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KeccakHash minor opt #10

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KeccakHash minor opt #10

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b2c690a
KeccakHash minor opt
tkstanczak Nov 23, 2018
852aec7
fixed an obvious mistake
tkstanczak Nov 23, 2018
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75 changes: 28 additions & 47 deletions src/Meadow.Core/Cryptography/KeccakHash.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -15,6 +15,8 @@ public class KeccakHash
#region Constants
public const int HASH_SIZE = 32;
private const int STATE_SIZE = 200;
private const int ROUND_SIZE = STATE_SIZE - 2 * HASH_SIZE;
private const int ROUND_SIZE_U64 = ROUND_SIZE / 8;
private const int HASH_DATA_AREA = 136;
private const int ROUNDS = 24;
private const int LANE_BITS = 8 * 8;
Expand Down Expand Up @@ -430,70 +432,49 @@ public static byte[] ComputeHashBytes(Span<byte> input, int size = HASH_SIZE)
return output;
}

static readonly ArrayPool<byte> _arrayPool = ArrayPool<byte>.Shared;


// compute a keccak hash (md) of given byte length from "in"
public static void ComputeHash(Span<byte> input, Span<byte> output)
{
if (output.Length <= 0 || output.Length > STATE_SIZE)
{
throw new ArgumentException("Bad keccak use");
}

Span<ulong> state = stackalloc ulong[STATE_SIZE / sizeof(ulong)];
Span<byte> temp = stackalloc byte[TEMP_BUFF_SIZE];

byte[] stateArray = _arrayPool.Rent(STATE_SIZE);
byte[] tempArray = _arrayPool.Rent(TEMP_BUFF_SIZE);

try
var remainingInputLength = input.Length;
int i;
for (; remainingInputLength >= ROUND_SIZE; remainingInputLength -= ROUND_SIZE, input = input.Slice(ROUND_SIZE))
{
Span<ulong> state = MemoryMarshal.Cast<byte, ulong>(stateArray.AsSpan(0, STATE_SIZE));
Span<byte> temp = tempArray.AsSpan(0, TEMP_BUFF_SIZE);

state.Clear();
temp.Clear();

int roundSize = STATE_SIZE == output.Length ? HASH_DATA_AREA : STATE_SIZE - (2 * output.Length);
int roundSizeU64 = roundSize / 8;

var inputLength = input.Length;
int i;
for (; inputLength >= roundSize; inputLength -= roundSize, input = input.Slice(roundSize))
var input64 = MemoryMarshal.Cast<byte, ulong>(input);

for (i = 0; i < ROUND_SIZE_U64; i++)
{
var input64 = MemoryMarshal.Cast<byte, ulong>(input);

for (i = 0; i < roundSizeU64; i++)
{
state[i] ^= input64[i];
}

KeccakF(state, ROUNDS);
state[i] ^= input64[i];
}

// last block and padding
if (inputLength >= TEMP_BUFF_SIZE || inputLength > roundSize || roundSize - inputLength + inputLength + 1 >= TEMP_BUFF_SIZE || roundSize == 0 || roundSize - 1 >= TEMP_BUFF_SIZE || roundSizeU64 * 8 > TEMP_BUFF_SIZE)
{
throw new ArgumentException("Bad keccak use");
}
KeccakF(state);
}

input.Slice(0, inputLength).CopyTo(temp);
temp[inputLength++] = 1;
temp[roundSize - 1] |= 0x80;
// last block and padding
if (input.Length >= TEMP_BUFF_SIZE || input.Length > ROUND_SIZE || ROUND_SIZE + 1 >= TEMP_BUFF_SIZE || ROUND_SIZE == 0 || ROUND_SIZE - 1 >= TEMP_BUFF_SIZE || ROUND_SIZE_U64 * 8 > TEMP_BUFF_SIZE)
{
throw new ArgumentException("Bad keccak use");
}

var tempU64 = MemoryMarshal.Cast<byte, ulong>(temp);
input.Slice(0, remainingInputLength).CopyTo(temp);
temp[remainingInputLength] = 1;
temp[ROUND_SIZE - 1] |= 0x80;

for (i = 0; i < roundSizeU64; i++)
{
state[i] ^= tempU64[i];
}
var tempU64 = MemoryMarshal.Cast<byte, ulong>(temp);

KeccakF(state, ROUNDS);
MemoryMarshal.AsBytes(state).Slice(0, output.Length).CopyTo(output);
}
finally
for (i = 0; i < ROUND_SIZE_U64; i++)
{
_arrayPool.Return(stateArray);
_arrayPool.Return(tempArray);
state[i] ^= tempU64[i];
}

KeccakF(state, ROUNDS);
MemoryMarshal.AsBytes(state.Slice(0, HASH_SIZE / sizeof(ulong))).CopyTo(output);
}

public static void Keccak1600(Span<byte> input, Span<byte> output)
Expand Down