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package com.sun.crypto.provider;

import java.security.*;

import java.security.spec.*;

import javax.crypto.*;

import javax.crypto.spec.*;

/**

 * This class implements the DESede algorithm (DES-EDE, tripleDES) in

 * its various modes (<code>ECB</code>, <code>CFB</code>, <code>OFB</code>,

 * <code>CBC</code>, <code>PCBC</code>) and padding schemes

 * (<code>PKCS5Padding</code>, <code>NoPadding</code>,

 * <code>ISO10126Padding</code>).

 *

 * @author Gigi Ankeny

 *

 *

 * @see DESCipher

 */

public final class DESedeCipher extends CipherSpi {

    /*

     * internal CipherCore object which does the real work.

     */

    private CipherCore core = null;

    /**

     * Creates an instance of DESede cipher with default ECB mode and

     * PKCS5Padding.

     */

    public DESedeCipher() {

        core = new CipherCore(new DESedeCrypt(), DESConstants.DES_BLOCK_SIZE);

    }

    /**

     * Sets the mode of this cipher.

     *

     * @param mode the cipher mode

     *

     * @exception NoSuchAlgorithmException if the requested cipher mode does

     * not exist

     */

    protected void engineSetMode(String mode)

        throws NoSuchAlgorithmException {

        core.setMode(mode);

    }

    /**

     * Sets the padding mechanism of this cipher.

     *

     * @param padding the padding mechanism

     *

     * @exception NoSuchPaddingException if the requested padding mechanism

     * does not exist

     */

    protected void engineSetPadding(String paddingScheme)

        throws NoSuchPaddingException {

        core.setPadding(paddingScheme);

    }

    /**

     * Returns the block size (in bytes).

     *

     * @return the block size (in bytes), or 0 if the underlying algorithm is

     * not a block cipher

     */

    protected int engineGetBlockSize() {

        return DESConstants.DES_BLOCK_SIZE;

    }

    /**

     * Returns the length in bytes that an output buffer would need to be in

     * order to hold the result of the next <code>update</code> or

     * <code>doFinal</code> operation, given the input length

     * <code>inputLen</code> (in bytes).

     *

     * <p>This call takes into account any unprocessed (buffered) data from a

     * previous <code>update</code> call, and padding.

     *

     * <p>The actual output length of the next <code>update</code> or

     * <code>doFinal</code> call may be smaller than the length returned by

     * this method.

     *

     * @param inputLen the input length (in bytes)

     *

     * @return the required output buffer size (in bytes)

     */

    protected int engineGetOutputSize(int inputLen) {

        return core.getOutputSize(inputLen);

    }

    /**

     * Returns the initialization vector (IV) in a new buffer.

     *

     * <p>This is useful in the case where a random IV has been created

     * (see <a href = "#init">init</a>),

     * or in the context of password-based encryption or

     * decryption, where the IV is derived from a user-provided password.

     *

     * @return the initialization vector in a new buffer, or null if the

     * underlying algorithm does not use an IV, or if the IV has not yet

     * been set.

     */

    protected byte[] engineGetIV() {

        return core.getIV();

    }

    /**

     * Initializes this cipher with a key and a source of randomness.

     *

     * <p>The cipher is initialized for one of the following four operations:

     * encryption, decryption, key wrapping or key unwrapping, depending on

     * the value of <code>opmode</code>.

     *

     * <p>If this cipher requires an initialization vector (IV), it will get

     * it from <code>random</code>.

     * This behaviour should only be used in encryption or key wrapping

     * mode, however.

     * When initializing a cipher that requires an IV for decryption or

     * key unwrapping, the IV

     * (same IV that was used for encryption or key wrapping) must be provided

     * explicitly as a

     * parameter, in order to get the correct result.

     *

     * <p>This method also cleans existing buffer and other related state

     * information.

     *

     * @param opmode the operation mode of this cipher (this is one of

     * the following:

     * <code>ENCRYPT_MODE</code>, <code>DECRYPT_MODE</code>,

     * <code>WRAP_MODE</code> or <code>UNWRAP_MODE</code>)

     * @param key the secret key

     * @param random the source of randomness

     *

     * @exception InvalidKeyException if the given key is inappropriate for

     * initializing this cipher

     */

    protected void engineInit(int opmode, Key key, SecureRandom random)

        throws InvalidKeyException {

        core.init(opmode, key, random);

    }

    /**

     * Initializes this cipher with a key, a set of

     * algorithm parameters, and a source of randomness.

     *

     * <p>The cipher is initialized for one of the following four operations:

     * encryption, decryption, key wrapping or key unwrapping, depending on

     * the value of <code>opmode</code>.

     *

     * <p>If this cipher (including its underlying feedback or padding scheme)

     * requires any random bytes, it will get them from <code>random</code>.

     *

     * @param opmode the operation mode of this cipher (this is one of

     * the following:

     * <code>ENCRYPT_MODE</code>, <code>DECRYPT_MODE</code>,

     * <code>WRAP_MODE</code> or <code>UNWRAP_MODE</code>)

     * @param key the encryption key

     * @param params the algorithm parameters

     * @param random the source of randomness

     *

     * @exception InvalidKeyException if the given key is inappropriate for

     * initializing this cipher

     * @exception InvalidAlgorithmParameterException if the given algorithm

     * parameters are inappropriate for this cipher

     */

    protected void engineInit(int opmode, Key key,

                              AlgorithmParameterSpec params,

                              SecureRandom random)

        throws InvalidKeyException, InvalidAlgorithmParameterException {

        core.init(opmode, key, params, random);

    }

    protected void engineInit(int opmode, Key key,

                              AlgorithmParameters params,

                              SecureRandom random)

        throws InvalidKeyException, InvalidAlgorithmParameterException {

        core.init(opmode, key, params, random);

    }

    /**

     * Continues a multiple-part encryption or decryption operation

     * (depending on how this cipher was initialized), processing another data

     * part.

     *

     * <p>The first <code>inputLen</code> bytes in the <code>input</code>

     * buffer, starting at <code>inputOffset</code>, are processed, and the

     * result is stored in a new buffer.

     *

     * @param input the input buffer

     * @param inputOffset the offset in <code>input</code> where the input

     * starts

     * @param inputLen the input length

     *

     * @return the new buffer with the result

     *

     * @exception IllegalStateException if this cipher is in a wrong state

     * (e.g., has not been initialized)

     */

    protected byte[] engineUpdate(byte[] input, int inputOffset,

                                  int inputLen) {

        return core.update(input, inputOffset, inputLen);

    }

    /**

     * Continues a multiple-part encryption or decryption operation

     * (depending on how this cipher was initialized), processing another data

     * part.

     *

     * <p>The first <code>inputLen</code> bytes in the <code>input</code>

     * buffer, starting at <code>inputOffset</code>, are processed, and the

     * result is stored in the <code>output</code> buffer, starting at

     * <code>outputOffset</code>.

     *

     * @param input the input buffer

     * @param inputOffset the offset in <code>input</code> where the input

     * starts

     * @param inputLen the input length

     * @param output the buffer for the result

     * @param outputOffset the offset in <code>output</code> where the result

     * is stored

     *

     * @return the number of bytes stored in <code>output</code>

     *

     * @exception ShortBufferException if the given output buffer is too small

     * to hold the result

     */

    protected int engineUpdate(byte[] input, int inputOffset, int inputLen,

                               byte[] output, int outputOffset)

        throws ShortBufferException {

        return core.update(input, inputOffset, inputLen, output,

                           outputOffset);

    }

    /**

     * Encrypts or decrypts data in a single-part operation,

     * or finishes a multiple-part operation.

     * The data is encrypted or decrypted, depending on how this cipher was

     * initialized.

     *

     * <p>The first <code>inputLen</code> bytes in the <code>input</code>

     * buffer, starting at <code>inputOffset</code>, and any input bytes that

     * may have been buffered during a previous <code>update</code> operation,

     * are processed, with padding (if requested) being applied.

     * The result is stored in a new buffer.

     *

     * <p>The cipher is reset to its initial state (uninitialized) after this

     * call.

     *

     * @param input the input buffer

     * @param inputOffset the offset in <code>input</code> where the input

     * starts

     * @param inputLen the input length

     *

     * @return the new buffer with the result

     *

     * @exception IllegalBlockSizeException if this cipher is a block cipher,

     * no padding has been requested (only in encryption mode), and the total

     * input length of the data processed by this cipher is not a multiple of

     * block size

     * @exception BadPaddingException if this cipher is in decryption mode,

     * and (un)padding has been requested, but the decrypted data is not

     * bounded by the appropriate padding bytes

     */

    protected byte[] engineDoFinal(byte[] input, int inputOffset,

                                   int inputLen)

        throws IllegalBlockSizeException, BadPaddingException {

        return core.doFinal(input, inputOffset, inputLen);

    }

    /**

     * Encrypts or decrypts data in a single-part operation,

     * or finishes a multiple-part operation.

     * The data is encrypted or decrypted, depending on how this cipher was

     * initialized.

     *

     * <p>The first <code>inputLen</code> bytes in the <code>input</code>

     * buffer, starting at <code>inputOffset</code>, and any input bytes that

     * may have been buffered during a previous <code>update</code> operation,

     * are processed, with padding (if requested) being applied.

     * The result is stored in the <code>output</code> buffer, starting at

     * <code>outputOffset</code>.

     *

     * <p>The cipher is reset to its initial state (uninitialized) after this

     * call.

     *

     * @param input the input buffer

     * @param inputOffset the offset in <code>input</code> where the input

     * starts

     * @param inputLen the input length

     * @param output the buffer for the result

     * @param outputOffset the offset in <code>output</code> where the result

     * is stored

     *

     * @return the number of bytes stored in <code>output</code>

     *

     * @exception IllegalBlockSizeException if this cipher is a block cipher,

     * no padding has been requested (only in encryption mode), and the total

     * input length of the data processed by this cipher is not a multiple of

     * block size

     * @exception ShortBufferException if the given output buffer is too small

     * to hold the result

     * @exception BadPaddingException if this cipher is in decryption mode,

     * and (un)padding has been requested, but the decrypted data is not

     * bounded by the appropriate padding bytes

     */

    protected int engineDoFinal(byte[] input, int inputOffset, int inputLen,

                                byte[] output, int outputOffset)

        throws IllegalBlockSizeException, ShortBufferException,

               BadPaddingException {

        return core.doFinal(input, inputOffset, inputLen, output,

                            outputOffset);

    }

    /**

     * Returns the parameters used with this cipher.

     *

     * <p>The returned parameters may be the same that were used to initialize

     * this cipher, or may contain the default set of parameters or a set of

     * randomly generated parameters used by the underlying cipher

     * implementation (provided that the underlying cipher implementation

     * uses a default set of parameters or creates new parameters if it needs

     * parameters but was not initialized with any).

     *

     * @return the parameters used with this cipher, or null if this cipher

     * does not use any parameters.

     */

    protected AlgorithmParameters engineGetParameters() {

        return core.getParameters("DESede");

    }

    /**

     *  Returns the key size of the given key object.

     *

     * @param key the key object.

     *

     * @return the "effective" key size of the given key object.

     *

     * @exception InvalidKeyException if <code>key</code> is invalid.

     */

    protected int engineGetKeySize(Key key) throws InvalidKeyException {

        byte[] encoded = key.getEncoded();

        if (encoded.length != 24) {

            throw new InvalidKeyException("Invalid key length: " +

                encoded.length + " bytes");

        }

        // Return the effective key length

        return 112;

    }

    /**

     * Wrap a key.

     *

     * @param key the key to be wrapped.

     *

     * @return the wrapped key.

     *

     * @exception IllegalBlockSizeException if this cipher is a block

     * cipher, no padding has been requested, and the length of the

     * encoding of the key to be wrapped is not a

     * multiple of the block size.

     *

     * @exception InvalidKeyException if it is impossible or unsafe to

     * wrap the key with this cipher (e.g., a hardware protected key is

     * being passed to a software only cipher).

     */

    protected byte[] engineWrap(Key key)

        throws IllegalBlockSizeException, InvalidKeyException {

        return core.wrap(key);

    }

    /**

     * Unwrap a previously wrapped key.

     *

     * @param wrappedKey the key to be unwrapped.

     *

     * @param wrappedKeyAlgorithm the algorithm the wrapped key is for.

     *

     * @param wrappedKeyType the type of the wrapped key.

     * This is one of <code>Cipher.SECRET_KEY</code>,

     * <code>Cipher.PRIVATE_KEY</code>, or <code>Cipher.PUBLIC_KEY</code>.

     *

     * @return the unwrapped key.

     *

     * @exception NoSuchAlgorithmException if no installed providers

     * can create keys of type <code>wrappedKeyType</code> for the

     * <code>wrappedKeyAlgorithm</code>.

     *

     * @exception InvalidKeyException if <code>wrappedKey</code> does not

     * represent a wrapped key of type <code>wrappedKeyType</code> for

     * the <code>wrappedKeyAlgorithm</code>.

     */

    protected Key engineUnwrap(byte[] wrappedKey,

                                     String wrappedKeyAlgorithm,

                                     int wrappedKeyType)

        throws InvalidKeyException, NoSuchAlgorithmException {

        return core.unwrap(wrappedKey, wrappedKeyAlgorithm,

                           wrappedKeyType);

    }

}