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*
*
* Copyright 1990-2009 Sun Microsystems, Inc. All Rights Reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER
*
* This program 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.
*
* This program 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 at /legal/license.txt).
*
* 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 Sun Microsystems, Inc., 4150 Network Circle, Santa
* Clara, CA 95054 or visit www.sun.com if you need additional
* information or have any questions.
*/
package com.sun.midp.crypto;
/**
* Implements an abstract class that generalizes all ciphers. It is
* modelled after javax.crypto.Cipher.
*/
public abstract class Cipher {
/**
* Flag to indicate the current cipher algorithm is unknown.
*/
protected static final int MODE_UNINITIALIZED = 0;
/** Used in init to indicate encryption mode. */
public static final int ENCRYPT_MODE = 1;
/** Used in init to indicate decryption mode. */
public static final int DECRYPT_MODE = 2;
/** Protected constructor. */
protected Cipher() {
}
/**
* Called by the factory method to set the mode and padding parameters.
* Need because Class.newInstance does not take args.
*
* @param mode the chaining mode parsed from the transformation parameter
* of getInstance and upper cased
* @param padding the paddinge parsed from the transformation parameter of
* getInstance and upper cased
*
* @exception NoSuchPaddingException if <code>transformation</code>
* contains a padding scheme that is not available.
*/
protected abstract void setChainingModeAndPadding(String mode,
String padding) throws NoSuchPaddingException;
/**
* Generates a <code>Cipher</code> object that implements the specified
* transformation.
*
* @param transformation the name of the transformation, e.g.,
* <i>DES/CBC/PKCS5Padding</i>.
* See Appendix A in the
* <a href="../../../guide/security/jce/JCERefGuide.html#AppA">
* Java Cryptography Extension Reference Guide</a>
* for information about standard transformation names.
*
* @return a cipher that implements the requested transformation
*
* @exception NoSuchAlgorithmException if the specified transformation is
* not available
* @exception NoSuchPaddingException if <code>transformation</code>
* contains a padding scheme that is not available.
*/
public static final Cipher getInstance(String transformation)
throws NoSuchAlgorithmException, NoSuchPaddingException {
Cipher cipher = null;
String alg = ("" + transformation).toUpperCase().trim();
String chainingMode = "";
String padding = "";
if (alg.indexOf("/") != -1) {
int first = alg.indexOf("/");
int second = alg.indexOf("/", first + 1);
if (second == alg.lastIndexOf('/')) {
chainingMode = alg.substring(first + 1, second).trim();
padding = alg.substring(second + 1).trim();
alg = alg.substring(0, first).trim();
}
}
// We have the generic equivalent of RC4: ARC4 or ARCFOUR.
if (alg.equals("RC4") || alg.equals("ARCFOUR")) {
alg = "ARC4";
}
try {
Class cipherClass;
cipherClass = Class.forName("com.sun.midp.crypto." + alg);
cipher = (Cipher)cipherClass.newInstance();
} catch (Throwable t) {
throw new NoSuchAlgorithmException(transformation);
}
try {
cipher.setChainingModeAndPadding(chainingMode, padding);
} catch (IllegalArgumentException iae) {
// throw NoSuchAlgorithmException if the chainingMode is invalid
// (setChainingModeAndPadding() throws IllegalArgumentException
// in this case)
throw new NoSuchAlgorithmException(transformation);
}
return cipher;
}
/**
* Initializes this cipher with a key.
*
* <p>The cipher is initialized for one of the following operations:
* encryption, decryption, depending
* on the value of <code>opmode</code>.
*
* <p>If this cipher requires any algorithm parameters that cannot be
* derived from the given <code>key</code>, the underlying cipher
* implementation is supposed to generate the required parameters itself
* (using provider-specific default or random values) if it is being
* initialized for encryption, and raise an
* <code>InvalidKeyException</code> if it is being
* initialized for decryption.
*
* <p>Note that when a Cipher object is initialized, it loses all
* previously-acquired state. In other words, initializing a Cipher is
* equivalent to creating a new instance of that Cipher and initializing
* it.
*
* @param opmode the operation mode of this cipher (this is one of
* the following:
* <code>ENCRYPT_MODE</code> or <code>DECRYPT_MODE</code>)
* @param key the key
*
* @exception InvalidKeyException if the given key is inappropriate for
* initializing this cipher, or if this cipher is being initialized for
* decryption and requires algorithm parameters that cannot be
* determined from the given key, or if the given key has a keysize that
* exceeds the maximum allowable keysize.
*/
public void init(int opmode, Key key) throws InvalidKeyException {
try {
init(opmode, key, null);
} catch (InvalidAlgorithmParameterException e) {
throw new InvalidKeyException();
}
}
/**
* Initializes this cipher with a key and a set of algorithm
* parameters.
*
* <p>The cipher is initialized for one of the following operations:
* encryption or decryption depending
* on the value of <code>opmode</code>.
*
* <p>If this cipher requires any algorithm parameters and
* <code>params</code> is null, the underlying cipher implementation is
* supposed to generate the required parameters itself (using
* provider-specific default or random values) if it is being
* initialized for encryption, and raise an
* <code>InvalidAlgorithmParameterException</code> if it is being
* initialized for decryption.
*
* <p>Note that when a Cipher object is initialized, it loses all
* previously-acquired state. In other words, initializing a Cipher is
* equivalent to creating a new instance of that Cipher and initializing
* it.
*
* @param opmode the operation mode of this cipher (this is one of the
* following:
* <code>ENCRYPT_MODE</code> or <code>DECRYPT_MODE</code>)
* @param key the encryption key
* @param params the algorithm parameters
*
* @exception InvalidKeyException if the given key is inappropriate for
* initializing this cipher, or its keysize exceeds the maximum allowable
* keysize.
* @exception InvalidAlgorithmParameterException if the given algorithm
* parameters are inappropriate for this cipher,
* or this cipher is being initialized for decryption and requires
* algorithm parameters and <code>params</code> is null, or the given
* algorithm parameters imply a cryptographic strength that would exceed
* the legal limits.
*/
public abstract void init(int opmode, Key key, CryptoParameter params)
throws InvalidKeyException, InvalidAlgorithmParameterException;
/**
* 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> inclusive, are processed,
* and the result is stored in the <code>output</code> buffer, starting at
* <code>outputOffset</code> inclusive.
*
* <p>If the <code>output</code> buffer is too small to hold the result,
* a <code>ShortBufferException</code> is thrown. In this case, repeat this
* call with a larger output buffer.
*
* <p>If <code>inputLen</code> is zero, this method returns
* a length of zero.
*
* <p>Note: this method should be copy-safe, which means the
* <code>input</code> and <code>output</code> buffers can reference
* the same byte array and no unprocessed input data is overwritten
* when the result is copied into the output buffer.
*
* @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 IllegalStateException if this cipher is in a wrong state
* (e.g., has not been initialized)
* @exception ShortBufferException if the given output buffer is too small
* to hold the result
*/
public abstract int update(byte[] input, int inputOffset, int inputLen,
byte[] output, int outputOffset)
throws IllegalStateException, ShortBufferException;
/**
* 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> inclusive, 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> inclusive.
*
* <p>If the <code>output</code> buffer is too small to hold the result,
* a <code>ShortBufferException</code> is thrown. In this case, repeat this
* call with a larger output buffer.
*
* <p>Upon finishing, this method resets this cipher object to the state
* it was in when previously initialized via a call to <code>init</code>.
* That is, the object is reset and available to encrypt or decrypt
* (depending on the operation mode that was specified in the call to
* <code>init</code>) more data.
*
* <p>Note: if any exception is thrown, this cipher object may need to
* be reset before it can be used again.
*
* <p>Note: this method should be copy-safe, which means the
* <code>input</code> and <code>output</code> buffers can reference
* the same byte array and no unprocessed input data is overwritten
* when the result is copied into the output buffer.
*
* @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 IllegalStateException if this cipher is in a wrong state
* (e.g., has not been initialized)
* @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
*/
public abstract int doFinal(byte[] input, int inputOffset, int inputLen,
byte[] output, int outputOffset)
throws IllegalStateException, ShortBufferException,
IllegalBlockSizeException, BadPaddingException;
/**
* Returns the initialization vector (IV) in a new buffer.
* This is useful in the case where a random IV was created.
* @return the initialization vector in a new buffer,
* or <code>null</code> if the underlying algorithm does
* not use an IV, or if the IV has not yet been set.
*/
public byte[] getIV() {
return null;
}
}