byte[] Sha512Algorithm(byte[] plaintext, UInt64[] H0, int numberBits)
{
Block1024[] blocks = ConvertPaddedMessageToBlock1024Array(PadPlainText1024(plaintext));
// Define the hash variable and set its initial values.
UInt64[] H = H0;
for (int i = 0; i < blocks.Length; i++)
{
UInt64[] W = CreateMessageScheduleSha512(blocks[i]);
// Set the working variables a,...,h to the current hash values.
UInt64 a = H[0];
UInt64 b = H[1];
UInt64 c = H[2];
UInt64 d = H[3];
UInt64 e = H[4];
UInt64 f = H[5];
UInt64 g = H[6];
UInt64 h = H[7];
for (int t = 0; t < 80; t++)
{
UInt64 T1 = h + Sigma1_512(e) + Ch(e, f, g) + this.K512[t] + W[t];
UInt64 T2 = Sigma0_512(a) + Maj(a, b, c);
h = g;
g = f;
f = e;
e = d + T1;
d = c;
c = b;
b = a;
a = T1 + T2;
}
// Update the current value of the hash H after processing block i.
H[0] += a;
H[1] += b;
H[2] += c;
H[3] += d;
H[4] += e;
H[5] += f;
H[6] += g;
H[7] += h;
}
// Concatenate all the Word64 Hash Values
byte[] hash = ShaUtilities.Word64ArrayToByteArray(H);
// The number of bytes in the final output hash
int numberBytes = numberBits / 8;
byte[] truncatedHash = new byte[numberBytes];
Array.Copy(hash, truncatedHash, numberBytes);
return(truncatedHash);
}
static Block1024[] ConvertPaddedMessageToBlock1024Array(byte[] M)
{
// We are assuming M is padded, so the number of bits in M is divisible by 1024
int numberBlocks = (M.Length * 8) / 1024; // same as: M.Length / 128
Block1024[] blocks = new Block1024[numberBlocks];
for (int i = 0; i < numberBlocks; i++)
{
// First extract the relavant subarray from M
byte[] B = new byte[128]; // 128 * 8 = 1024
for (int j = 0; j < 128; j++)
{
B[j] = M[i * 128 + j];
}
UInt64[] words = ShaUtilities.ByteArrayToWord64Array(B);
blocks[i] = new Block1024(words);
}
return(blocks);
}
