throw new IllegalStateException("Not set for unwrapping");
}
if (in == null)
{
throw new InvalidCipherTextException("Null pointer as ciphertext");
}
if (inLen % engine.getBlockSize() != 0)
{
throw new InvalidCipherTextException("Ciphertext not multiple of "
+ engine.getBlockSize());
}
/*
* // 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];
System.arraycopy(in, inOff, TEMP3, 0, inLen);
for (int i = 0; i < (TEMP3.length / engine.getBlockSize()); i++)
{
int currentBytePos = i * engine.getBlockSize();
engine.processBlock(TEMP3, currentBytePos, TEMP3, currentBytePos);
}
// Reverse the order of the octets in TEMP3 and call the result TEMP2.
byte[] TEMP2 = new byte[TEMP3.length];
for (int i = 0; i < TEMP3.length; i++)
{
TEMP2[i] = TEMP3[TEMP3.length - (i + 1)];
}
// 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[] LCEKPADICV = new byte[TEMP1.length];
System.arraycopy(TEMP1, 0, LCEKPADICV, 0, TEMP1.length);
for (int i = 0; i < (LCEKPADICV.length / engine.getBlockSize()); i++)
{
int currentBytePos = i * engine.getBlockSize();
engine.processBlock(LCEKPADICV, currentBytePos, LCEKPADICV,
currentBytePos);
}
// Decompose LCEKPADICV. CKS is the last 8 octets and WK, the wrapped
// key, are
// those octets before the CKS.
byte[] result = new byte[LCEKPADICV.length - 8];
byte[] CKStoBeVerified = new byte[8];
System.arraycopy(LCEKPADICV, 0, result, 0, LCEKPADICV.length - 8);
System.arraycopy(LCEKPADICV, LCEKPADICV.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");
}
if ((result.length - ((result[0] & 0xff) + 1)) > 7)
{
throw new InvalidCipherTextException("too many pad bytes ("
+ (result.length - ((result[0] & 0xff) + 1)) + ")");
}
// CEK is the wrapped key, now extracted for use in data decryption.
byte[] CEK = new byte[result[0]];