void FillBlock(const block* prev_block, const block* ref_block, block* next_block, const uint64_t* Sbox) {
block blockR;
CopyBlock(&blockR,ref_block);
XORBlock(&blockR,prev_block);
block block_tmp;
CopyBlock(&block_tmp, &blockR);
uint64_t x = 0;
if (Sbox != NULL) {
x = blockR.v[0] ^ blockR.v[ARGON2_WORDS_IN_BLOCK - 1];
for (int i = 0; i < 6 * 16; ++i) {
uint32_t x1 = x >> 32;
uint32_t x2 = x & 0xFFFFFFFF;
uint64_t y = Sbox[x1 & ARGON2_SBOX_MASK];
uint64_t z = Sbox[(x2 & ARGON2_SBOX_MASK) + ARGON2_SBOX_SIZE / 2];
x = (uint64_t) x1 * (uint64_t) x2;
x += y;
x ^= z;
}
}
// =========================================================================
// Decryption function
// Note: PlaintextLength must be set to the size of the PlaintextData buffer on
// entry; on exit, this will be set to the size of the buffer used.
NTSTATUS
ImpCypherDecryptSectorData(
IN GUID* CypherGUID,
IN LARGE_INTEGER SectorID, // Indexed from zero
IN int SectorSize, // In bytes
IN int KeyLength, // In bits
IN FREEOTFEBYTE* Key,
IN char* KeyASCII, // ASCII representation of "Key"
IN int IVLength, // In bits
IN FREEOTFEBYTE* IV,
IN int CyphertextLength, // In bytes
IN FREEOTFEBYTE* CyphertextData,
OUT FREEOTFEBYTE* PlaintextData
)
{
NTSTATUS status = STATUS_SUCCESS;
// Null IV in case we're not given an IV
char zeroIV[FREEOTFE_MAX_CYPHER_BLOCKSIZE];
int i;
INTEGER_128 blockID128;
int errnum;
TWOFISH(CONTEXT) context;
DEBUGOUTCYPHERIMPL(DEBUGLEV_ENTER, (TEXT("ImpCypherDecryptData\n")));
if (
(IsEqualGUID(&CIPHER_GUID_TWOFISH_256_XTS, CypherGUID)) ||
(IsEqualGUID(&CIPHER_GUID_TWOFISH_192_XTS, CypherGUID)) ||
(IsEqualGUID(&CIPHER_GUID_TWOFISH_128_XTS, CypherGUID))
)
{
// Generate index in correct format
// XTS uses:
// *) The sector index (i.e. the number of N-bit sectors)
// *) The first sector is sector 0
// *) Littleendian format
LARGE_INTEGER__To__INTEGER_128_LittleEndian(
SectorID,
blockID128
);
if ((errnum = xts_decrypt(
&context,
&(TWOFISH(set_key)),
&(TWOFISH(encrypt)),
&(TWOFISH(decrypt)),
((KeyLength/2)),
Key,
((KeyLength/2)),
&(Key[(KeyLength/2)/8]),
CyphertextData,
CyphertextLength,
PlaintextData,
blockID128
)) != CRYPT_OK)
{
DEBUGOUTCYPHERIMPL(DEBUGLEV_ERROR, (TEXT("Unable to decrypt block (errnum: %d)\n"), errnum));
status = STATUS_UNSUCCESSFUL;
}
}
else if (
(IsEqualGUID(&CIPHER_GUID_TWOFISH_256_CBC, CypherGUID)) ||
(IsEqualGUID(&CIPHER_GUID_TWOFISH_192_CBC, CypherGUID)) ||
(IsEqualGUID(&CIPHER_GUID_TWOFISH_128_CBC, CypherGUID))
)
{
// Handle situation where a NULL/zero length IV is passed in
if ( (IVLength == 0) || (IV == NULL) )
{
FREEOTFE_MEMZERO(&zeroIV, sizeof(zeroIV));
IV = (char*)&zeroIV;
}
// Process data using CBC mode
//
// CBC Mode DECRYPT:
// *) Setup key
// *) For each block...
// *) Decrypt cyphertext with key
// *) XOR output plaintext with IV
// *) IV = Cyphertext data
// Note: "dec" specified; we're DECRYPTING
TWOFISH(set_key)(&context, Key, KeyLength, dec);
for (i=0; i < CyphertextLength; i += (TWOFISH_BLOCK_SIZE / 8))
{
TWOFISH(decrypt)(&context, CyphertextData+i, PlaintextData+i);
XORBlock(PlaintextData+i, IV, PlaintextData+i, (TWOFISH_BLOCK_SIZE / 8));
IV = CyphertextData+i;
}
}
else
{
DEBUGOUTCYPHERIMPL(DEBUGLEV_ERROR, (TEXT("Unsupported cipher GUID passed in.\n")));
status = STATUS_INVALID_PARAMETER;
}
SecZeroMemory(&context, sizeof(context));
DEBUGOUTCYPHERIMPL(DEBUGLEV_EXIT, (TEXT("ImpCypherDecryptData\n")));
return status;
}
// =========================================================================
// Decryption function
// Note: PlaintextLength must be set to the size of the PlaintextData buffer on
// entry; on exit, this will be set to the size of the buffer used.
NTSTATUS
ImpCypherDecryptSectorData(
IN GUID* CypherGUID,
IN LARGE_INTEGER SectorID, // Indexed from zero
IN int SectorSize, // In bytes
IN int KeyLength, // In bits
IN FREEOTFEBYTE* Key,
IN char* KeyASCII, // ASCII representation of "Key"
IN int IVLength, // In bits
IN FREEOTFEBYTE* IV,
IN int CyphertextLength, // In bytes
IN FREEOTFEBYTE* CyphertextData,
OUT FREEOTFEBYTE* PlaintextData
)
{
NTSTATUS status = STATUS_SUCCESS;
// Null IV in case we're not given an IV
char zeroIV[FREEOTFE_MAX_CYPHER_BLOCKSIZE];
int i;
CONTEXT context;
DEBUGOUTCYPHERIMPL(DEBUGLEV_ENTER, (TEXT("ImpCypherDecryptData\n")));
if (
(IsEqualGUID(&CIPHER_GUID_CAST6_256_CBC, CypherGUID)) ||
(IsEqualGUID(&CIPHER_GUID_CAST6_224_CBC, CypherGUID)) ||
(IsEqualGUID(&CIPHER_GUID_CAST6_192_CBC, CypherGUID)) ||
(IsEqualGUID(&CIPHER_GUID_CAST6_160_CBC, CypherGUID)) ||
(IsEqualGUID(&CIPHER_GUID_CAST6_128_CBC, CypherGUID))
)
{
// Handle situation where a NULL/zero length IV is passed in
if ( (IVLength == 0) || (IV == NULL) )
{
FREEOTFE_MEMZERO(&zeroIV, sizeof(zeroIV));
IV = (char*)&zeroIV;
}
// Process data using CBC mode
//
// CBC Mode DECRYPT:
// *) Setup key
// *) For each block...
// *) Decrypt cyphertext with key
// *) XOR output plaintext with IV
// *) IV = Cyphertext data
// Note: "dec" specified; we're DECRYPTING
set_key(&context, (u4byte *)Key, KeyLength);
for (i=0; i < CyphertextLength; i += (CAST6_BLOCK_SIZE / 8))
{
decrypt(&context, (u4byte *)(CyphertextData+i), (u4byte *)(PlaintextData+i));
XORBlock(PlaintextData+i, IV, PlaintextData+i, (CAST6_BLOCK_SIZE / 8));
IV = CyphertextData+i;
}
}
else
{
DEBUGOUTCYPHERIMPL(DEBUGLEV_ERROR, (TEXT("Unsupported cipher GUID passed in.\n")));
status = STATUS_INVALID_PARAMETER;
}
SecZeroMemory(&context, sizeof(context));
DEBUGOUTCYPHERIMPL(DEBUGLEV_EXIT, (TEXT("ImpCypherDecryptData\n")));
return status;
}
