com.sun.crypto.provider.AESKeyWrapPadded Maven / Gradle / Ivy
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
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* 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.
*
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package com.sun.crypto.provider;
import java.util.Arrays;
import java.security.*;
import java.security.spec.*;
import javax.crypto.*;
import javax.crypto.spec.*;
import static com.sun.crypto.provider.KWUtil.*;
/**
* This class implement the AES KeyWrap With Padding mode of operation as
* defined in
*
* "Recommendation for Block Cipher Modes of Operation: Methods for Key Wrapping"
* and represents AES cipher in KWP mode.
*/
class AESKeyWrapPadded extends FeedbackCipher {
// default integrity check value (icv) if iv is not supplied
static final byte[] ICV2 = { // SEMI_BLKSIZE/2 long
(byte) 0xA6, (byte) 0x59, (byte) 0x59, (byte) 0xA6,
};
private static final byte[] PAD_BLK = new byte[SEMI_BLKSIZE - 1];
// set the first semiblock of dest with iv and inLen
private static void setIvAndLen(byte[] dest, byte[] iv, int inLen) {
assert(dest.length >= SEMI_BLKSIZE) : "buffer needs at least 8 bytes";
System.arraycopy(iv, 0, dest, 0, iv.length);
dest[4] = (byte) ((inLen >>> 24) & 0xFF);
dest[5] = (byte) ((inLen >>> 16) & 0xFF);
dest[6] = (byte) ((inLen >>> 8) & 0xFF);
dest[7] = (byte) (inLen & 0xFF);
}
// validate the recovered internal ivAndLen semiblock against iv and
// return the recovered input length
private static int validateIV(byte[] ivAndLen, byte[] iv)
throws IllegalBlockSizeException {
// check against iv and fail if not match
int match = 0;
for (int i = 0; i < ICV2.length; i++) {
match |= (ivAndLen[i] ^ iv[i]);
}
if (match != 0) {
throw new IllegalBlockSizeException("Integrity check failed");
}
int outLen = ivAndLen[4];
for (int k = 5; k < SEMI_BLKSIZE; k++) {
if (outLen != 0) {
outLen <<= 8;
}
outLen |= ivAndLen[k] & 0xFF;
}
return outLen;
}
AESKeyWrapPadded() {
super(new AESCrypt());
}
/**
* Gets the name of this feedback mode.
*
* @return the string KW
*/
@Override
String getFeedback() {
return "KWP";
}
/**
* Save the current content of this cipher.
*/
@Override
void save() {
throw new UnsupportedOperationException("save not supported");
};
/**
* Restores the content of this cipher to the previous saved one.
*/
@Override
void restore() {
throw new UnsupportedOperationException("restore not supported");
};
/**
* Initializes the cipher in the specified mode with the given key
* and iv.
*
* @param decrypting flag indicating encryption or decryption
* @param algorithm the algorithm name
* @param key the key
* @param iv the iv
*
* @exception InvalidKeyException if the given key is inappropriate for
* initializing this cipher
* @exception InvalidAlgorithmParameterException if the given iv is
* non-null and not the right length
*/
@Override
void init(boolean decrypting, String algorithm, byte[] key, byte[] iv)
throws InvalidKeyException, InvalidAlgorithmParameterException {
if (key == null) {
throw new InvalidKeyException("Invalid null key");
}
if (iv != null && iv.length != ICV2.length) {
throw new InvalidAlgorithmParameterException("Invalid IV length");
}
embeddedCipher.init(decrypting, algorithm, key);
// iv is retrieved from IvParameterSpec.getIV() which is already cloned
this.iv = (iv == null? ICV2 : iv);
}
/**
* Resets the iv to its original value.
* This is used when doFinal is called in the Cipher class, so that the
* cipher can be reused (with its original iv).
*/
@Override
void reset() {
throw new UnsupportedOperationException("reset not supported");
};
// no support for multi-part encryption
@Override
int encrypt(byte[] pt, int ptOfs, int ptLen, byte[] ct, int ctOfs) {
throw new UnsupportedOperationException("multi-part not supported");
};
// no support for multi-part decryption
@Override
int decrypt(byte[] ct, int ctOfs, int ctLen, byte[] pt, int ptOfs) {
throw new UnsupportedOperationException("multi-part not supported");
};
/**
* Performs single-part encryption operation.
*
* The input pt, starting at 0
* and ending at ptLen-1, is encrypted.
* The result is stored in place into pt, starting at
* 0.
*
*
The subclass that implements Cipher should ensure that
* init has been called before this method is called.
*
* @param pt the input buffer with the data to be encrypted
* @param dummy1 the offset in pt which is always 0
* @param ptLen the length of the input data
* @param dummy2 the output buffer for the encryption which is always pt
* @param dummy3 the offset in the output buffer which is always 0
* @return the number of bytes placed into pt
*/
@Override
int encryptFinal(byte[] pt, int dummy1, int ptLen, byte[] dummy2,
int dummy3) throws IllegalBlockSizeException {
int actualLen = ptLen - SEMI_BLKSIZE;
if (actualLen < 1) {
throw new IllegalBlockSizeException
("data should have at least 1 byte");
}
if (ptLen % SEMI_BLKSIZE != 0) {
int rem = SEMI_BLKSIZE - (ptLen % SEMI_BLKSIZE);
System.arraycopy(PAD_BLK, 0, pt, ptLen, rem);
ptLen += rem;
}
if (ptLen <= BLKSIZE) {
// overwrite the first semiblock with iv and input length
setIvAndLen(pt, iv, actualLen);
embeddedCipher.encryptBlock(pt, 0, pt, 0);
} else {
byte[] ivAndLen = new byte[SEMI_BLKSIZE];
setIvAndLen(ivAndLen, iv, actualLen);
ptLen = W(ivAndLen, pt, ptLen, embeddedCipher);
}
return ptLen;
}
/**
* Performs single-part decryption operation.
*
*
The input ct, starting at 0
* and ending at ctLen-1, is decrypted.
* The result is stored in place into ct, starting at
* 0.
*
*
The subclass that implements Cipher should ensure that
* init has been called before this method is called.
*
* @param ct the input buffer with the data to be decrypted
* @param dummy1 the offset in ct which is always 0
* @param ctLen the length of the input data
* @param dummy2 the output buffer for the decryption which is always ct
* @param dummy3 the offset in the output buffer which is always 0
* @return the number of bytes placed into ct
*/
@Override
int decryptFinal(byte[] ct, int dummy1, int ctLen, byte[] dummy2,
int dummy3) throws IllegalBlockSizeException {
if (ctLen < BLKSIZE || ctLen % SEMI_BLKSIZE != 0) {
throw new IllegalBlockSizeException
("data should be at least 16 bytes and multiples of 8");
}
byte[] ivAndLen = new byte[SEMI_BLKSIZE];
if (ctLen == BLKSIZE) {
embeddedCipher.decryptBlock(ct, 0, ct, 0);
System.arraycopy(ct, 0, ivAndLen, 0, SEMI_BLKSIZE);
System.arraycopy(ct, SEMI_BLKSIZE, ct, 0, SEMI_BLKSIZE);
ctLen -= SEMI_BLKSIZE;
} else {
ctLen = W_INV(ct, ctLen, ivAndLen, embeddedCipher);
}
int outLen = validateIV(ivAndLen, this.iv);
// check padding bytes
int padLen = ctLen - outLen;
if (padLen < 0 || padLen >= SEMI_BLKSIZE) {
throw new IllegalBlockSizeException("Invalid KWP pad length " +
padLen);
}
for (int k = padLen; k > 0; k--) {
if (ct[ctLen - k] != 0) {
throw new IllegalBlockSizeException("Invalid KWP pad value");
}
}
return outLen;
}
}