/**
* Method wrap
*
* @param in
* @param inOff
* @param inLen
* @return the wrapped bytes.
*/
public byte[] wrap(byte[] in, int inOff, int inLen) {
if (!forWrapping) {
throw new IllegalStateException("Not initialized for wrapping");
}
byte keyToBeWrapped[] = new byte[inLen];
System.arraycopy(in, inOff, keyToBeWrapped, 0, inLen);
// Compute the CMS Key Checksum, (section 5.6.1), call this CKS.
byte[] CKS = calculateCMSKeyChecksum(keyToBeWrapped);
// Let WKCKS = WK || CKS where || is concatenation.
byte[] WKCKS = new byte[keyToBeWrapped.length + CKS.length];
System.arraycopy(keyToBeWrapped, 0, WKCKS, 0, keyToBeWrapped.length);
System.arraycopy(CKS, 0, WKCKS, keyToBeWrapped.length, CKS.length);
// Encrypt WKCKS in CBC mode using KEK as the key and IV as the
// initialization vector. Call the results TEMP1.
int blockSize = engine.getBlockSize();
if (WKCKS.length % blockSize != 0) {
throw new IllegalStateException("Not multiple of block length");
}
engine.init(true, paramPlusIV);
byte TEMP1[] = new byte[WKCKS.length];
for (int currentBytePos = 0; currentBytePos != WKCKS.length; currentBytePos += blockSize) {
engine.processBlock(WKCKS, currentBytePos, TEMP1, currentBytePos);
}
// Let TEMP2 = IV || TEMP1.
byte[] TEMP2 = new byte[this.iv.length + TEMP1.length];
System.arraycopy(this.iv, 0, TEMP2, 0, this.iv.length);
System.arraycopy(TEMP1, 0, TEMP2, this.iv.length, TEMP1.length);
// Reverse the order of the octets in TEMP2 and call the result TEMP3.
byte[] TEMP3 = reverse(TEMP2);
// Encrypt TEMP3 in CBC mode using the KEK and an initialization vector
// of 0x 4a dd a2 2c 79 e8 21 05. The resulting cipher text is the desired
// result. It is 40 octets long if a 168 bit key is being wrapped.
ParametersWithIV param2 = new ParametersWithIV(this.param, IV2);
this.engine.init(true, param2);
for (int currentBytePos = 0; currentBytePos != TEMP3.length; currentBytePos += blockSize) {
engine.processBlock(TEMP3, currentBytePos, TEMP3, currentBytePos);
}
return TEMP3;
}
/**
* Method unwrap
*
* @param in
* @param inOff
* @param inLen
* @return the unwrapped bytes.
* @throws InvalidCipherTextException
*/
public byte[] unwrap(byte[] in, int inOff, int inLen) throws InvalidCipherTextException {
if (forWrapping) {
throw new IllegalStateException("Not set for unwrapping");
}
if (in == null) {
throw new InvalidCipherTextException("Null pointer as ciphertext");
}
final int blockSize = engine.getBlockSize();
if (inLen % blockSize != 0) {
throw new InvalidCipherTextException("Ciphertext not multiple of " + blockSize);
}
/*
// Check if the length of the cipher text is reasonable given the key
// type. It must be 40 bytes for a 168 bit key and either 32, 40, or
// 48 bytes for a 128, 192, or 256 bit key. If the length is not supported
// or inconsistent with the algorithm for which the key is intended,
// return error.
//
// we do not accept 168 bit keys. it has to be 192 bit.
int lengthA = (estimatedKeyLengthInBit / 8) + 16;
int lengthB = estimatedKeyLengthInBit % 8;
if ((lengthA != keyToBeUnwrapped.length) || (lengthB != 0)) {
throw new XMLSecurityException("empty");
}
*/
// Decrypt the cipher text with TRIPLedeS in CBC mode using the KEK
// and an initialization vector (IV) of 0x4adda22c79e82105. Call the output TEMP3.
ParametersWithIV param2 = new ParametersWithIV(this.param, IV2);
this.engine.init(false, param2);
byte TEMP3[] = new byte[inLen];
for (int currentBytePos = 0; currentBytePos != inLen; currentBytePos += blockSize) {
engine.processBlock(in, inOff + currentBytePos, TEMP3, currentBytePos);
}
// Reverse the order of the octets in TEMP3 and call the result TEMP2.
byte[] TEMP2 = reverse(TEMP3);
// Decompose TEMP2 into IV, the first 8 octets, and TEMP1, the remaining octets.
this.iv = new byte[8];
byte[] TEMP1 = new byte[TEMP2.length - 8];
System.arraycopy(TEMP2, 0, this.iv, 0, 8);
System.arraycopy(TEMP2, 8, TEMP1, 0, TEMP2.length - 8);
// Decrypt TEMP1 using TRIPLedeS in CBC mode using the KEK and the IV
// found in the previous step. Call the result WKCKS.
this.paramPlusIV = new ParametersWithIV(this.param, this.iv);
this.engine.init(false, this.paramPlusIV);
byte[] WKCKS = new byte[TEMP1.length];
for (int currentBytePos = 0; currentBytePos != WKCKS.length; currentBytePos += blockSize) {
engine.processBlock(TEMP1, currentBytePos, WKCKS, currentBytePos);
}
// Decompose WKCKS. CKS is the last 8 octets and WK, the wrapped key, are
// those octets before the CKS.
byte[] result = new byte[WKCKS.length - 8];
byte[] CKStoBeVerified = new byte[8];
System.arraycopy(WKCKS, 0, result, 0, WKCKS.length - 8);
System.arraycopy(WKCKS, WKCKS.length - 8, CKStoBeVerified, 0, 8);
// Calculate a CMS Key Checksum, (section 5.6.1), over the WK and compare
// with the CKS extracted in the above step. If they are not equal, return error.
if (!checkCMSKeyChecksum(result, CKStoBeVerified)) {
throw new InvalidCipherTextException("Checksum inside ciphertext is corrupted");
}
// WK is the wrapped key, now extracted for use in data decryption.
return result;
}
