public static void AES_cbc_decrypt(AesCtx *ctx, byte *src, byte *dst, int size)
{
var blockBuffBytes = new byte[16];
var blockBuffPreviousBytes = new byte[16];
fixed(byte *blockBuff = blockBuffBytes)
fixed(byte *blockBuffPrevious = blockBuffPreviousBytes)
{
Memcpy(blockBuff, src, 16);
Memcpy(blockBuffPrevious, src, 16);
AES_decrypt(ctx, src, dst);
dst += 16;
src += 16;
int i;
for (i = 16; i < size; i += 16)
{
//step1: backup current block for next block decrypt
Memcpy(blockBuff, src, 16);
//step2: copy current block to destination
Memcpy(dst, src, 16);
//step3: decrypt current buffer in place
AES_decrypt(ctx, dst, dst);
//step4: XOR current buffer with previous buffer
xor_128(dst, blockBuffPrevious, dst);
//step5: swap buffers
Memcpy(blockBuffPrevious, blockBuff, 16);
dst += 16;
src += 16;
}
}
}
//No IV support!
public static void AES_cbc_encrypt(AesCtx *ctx, byte *src, byte *dst, int size)
{
var blockBuffBytes = new byte[16];
fixed(byte *blockBuff = blockBuffBytes)
{
int i;
for (i = 0; i < size; i += 16)
{
//step 1: copy block to dst
Memcpy(dst, src, 16);
//step 2: XOR with previous block
if (i != 0)
{
xor_128(dst, blockBuff, dst);
}
//step 3: encrypt the block -> it land in block buffer
AES_encrypt(ctx, dst, blockBuff);
//step 4: copy back the encrypted block to destination
Memcpy(dst, blockBuff, 16);
dst += 16;
src += 16;
}
}
}
public static void generate_subkey(AesCtx *ctx, byte *k1, byte *k2)
{
var lBytes = new byte[16];
var zBytes = new byte[16];
var tmpBytes = new byte[16];
fixed(byte *tmp = tmpBytes)
fixed(byte *l = lBytes)
fixed(byte *z = zBytes)
fixed(byte *constRb = ConstRb)
{
int i;
for (i = 0; i < 16; i++)
{
z[i] = 0;
}
AES_encrypt(ctx, z, l);
if ((l[0] & 0x80) == 0) /* If MSB(L) = 0, then K1 = L << 1 */
{
leftshift_onebit(l, k1);
}
else
{
/* Else K1 = ( L << 1 ) (+) Rb */
leftshift_onebit(l, tmp);
xor_128(tmp, constRb, k1);
}
if ((k1[0] & 0x80) == 0)
{
leftshift_onebit(k1, k2);
}
else
{
leftshift_onebit(k1, tmp);
xor_128(tmp, constRb, k2);
}
}
}
public static void AES_CMAC_forge(AesCtx *ctx, byte *input, int length, byte *forge)
{
var xBytes = new byte[16];
var yBytes = new byte[16];
var mLastBytes = new byte[16];
var paddedBytes = new byte[16];
var k1Bytes = new byte[16];
var k2Bytes = new byte[16];
fixed(byte *x = xBytes)
fixed(byte *y = yBytes)
fixed(byte *mLast = mLastBytes)
fixed(byte *padded = paddedBytes)
fixed(byte *k1 = k1Bytes)
fixed(byte *k2 = k2Bytes)
{
generate_subkey(ctx, k1, k2);
var n = (length + 15) / 16;
int flag;
if (n == 0)
{
n = 1;
flag = 0;
}
else
{
flag = (length % 16) == 0 ? 1 : 0;
}
if (flag != 0)
{
/* last block is complete block */
xor_128(&input[16 * (n - 1)], k1, mLast);
}
else
{
Padding(&input[16 * (n - 1)], padded, length % 16);
xor_128(padded, k2, mLast);
}
int i;
for (i = 0; i < 16; i++)
{
x[i] = 0;
}
for (i = 0; i < n - 1; i++)
{
xor_128(x, &input[16 * i], y); /* Y := Mi (+) X */
AES_encrypt(ctx, y, x); /* X := AES-128(KEY, Y); */
}
xor_128(x, mLast, y);
AES_decrypt(ctx, forge, x);
//printf("Pre-crypt value: "); for(i=0;i<0x10;i++) printf("%02x", X[i]); printf("\n");
xor_128(x, y, forge);
xor_128(forge, &input[16 * (n - 1)], y);
//AES_encrypt(Y, X, &aes);
//Update original input file so it produces the correct CMAC
for (i = 0; i < 16; i++)
{
input[(16 * (n - 1)) + i] = y[i];
}
}
}
public static void AES_CMAC(AesCtx *ctx, byte *input, int length, byte *mac)
{
var xBytes = new byte[16];
var yBytes = new byte[16];
var mLastBytes = new byte[16];
var paddedBytes = new byte[16];
var k1Bytes = new byte[16];
var k2Bytes = new byte[16];
fixed(byte *x = xBytes)
fixed(byte *y = yBytes)
fixed(byte *mLast = mLastBytes)
fixed(byte *padded = paddedBytes)
fixed(byte *k1 = k1Bytes)
fixed(byte *k2 = k2Bytes)
{
generate_subkey(ctx, k1, k2);
var n = (length + 15) / 16;
int flag;
if (n == 0)
{
n = 1;
flag = 0;
}
else
{
flag = (length % 16) == 0 ? 1 : 0;
}
if (flag != 0)
{
/* last block is complete block */
xor_128(&input[16 * (n - 1)], k1, mLast);
}
else
{
Padding(&input[16 * (n - 1)], padded, length % 16);
xor_128(padded, k2, mLast);
}
int i;
for (i = 0; i < 16; i++)
{
x[i] = 0;
}
for (i = 0; i < n - 1; i++)
{
xor_128(x, &input[16 * i], y); /* Y := Mi (+) X */
AES_encrypt(ctx, y, x); /* X := AES-128(KEY, Y); */
}
xor_128(x, mLast, y);
AES_encrypt(ctx, y, x);
for (i = 0; i < 16; i++)
{
mac[i] = x[i];
}
}
}
public static void AES_encrypt(AesCtx *ctx, byte *src, byte *dst)
{
RijndaelEncrypt(ctx->Ek, ctx->Nr, src, dst);
}
public static void AES_decrypt(AesCtx *ctx, byte *src, byte *dst)
{
RijndaelDecrypt(ctx->Dk, ctx->Nr, src, dst);
}
public static int AES_set_key(AesCtx *ctx, byte *key, int bits)
{
return(rijndael_set_key((RijndaelCtx *)ctx, key, bits));
}
