/*
* Copyright (c) 2004, 2012, 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
*/
abstract class AESWrapCipher extends CipherSpi {
public static final class General extends AESWrapCipher {
public General() {
super(-1);
}
}
public static final class AES128 extends AESWrapCipher {
public AES128() {
super(16);
}
}
public static final class AES192 extends AESWrapCipher {
public AES192() {
super(24);
}
}
public static final class AES256 extends AESWrapCipher {
public AES256() {
super(32);
}
}
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;
/*
* needed to support AES oids which associates a fixed key size
* to the cipher object.
*/
private final int fixedKeySize; // in bytes, -1 if no restriction
/**
* Creates an instance of AES KeyWrap cipher with default
* mode, i.e. "ECB" and padding scheme, i.e. "NoPadding".
*/
public AESWrapCipher(int keySize) {
cipher = new AESCrypt();
fixedKeySize = keySize;
}
/**
* 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");
}
AESCipher.checkKeySize(key, fixedKeySize);
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);
}
}