throws KdcErrException, KrbApErrException, KrbCryptoException {

            if (eType != key.getEType()) {

                throw new KrbCryptoException(

                    "EncryptedData is encrypted using keytype " +

                    EType.toString(eType) +

                    " but decryption key is of type " +

                    EType.toString(key.getEType()));

            }

            EType etypeEngine = EType.getInstance(eType);

            plain = etypeEngine.decrypt(cipher, key.getBytes(), usage);

            cipher = null;

            return etypeEngine.decryptedData(plain);

        }

    /*

    // currently destructive on cipher

    // Not used.

    public byte[] decrypt(

                          EncryptionKey key,

                          byte[] ivec, int usage)

        throws KdcErrException, KrbApErrException, KrbCryptoException {

            // XXX check for matching eType and kvno here

            EType etypeEngine = EType.getInstance(eType);

            plain = etypeEngine.decrypt(cipher, key.getBytes(), ivec, usage);

            cipher = null;

            return etypeEngine.decryptedData(plain);

        }

    // currently destructive on cipher

    // Not used.

    byte[] decrypt(StringBuffer password)

        throws KdcErrException, KrbApErrException, KrbCryptoException {

            EncryptionKey key = new EncryptionKey(password);

            // XXX check for matching eType here

            EType etypeEngine = EType.getInstance(eType);

            plain = etypeEngine.decrypt(cipher, key.getBytes());

            cipher = null;

            return etypeEngine.decryptedData(plain);

        }

    */

    private byte[] decryptedData() throws KdcErrException {

        if (plain != null) {

            EType etypeEngine = EType.getInstance(eType);

            return etypeEngine.decryptedData(plain);

        }

        return null;

    }

    /**

     * Constructs an instance of EncryptedData type.

     * @param encoding a single DER-encoded value.

     * @exception Asn1Exception if an error occurs while decoding an

     * ASN1 encoded data.

     * @exception IOException if an I/O error occurs while reading encoded

     * data.

     *

     */

    /* Used by self */

    private EncryptedData(DerValue encoding)

        throws Asn1Exception, IOException {

        DerValue der = null;

        if (encoding.getTag() != DerValue.tag_Sequence) {

            throw new Asn1Exception(Krb5.ASN1_BAD_ID);

        }

        der = encoding.getData().getDerValue();

        if ((der.getTag() & (byte)0x1F) == (byte)0x00) {

            eType = (der.getData().getBigInteger()).intValue();

        } else {

            throw new Asn1Exception(Krb5.ASN1_BAD_ID);

        }

        if ((encoding.getData().peekByte() & 0x1F) == 1) {

            der = encoding.getData().getDerValue();

            int i = (der.getData().getBigInteger()).intValue();

            kvno = new Integer(i);

        } else {

            kvno = null;

        }

        der = encoding.getData().getDerValue();

        if ((der.getTag() & (byte)0x1F) == (byte)0x02) {

            cipher = der.getData().getOctetString();

        } else {

            throw new Asn1Exception(Krb5.ASN1_BAD_ID);

        }

        if (encoding.getData().available() > 0) {

            throw new Asn1Exception(Krb5.ASN1_BAD_ID);

        }

    }

    /**

     * Returns an ASN.1 encoded EncryptedData type.

     *

     * <xmp>

     * EncryptedData   ::= SEQUENCE {

     *     etype   [0] Int32 -- EncryptionType --,

     *     kvno    [1] UInt32 OPTIONAL,

     *     cipher  [2] OCTET STRING -- ciphertext

     * }

     * </xmp>

     *

     * <p>

     * This definition reflects the Network Working Group RFC 4120

     * specification available at

     * <a href="http://www.ietf.org/rfc/rfc4120.txt">

     * http://www.ietf.org/rfc/rfc4120.txt</a>.

     * <p>

     * @return byte array of encoded EncryptedData object.

     * @exception Asn1Exception if an error occurs while decoding an

     * ASN1 encoded data.

     * @exception IOException if an I/O error occurs while reading

     * encoded data.

     *

     */

    public byte[] asn1Encode() throws Asn1Exception, IOException {

        DerOutputStream bytes = new DerOutputStream();

        DerOutputStream temp = new DerOutputStream();

        temp.putInteger(BigInteger.valueOf(this.eType));

        bytes.write(DerValue.createTag(DerValue.TAG_CONTEXT,

                                       true, (byte)0x00), temp);

        temp = new DerOutputStream();

        if (kvno != null) {

            // encode as an unsigned integer (UInt32)

            temp.putInteger(BigInteger.valueOf(this.kvno.longValue()));

            bytes.write(DerValue.createTag(DerValue.TAG_CONTEXT,

                                           true, (byte)0x01), temp);

            temp = new DerOutputStream();

        }

        temp.putOctetString(this.cipher);

        bytes.write(DerValue.createTag(DerValue.TAG_CONTEXT, true,

                        (byte)0x02), temp);

        temp = new DerOutputStream();

        temp.write(DerValue.tag_Sequence, bytes);

        return temp.toByteArray();

    }

    /**

     * Parse (unmarshal) an EncryptedData from a DER input stream.  This form

     * parsing might be used when expanding a value which is part of

     * a constructed sequence and uses explicitly tagged type.

     *

     * @param data the Der input stream value, which contains one or more

     *        marshaled value.

     * @param explicitTag tag number.

     * @param optional indicate if this data field is optional

     * @exception Asn1Exception if an error occurs while decoding an

     * ASN1 encoded data.

     * @exception IOException if an I/O error occurs while reading

     * encoded data.

     * @return an instance of EncryptedData.

     *

     */

    public static EncryptedData parse(DerInputStream data,

                                      byte explicitTag,

                                      boolean optional)

        throws Asn1Exception, IOException {

        if ((optional) &&

            (((byte)data.peekByte() & (byte)0x1F) != explicitTag))

            return null;

        DerValue der = data.getDerValue();

        if (explicitTag != (der.getTag() & (byte)0x1F))  {

            throw new Asn1Exception(Krb5.ASN1_BAD_ID);

        } else {

            DerValue subDer = der.getData().getDerValue();

            return new EncryptedData(subDer);

        }

    }

    /**

     * @param data the decrypted data from decrypt().

     * @return the reset byte array which holds exactly one asn1 datum

     * including its tag and length.

     *

     */

        byte[]  bytes = null;

        // determine the data length and remove redundant paddings.

                }

        }

        return bytes;

    }

    public int getEType() {

        return eType;

    }

    public Integer getKeyVersionNumber() {

        return kvno;

    }

    /**

     * Returns the raw cipher text bytes, not in ASN.1 encoding.

     */

    public byte[] getBytes() {

        return cipher;

    }

}