sha3

/*
The Keccak sponge function, designed by Guido Bertoni, Joan Daemen,
Michaël Peeters and Gilles Van Assche. For more information, feedback or
questions, please refer to our website: http://keccak.noekeon.org/

Implementation by the designers,
hereby denoted as "the implementer".

To the extent possible under law, the implementer has waived all copyright
and related or neighboring rights to the source code in this file.
http://creativecommons.org/publicdomain/zero/1.0/
*/

#include <string.h>
#include "../brg_endian.h"
#include "../KeccakNISTInterface.h"
#include "../KeccakF-1600-interface.h"

typedef unsigned char UINT8;
typedef unsigned long long int UINT64;

#define nrRounds 24
UINT64 KeccakRoundConstants[nrRounds];
#define nrLanes 25
unsigned int KeccakRhoOffsets[nrLanes];

void KeccakPermutationOnWords(UINT64 *state);
void keccak_theta(UINT64 *A);
void keccak_rho(UINT64 *A);
void keccak_pi(UINT64 *A);
void keccak_chi(UINT64 *A);
void keccak_iota(UINT64 *A, unsigned int indexRound);

void fromBytesToWords(UINT64 *stateAsWords, const unsigned char *state)
{
    unsigned int i, j;

    for(i=0; i<(KeccakPermutationSize/64); i++) {
        stateAsWords[i] = 0;
        for(j=0; j<(64/8); j++)
            stateAsWords[i] |= (UINT64)(state[i*(64/8)+j]) << (8*j);
    }
}

void fromWordsToBytes(unsigned char *state, const UINT64 *stateAsWords)
{
    unsigned int i, j;

    for(i=0; i<(KeccakPermutationSize/64); i++)
        for(j=0; j<(64/8); j++)
            state[i*(64/8)+j] = (stateAsWords[i] >> (8*j)) & 0xFF;
}

void KeccakPermutation(unsigned char *state)
{
#if (PLATFORM_BYTE_ORDER != IS_LITTLE_ENDIAN)
    UINT64 stateAsWords[KeccakPermutationSize/64];
#endif

#if (PLATFORM_BYTE_ORDER == IS_LITTLE_ENDIAN)
    KeccakPermutationOnWords((UINT64*)state);
#else
    fromBytesToWords(stateAsWords, state);
    KeccakPermutationOnWords(stateAsWords);
    fromWordsToBytes(state, stateAsWords);
#endif
}

void KeccakPermutationAfterXor(unsigned char *state, const unsigned char *data, unsigned int dataLengthInBytes)
{
    unsigned int i;

    for(i=0; i<dataLengthInBytes; i++)
        state[i] ^= data[i];
    KeccakPermutation(state);
}

void KeccakPermutationOnWords(UINT64 *state)
{
    unsigned int i;

    for(i=0; i<nrRounds; i++) {
        keccak_theta(state);
        keccak_rho(state);
        keccak_pi(state);
        keccak_chi(state);
        keccak_iota(state, i);
    }
}

#define index(x, y) (((x)%5)+5*((y)%5))
#define ROL64(a, offset) ((offset != 0) ? ((((UINT64)a) << offset) ^ (((UINT64)a) >> (64-offset))) : a)

void keccak_theta(UINT64 *A)
{
    unsigned int x, y;
    UINT64 C[5], D[5];

    for(x=0; x<5; x++) {
        C[x] = 0; 
        for(y=0; y<5; y++) 
            C[x] ^= A[index(x, y)];
    }
    for(x=0; x<5; x++)
        D[x] = ROL64(C[(x+1)%5], 1) ^ C[(x+4)%5];
    for(x=0; x<5; x++)
        for(y=0; y<5; y++)
            A[index(x, y)] ^= D[x];
}

void keccak_rho(UINT64 *A)
{
    unsigned int x, y;

    for(x=0; x<5; x++) for(y=0; y<5; y++)
        A[index(x, y)] = ROL64(A[index(x, y)], KeccakRhoOffsets[index(x, y)]);
}

void keccak_pi(UINT64 *A)
{
    unsigned int x, y;
    UINT64 tempA[25];

    for(x=0; x<5; x++)
        for(y=0; y<5; y++)
            tempA[index(x, y)] = A[index(x, y)];
    for(x=0; x<5; x++)
        for(y=0; y<5; y++)
            A[index(0*x+1*y, 2*x+3*y)] = tempA[index(x, y)];
}

void keccak_chi(UINT64 *A)
{
    unsigned int x, y;
    UINT64 C[5];

    for(y=0; y<5; y++) { 
        for(x=0; x<5; x++)
            C[x] = A[index(x, y)] ^ ((~A[index(x+1, y)]) & A[index(x+2, y)]);
        for(x=0; x<5; x++)
            A[index(x, y)] = C[x];
    }
}

void keccak_iota(UINT64 *A, unsigned int indexRound)
{
    A[index(0, 0)] ^= KeccakRoundConstants[indexRound];
}

int LFSR86540(UINT8 *LFSR)
{
    int result = ((*LFSR) & 0x01) != 0;
    if (((*LFSR) & 0x80) != 0)
        // Primitive polynomial over GF(2): x^8+x^6+x^5+x^4+1
        (*LFSR) = ((*LFSR) << 1) ^ 0x71;
    else
        (*LFSR) <<= 1;
    return result;
}

void KeccakInitializeRoundConstants()
{
    UINT8 LFSRstate = 0x01;
    unsigned int i, j, bitPosition;

    for(i=0; i<nrRounds; i++) {
        KeccakRoundConstants[i] = 0;
        for(j=0; j<7; j++) {
            bitPosition = (1<<j)-1; //2^j-1
            if (LFSR86540(&LFSRstate))
                KeccakRoundConstants[i] ^= (UINT64)1<<bitPosition;
        }
    }
}

void KeccakInitializeRhoOffsets()
{
    unsigned int x, y, t, newX, newY;

    KeccakRhoOffsets[index(0, 0)] = 0;
    x = 1;
    y = 0;
    for(t=0; t<24; t++) {
        KeccakRhoOffsets[index(x, y)] = ((t+1)*(t+2)/2) % 64;
        newX = (0*x+1*y) % 5;
        newY = (2*x+3*y) % 5;
        x = newX;
        y = newY;
    }
}

void KeccakInitialize()
{
    KeccakInitializeRoundConstants();
    KeccakInitializeRhoOffsets();
}

void KeccakInitializeState(unsigned char *state)
{
    memset(state, 0, KeccakPermutationSizeInBytes);
}

#ifdef ProvideFast576
void KeccakAbsorb576bits(unsigned char *state, const unsigned char *data)
{
    KeccakPermutationAfterXor(state, data, 72);
}
#endif

#ifdef ProvideFast832
void KeccakAbsorb832bits(unsigned char *state, const unsigned char *data)
{
    KeccakPermutationAfterXor(state, data, 104);
}
#endif

#ifdef ProvideFast1024
void KeccakAbsorb1024bits(unsigned char *state, const unsigned char *data)
{
    KeccakPermutationAfterXor(state, data, 128);
}
#endif

#ifdef ProvideFast1088
void KeccakAbsorb1088bits(unsigned char *state, const unsigned char *data)
{
    KeccakPermutationAfterXor(state, data, 136);
}
#endif

#ifdef ProvideFast1152
void KeccakAbsorb1152bits(unsigned char *state, const unsigned char *data)
{
    KeccakPermutationAfterXor(state, data, 144);
}
#endif

#ifdef ProvideFast1344
void KeccakAbsorb1344bits(unsigned char *state, const unsigned char *data)
{
    KeccakPermutationAfterXor(state, data, 168);
}
#endif

void KeccakAbsorb(unsigned char *state, const unsigned char *data, unsigned int laneCount)
{
    KeccakPermutationAfterXor(state, data, laneCount*8);
}

#ifdef ProvideFast1024
void KeccakExtract1024bits(const unsigned char *state, unsigned char *data)
{
    memcpy(data, state, 128);
}
#endif

void KeccakExtract(const unsigned char *state, unsigned char *data, unsigned int laneCount)
{
    memcpy(data, state, laneCount*8);
}