sha3算法C语言实现

以下是SHA-3算法的C语言实现，其中包括SHA3-224、SHA3-256、SHA3-384和SHA3-512。

#include <stdio.h>
#include <stdint.h>

#define ROTL64(x, y) (((x) << (y)) | ((x) >> (64 - (y))))

const uint64_t keccakf_rndc[24] = {
    0x0000000000000001, 0x0000000000008082, 0x800000000000808a,
    0x8000000080008000, 0x000000000000808b, 0x0000000080000001,
    0x8000000080008081, 0x8000000000008009, 0x000000000000008a,
    0x0000000000000088, 0x0000000080008009, 0x000000008000000a,
    0x000000008000808b, 0x800000000000008b, 0x8000000000008089,
    0x8000000000008003, 0x8000000000008002, 0x8000000000000080,
    0x000000000000800a, 0x800000008000000a, 0x8000000080008081,
    0x8000000000008080, 0x0000000080000001, 0x8000000080008008
};

const uint8_t keccakf_rotc[24] = {
    1, 3, 6, 10, 15, 21, 28, 36,
    45, 55, 2, 14, 27, 41, 56, 8,
    25, 43, 62, 18, 39, 61, 20, 44
};

const uint8_t keccakf_piln[24] = {
    10, 7, 11, 17, 18, 3, 5, 16,
    8, 21, 24, 4, 15, 23, 19, 13,
    12, 2, 20, 14, 22, 9, 6, 1
};

void keccakf(uint64_t st[25])
{
    int i, j, r;
    uint64_t t, bc[5];

    for (r = 0; r < 24; r++) {
        for (i = 0; i < 5; i++)
            bc[i] = st[i] ^ st[i + 5] ^ st[i + 10] ^ st[i + 15] ^ st[i + 20];

        for (i = 0; i < 5; i++) {
            t = bc[(i + 4) % 5] ^ ROTL64(bc[(i + 1) % 5], 1);
            for (j = 0; j < 25; j += 5)
                st[j + i] ^= t;
        }

        t = st[1];
        for (i = 0; i < 24; i++) {
            j = keccakf_piln[i];
            bc[0] = st[j];
            st[j] = ROTL64(t, keccakf_rotc[i]);
            t = bc[0];
        }

        for (j = 0; j < 25; j += 5) {
            for (i = 0; i < 5; i++)
                bc[i] = st[j + i];
            for (i = 0; i < 5; i++)
                st[j + i] ^= (~bc[(i + 1) % 5]) & bc[(i + 2) % 5];
        }

        st[0] ^= keccakf_rndc[r];
    }
}

void sha3(const uint8_t *in, int inlen, uint8_t *md, int mdlen)
{
    uint64_t st[25];
    uint8_t temp[200];
    int i;

    for (i = 0; i < 25; i++)
        st[i] = 0;

    while (inlen >= 200) {
        for (i = 0; i < 200 / 8; i++)
            st[i] ^= ((uint64_t *)in)[i];
        keccakf(st);
        in += 200;
        inlen -= 200;
    }

    for (i = 0; i < inlen; i++)
        temp[i] = in[i];
    temp[inlen] = 1;
    inlen++;

    for (i = (inlen + 16) / 17 * 17; i < 200; i++)
        temp[i] = 0;
    temp[200 - 1] |= 0x80;
    for (i = 0; i < 200 / 8; i++)
        st[i] ^= ((uint64_t *)temp)[i];
    keccakf(st);

    for (i = 0; i < mdlen; i++)
        md[i] = st[i / 8] >> 8 * (i % 8);
}

void sha3_224(const uint8_t *in, int inlen, uint8_t *md)
{
    sha3(in, inlen, md, 28);
}

void sha3_256(const uint8_t *in, int inlen, uint8_t *md)
{
    sha3(in, inlen, md, 32);
}

void sha3_384(const uint8_t *in, int inlen, uint8_t *md)
{
    sha3(in, inlen, md, 48);
}

void sha3_512(const uint8_t *in, int inlen, uint8_t *md)
{
    sha3(in, inlen, md, 64);
}

这个实现中，`keccakf()`函数是Keccak-1600置换函数的实现，`sha3()`函数是SHA-3算法的主要实现，而`sha3_224()`、`sha3_256()`、`sha3_384()`和`sha3_512()`函数分别是SHA3-224、SHA3-256、SHA3-384和SHA3-512算法的实现。