/* * Copyright (c) 2004, 2009, Oracle and/or its affiliates. All rights reserved. * 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. */ package com.sun.crypto.provider; import java.util.Arrays;import java.security.*;import java.security.spec.*;import javax.crypto.*;import javax.crypto.spec.*; /** * This class implements the AES KeyWrap algorithm as defined * in <a href=http://www.w3.org/TR/xmlenc-core/#sec-Alg-SymmetricKeyWrap> * "XML Encryption Syntax and Processing" section 5.6.3 "AES Key Wrap". * Note: only <code>ECB</code> mode and <code>NoPadding</code> padding * can be used for this algorithm. * * @author Valerie Peng * * * @see AESCipher */public final class AESWrapCipher extends CipherSpi {     private static final byte[] IV = {        (byte) 0xA6, (byte) 0xA6, (byte) 0xA6, (byte) 0xA6,        (byte) 0xA6, (byte) 0xA6, (byte) 0xA6, (byte) 0xA6    };     private static final int blksize = AESConstants.AES_BLOCK_SIZE;     /*     * internal cipher object which does the real work.     */    private AESCrypt cipher;     /*     * are we encrypting or decrypting?     */    private boolean decrypting = false;     /**     * Creates an instance of AES KeyWrap cipher with default     * mode, i.e. "ECB" and padding scheme, i.e. "NoPadding".     */    public AESWrapCipher() {        cipher = new AESCrypt();    }     /**     * Sets the mode of this cipher. Only "ECB" mode is accepted for this     * cipher.     *     * @param mode the cipher mode     *     * @exception NoSuchAlgorithmException if the requested cipher mode     * is not "ECB".     */    protected void engineSetMode(String mode)        throws NoSuchAlgorithmException {        if (!mode.equalsIgnoreCase("ECB")) {            throw new NoSuchAlgorithmException(mode + " cannot be used");        }    }     /**     * Sets the padding mechanism of this cipher. Only "NoPadding" schmem     * is accepted for this cipher.     *     * @param padding the padding mechanism     *     * @exception NoSuchPaddingException if the requested padding mechanism     * is not "NoPadding".     */    protected void engineSetPadding(String padding)        throws NoSuchPaddingException {        if (!padding.equalsIgnoreCase("NoPadding")) {            throw new NoSuchPaddingException(padding + " cannot be used");        }    }     /**     * Returns the block size (in bytes). i.e. 16 bytes.     *     * @return the block size (in bytes), i.e. 16 bytes.     */    protected int engineGetBlockSize() {        return blksize;    }     /**     * Returns the length in bytes that an output buffer would need to be     * given the input length <code>inputLen</code> (in bytes).     *     * <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) {        // can only return an upper-limit if not initialized yet.        int result = 0;        if (decrypting) {            result = inputLen - 8;        } else {            result = inputLen + 8;        }        return (result < 0? 0:result);    }     /**     * Returns the initialization vector (IV) which is null for this cipher.     *     * @return null for this cipher.     */    protected byte[] engineGetIV() {        return null;    }     /**     * Initializes this cipher with a key and a source of randomness.     *     * <p>The cipher only supports the following two operation modes:<b>     * Cipher.WRAP_MODE, and <b>     * Cipher.UNWRAP_MODE.     * <p>For modes other than the above two, UnsupportedOperationException     * will be thrown.     *     * @param opmode the operation mode of this cipher. Only     * <code>WRAP_MODE</code> or <code>UNWRAP_MODE</code>) are accepted.     * @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 {        if (opmode == Cipher.WRAP_MODE) {            decrypting = false;        } else if (opmode == Cipher.UNWRAP_MODE) {            decrypting = true;        } else {            throw new UnsupportedOperationException("This cipher can " +                "only be used for key wrapping and unwrapping");        }        cipher.init(decrypting, key.getAlgorithm(), key.getEncoded());    }     /**     * Initializes this cipher with a key, a set of algorithm parameters,     * and a source of randomness.     *     * <p>The cipher only supports the following two operation modes:<b>     * Cipher.WRAP_MODE, and <b>     * Cipher.UNWRAP_MODE.     * <p>For modes other than the above two, UnsupportedOperationException     * will be thrown.     *     * @param opmode the operation mode of this cipher. Only     * <code>WRAP_MODE</code> or <code>UNWRAP_MODE</code>) are accepted.     * @param key the secret key.     * @param params the algorithm parameters; must be null for this cipher.     * @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 is not null.     */    protected void engineInit(int opmode, Key key,                              AlgorithmParameterSpec params,                              SecureRandom random)        throws InvalidKeyException, InvalidAlgorithmParameterException {        if (params != null) {            throw new InvalidAlgorithmParameterException("This cipher " +                "does not accept any parameters");        }        engineInit(opmode, key, random);    }     /**     * Initializes this cipher with a key, a set of algorithm parameters,     * and a source of randomness.     *     * <p>The cipher only supports the following two operation modes:<b>     * Cipher.WRAP_MODE, and <b>     * Cipher.UNWRAP_MODE.     * <p>For modes other than the above two, UnsupportedOperationException     * will be thrown.     *     * @param opmode the operation mode of this cipher. Only     * <code>WRAP_MODE</code> or <code>UNWRAP_MODE</code>) are accepted.     * @param key the secret key.     * @param params the algorithm parameters; must be null for this cipher.     * @param random the source of randomness.     *     * @exception InvalidKeyException if the given key is inappropriate.     * @exception InvalidAlgorithmParameterException if the given algorithm     * parameters is not null.     */    protected void engineInit(int opmode, Key key,                              AlgorithmParameters params,                              SecureRandom random)        throws InvalidKeyException, InvalidAlgorithmParameterException {        if (params != null) {            throw new InvalidAlgorithmParameterException("This cipher " +                "does not accept any parameters");        }        engineInit(opmode, key, random);    }     /**     * This operation is not supported by this cipher.     * Since it's impossible to initialize this cipher given the     * current Cipher.engineInit(...) implementation,     * IllegalStateException will always be thrown upon invocation.     *     * @param in the input buffer.     * @param inOffset the offset in <code>in</code> where the input     * starts.     * @param inLen the input length.     *     * @return n/a.     *     * @exception IllegalStateException upon invocation of this method.     */    protected byte[] engineUpdate(byte[] in, int inOffset, int inLen) {        throw new IllegalStateException("Cipher has not been initialized");    }     /**     * This operation is not supported by this cipher.     * Since it's impossible to initialize this cipher given the     * current Cipher.engineInit(...) implementation,     * IllegalStateException will always be thrown upon invocation.     *     * @param in the input buffer.     * @param inOffset the offset in <code>in</code> where the input     * starts.     * @param inLen the input length.     * @param out the buffer for the result.     * @param outOffset the offset in <code>out</code> where the result     * is stored.     *     * @return n/a.     *     * @exception IllegalStateException upon invocation of this method.     */    protected int engineUpdate(byte[] in, int inOffset, int inLen,                               byte[] out, int outOffset)        throws ShortBufferException {        throw new IllegalStateException("Cipher has not been initialized");    }     /**     * This operation is not supported by this cipher.     * Since it's impossible to initialize this cipher given the     * current Cipher.engineInit(...) implementation,     * IllegalStateException will always be thrown upon invocation.     *     * @param in the input buffer     * @param inOffset the offset in <code>in</code> where the input     * starts     * @param inLen the input length.     *     * @return n/a.     *     * @exception IllegalStateException upon invocation of this method.     */    protected byte[] engineDoFinal(byte[] input, int inputOffset,                                   int inputLen)        throws IllegalBlockSizeException, BadPaddingException {        throw new IllegalStateException("Cipher has not been initialized");    }     /**     * This operation is not supported by this cipher.     * Since it's impossible to initialize this cipher given the     * current Cipher.engineInit(...) implementation,     * IllegalStateException will always be thrown upon invocation.     *     * @param in the input buffer.     * @param inOffset the offset in <code>in</code> where the input     * starts.     * @param inLen the input length.     * @param out the buffer for the result.     * @param outOffset the ofset in <code>out</code> where the result     * is stored.     *     * @return n/a.     *     * @exception IllegalStateException upon invocation of this method.     */    protected int engineDoFinal(byte[] in, int inOffset, int inLen,                                byte[] out, int outOffset)        throws IllegalBlockSizeException, ShortBufferException,               BadPaddingException {        throw new IllegalStateException("Cipher has not been initialized");    }     /**     * Returns the parameters used with this cipher which is always null     * for this cipher.     *     * @return null since this cipher does not use any parameters.     */    protected AlgorithmParameters engineGetParameters() {        return null;    }     /**     * Returns the key size of the given key object in number of bits.     *     * @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 (!AESCrypt.isKeySizeValid(encoded.length)) {            throw new InvalidKeyException("Invalid key length: " +                                          encoded.length + " bytes");        }        return encoded.length * 8;    }     /**     * 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 {        byte[] keyVal = key.getEncoded();        if ((keyVal == null) || (keyVal.length == 0)) {            throw new InvalidKeyException("Cannot get an encoding of " +                                          "the key to be wrapped");        }        byte[] out = new byte[keyVal.length + 8];         if (keyVal.length == 8) {            System.arraycopy(IV, 0, out, 0, IV.length);            System.arraycopy(keyVal, 0, out, IV.length, 8);            cipher.encryptBlock(out, 0, out, 0);        } else {            if (keyVal.length % 8 != 0) {                throw new IllegalBlockSizeException("length of the " +                    "to be wrapped key should be multiples of 8 bytes");            }            System.arraycopy(IV, 0, out, 0, IV.length);            System.arraycopy(keyVal, 0, out, IV.length, keyVal.length);            int N = keyVal.length/8;            byte[] buffer = new byte[blksize];            for (int j = 0; j < 6; j++) {                for (int i = 1; i <= N; i++) {                    int T = i + j*N;                    System.arraycopy(out, 0, buffer, 0, IV.length);                    System.arraycopy(out, i*8, buffer, IV.length, 8);                    cipher.encryptBlock(buffer, 0, buffer, 0);                    for (int k = 1; T != 0; k++) {                        byte v = (byte) T;                        buffer[IV.length - k] ^= v;                        T >>>= 8;                    }                    System.arraycopy(buffer, 0, out, 0, IV.length);                    System.arraycopy(buffer, 8, out, 8*i, 8);                }            }        }        return out;    }     /**     * 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 {        int wrappedKeyLen = wrappedKey.length;        // ensure the wrappedKey length is multiples of 8 bytes and non-zero        if (wrappedKeyLen == 0) {            throw new InvalidKeyException("The wrapped key is empty");        }        if (wrappedKeyLen % 8 != 0) {            throw new InvalidKeyException                ("The wrapped key has invalid key length");        }        byte[] out = new byte[wrappedKeyLen - 8];        byte[] buffer = new byte[blksize];        if (wrappedKeyLen == 16) {            cipher.decryptBlock(wrappedKey, 0, buffer, 0);            for (int i = 0; i < IV.length; i++) {                if (IV[i] != buffer[i]) {                    throw new InvalidKeyException("Integrity check failed");                }            }            System.arraycopy(buffer, IV.length, out, 0, out.length);        } else {            System.arraycopy(wrappedKey, 0, buffer, 0, IV.length);            System.arraycopy(wrappedKey, IV.length, out, 0, out.length);            int N = out.length/8;            for (int j = 5; j >= 0; j--) {                for (int i = N; i > 0; i--) {                    int T = i + j*N;                    System.arraycopy(out, 8*(i-1), buffer, IV.length, 8);                    for (int k = 1; T != 0; k++) {                        byte v = (byte) T;                        buffer[IV.length - k] ^= v;                        T >>>= 8;                    }                    cipher.decryptBlock(buffer, 0, buffer, 0);                    System.arraycopy(buffer, IV.length, out, 8*(i-1), 8);                }            }            for (int i = 0; i < IV.length; i++) {                if (IV[i] != buffer[i]) {                    throw new InvalidKeyException("Integrity check failed");                }            }        }        return ConstructKeys.constructKey(out, wrappedKeyAlgorithm,                                          wrappedKeyType);    }}