static byte[] Sha512Algorithm(byte[] plaintext, Word64[] H0, int numberBits)
{
Block1024[] blocks = ConvertPaddedMessageToBlock1024Array(PadPlainText1024(plaintext));
// Define the hash variable and set its initial values.
Word64[] H = H0;
for (int i = 0; i < blocks.Length; i++)
{
Word64[] W = CreateMessageScheduleSha512(blocks[i]);
// Set the working variables a,...,h to the current hash values.
Word64 a = H[0];
Word64 b = H[1];
Word64 c = H[2];
Word64 d = H[3];
Word64 e = H[4];
Word64 f = H[5];
Word64 g = H[6];
Word64 h = H[7];
for (int t = 0; t < 80; t++)
{
Word64 T1 = h + Sigma1_512(e) + Ch(e, f, g) + K512[t] + W[t];
Word64 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);
}
public byte[] Compute(byte[] message, int numberBits = 512)
{
DefineH0Sha512();
DefineK512();
byte[] paddedMessage = PadMessage1024(message);
Block1024[] blocks = ConvertPaddedMessageToBlock1024Array(paddedMessage);
Word64[] H = H0Sha512;
for (int i = 0; i < blocks.Length; i++)
{
Word64[] W = CreateMessageScheduleSha512(blocks[i]);
Word64 a = H[0];
Word64 b = H[1];
Word64 c = H[2];
Word64 d = H[3];
Word64 e = H[4];
Word64 f = H[5];
Word64 g = H[6];
Word64 h = H[7];
for (int t = 0; t < 80; t++)
{
Word64 T1 = h + Sigma1_512(e) + Ch(e, f, g) + K512[t] + W[t];
Word64 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;
}
H[0] += a;
H[1] += b;
H[2] += c;
H[3] += d;
H[4] += e;
H[5] += f;
H[6] += g;
H[7] += h;
}
byte[] hash = ShaUtil.Word64ArrayToByteArray(H);
int numberBytes = numberBits / 8;
byte[] truncatedHash = new byte[numberBytes];
Array.Copy(hash, truncatedHash, numberBytes);
return(truncatedHash);
}
public static Word64 ByteArrayToWord64(byte[] B, int startIndex)
{
// We assume: 0 <= startIndex < B. Length, and startIndex + 8 <= B.Length
Word64 c = 256;
Word64 output = 0;
for (int i = startIndex; i < startIndex + 8; i++)
{
output = output * c + B[i];
}
return(output);
}
public static Word64[] ByteArrayToWord64Array(byte[] B)
{
// We assume B is not null, is not empty and number elements is divisible by 8
int numberWords = B.Length / 8; // 8 bytes for each Word32
Word64[] wordArray = new Word64[numberWords];
for (int i = 0; i < numberWords; i++)
{
wordArray[i] = ByteArrayToWord64(B, 8 * i);
}
return(wordArray);
}
static Word64[] CreateMessageScheduleSha512(Block1024 block)
{
Word64[] W = new Word64[80];
for (int t = 0; t < 80; t++)
{
if (t < 16)
{
W[t] = block.words[t];
}
else
{
W[t] = sigma1_512(W[t - 2]) + W[t - 7] + sigma0_512(W[t - 15]) + W[t - 16];
}
}
return(W);
}
static Word64[] CreateMessageScheduleSha512(Block1024 block)
{
// The message schedule.
Word64[] W = new Word64[80];
// Prepare the message schedule W.
// The first 16 words in W are the same as the words of the block.
// The remaining 80-16 =64 words in W are functions of the previously defined words.
for (int t = 0; t < 80; t++)
{
if (t < 16)
{
W[t] = block.words[t];
}
else
{
W[t] = sigma1_512(W[t - 2]) + W[t - 7] + sigma0_512(W[t - 15]) + W[t - 16];
}
}
return(W);
}
static Word64 Sigma0_512(Word64 x)
{
return(RotR(28, x) ^ RotR(34, x) ^ RotR(39, x));
}
static Word64 Maj(Word64 x, Word64 y, Word64 z)
{
return((x & y) ^ (x & z) ^ (y & z));
}
static Word64 Ch(Word64 x, Word64 y, Word64 z)
{
return((x & y) ^ (~x & z));
}
public static byte[] Word64ToByteArray(Word64 x)
{
byte[] b = BitConverter.GetBytes(x);
Array.Reverse(b);
return(b);
}
static Word64 ShR(int n, Word64 x)
{
// should have 0 <= n < 64
return(x >> n);
}
static Word64 RotR(int n, Word64 x)
{
// should have 0 <= n < 64
return((x >> n) | (x << 64 - n));
}
static Word64 Sigma1_512(Word64 x)
{
return(RotR(14, x) ^ RotR(18, x) ^ RotR(41, x));
}
static Word64 sigma1_512(Word64 x)
{
return(RotR(19, x) ^ RotR(61, x) ^ ShR(6, x));
}
static Word64 sigma0_512(Word64 x)
{
return(RotR(1, x) ^ RotR(8, x) ^ ShR(7, x));
}
public static string Word64ToHexString(Word64 x)
{
return(ByteArrayToHexString(Word64ToByteArray(x)));
}
