public override byte [] DecryptValue(byte [] keyWrap)
{
int N = keyWrap.Length / 8 - 1;
int rem = keyWrap.Length % 8;
if (rem != 0)
{
throw new Exception("key must be in blocks of 8");
}
byte [] key = new byte[N * 8];
AesNoPadding anp = new AesNoPadding(_tdcsp);
if (N == 1) //If N is 1:
{
byte [] B = anp.Decrypt(keyWrap);
for (int msb = 0; msb < 8; msb++) //If MSB(B) is 0xA6A6A6A6A6A6A6A6
{
if (B[msb] != kwIv[msb])
{
throw new Exception("unwrapped key is bad size1");
}
}
Buffer.BlockCopy(B, 8, key, 0, 8); //P(1)=LSB(B)
return(key);
}
Buffer.BlockCopy(keyWrap, 8, key, 0, key.Length); //For i=1 to N, R(i)=C(i)
byte [] A = new byte[8];
byte [] R = new byte[8];
Buffer.BlockCopy(keyWrap, 0, A, 0, 8); //A=C(0)
for (int j = 5; j >= 0; j--) //For j=5 to 0,
{
for (int i = N; i >= 1; i--) //For i=N to 1,
{
long t = (long)i + (j * N); //t= i + j*N
for (int k = 0; k < 8; k++)
{
byte x = ((byte)((t >> ((8 * (7 - k)) & 63)) & ((long)255))); //WTF?
A[k] = (byte)(A[k] ^ x);
}
//B=AES(K)dec(XOR(t,A)|R(i))
Buffer.BlockCopy(key, (i - 1) * 8, R, 0, 8);
byte [] A_R = ConcatBa(A, R);
byte [] B = anp.Decrypt(A_R);
Buffer.BlockCopy(B, 0, A, 0, 8); //A=MSB(B)
Buffer.BlockCopy(B, 8, key, (i - 1) * 8, 8); //R(i)=LSB(B)
}
}
for (int a = 0; a < 8; a++)
{
if (A[a] != kwIv[a]) //If A is 0xA6A6A6A6A6A6A6A6
{
throw new Exception("unwrapped key is bad size2");
}
}
return(key); //For i=1 to N, P(i)=R(i)
}
public override byte [] EncryptValue(byte [] key)
{
int N = key.Length / 8;
int rem = key.Length % 8;
if (rem != 0)
{
throw new Exception("key must be in blocks of 8");
}
AesNoPadding anp = new AesNoPadding(_tdcsp);
if (N == 1) //If N is 1
{
//B=AES(K)enc(0xA6A6A6A6A6A6A6A6|P(1))
byte [] keyIv_key = ConcatBa(kwIv, key);
byte [] B = anp.Encrypt(keyIv_key);
return(B);
}
//For i=1 to N, R(i)=P(i)
byte [] retBa = new byte[(N + 1) * 8];
Buffer.BlockCopy(key, 0, retBa, 8, key.Length);
byte [] A = (byte [])kwIv.Clone(); //Set A to 0xA6A6A6A6A6A6A6A6
byte [] R = new byte[8];
for (int j = 0; j <= 5; j++) //Forj=0 to 5,
{
for (int i = 1; i <= N; i++) //For i=1 to N,
{
long t = (long)i + (j * N); //t= i + j*N
Buffer.BlockCopy(retBa, i * 8, R, 0, 8);
byte [] A_R = ConcatBa(A, R);
byte [] B = anp.Encrypt(A_R); //B=AES(K)enc(A|R(i))
for (int k = 0; k < 8; k++)
{
int xt = ((byte)((t >> ((8 * (7 - k)) & 63)) & ((long)255))); //WTF?
A[k] = (byte)(xt ^ B[k]); //A=XOR(t,MSB(B))
}
Buffer.BlockCopy(B, 8, retBa, i * 8, 8); //R(i)=LSB(B)
}
}
Buffer.BlockCopy(A, 0, retBa, 0, 8); //Set C(0)=A
return(retBa); //For i=1 to N, C(i)=R(i)
}
