E3-20260112-pitch/e3_176_ref-buding/middleware/checksum/md5.c

/**
 * @file md5.c
 *
 * Copyright (c) 2021 Semidrive Semiconductor.
 * All rights reserved.
 *
 * Description:compute the md5 of a data stream
 */

#include <md5.h>
#include <string.h>

#include "compiler.h"

#define F1(x, y, z) (z ^ (x & (y ^ z)))
#define F2(x, y, z) F1(z, x, y)
#define F3(x, y, z) (x ^ y ^ z)
#define F4(x, y, z) (y ^ (x | ~z))

#define MD5STEP(f, w, x, y, z, data, s)                                        \
    (w += f(x, y, z) + data, w = w << s | w >> (32 - s), w += x)

static void MD5Transform(unsigned int buf[4], unsigned int const in[16])
{
    register unsigned int a, b, c, d;

    a = buf[0];
    b = buf[1];
    c = buf[2];
    d = buf[3];

    MD5STEP(F1, a, b, c, d, in[0] + 0xd76aa478, 7);
    MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756, 12);
    MD5STEP(F1, c, d, a, b, in[2] + 0x242070db, 17);
    MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceee, 22);
    MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0faf, 7);
    MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62a, 12);
    MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613, 17);
    MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501, 22);
    MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8, 7);
    MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7af, 12);
    MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
    MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22);
    MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7);
    MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12);
    MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17);
    MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22);

    MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562, 5);
    MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340, 9);
    MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14);
    MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20);
    MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105d, 5);
    MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9);
    MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
    MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20);
    MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6, 5);
    MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9);
    MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87, 14);
    MD5STEP(F2, b, c, d, a, in[8] + 0x455a14ed, 20);
    MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5);
    MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9);
    MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9, 14);
    MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);

    MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942, 4);
    MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681, 11);
    MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
    MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23);
    MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44, 4);
    MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11);
    MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16);
    MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
    MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4);
    MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127fa, 11);
    MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085, 16);
    MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05, 23);
    MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039, 4);
    MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
    MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
    MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665, 23);

    MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244, 6);
    MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97, 10);
    MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15);
    MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039, 21);
    MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6);
    MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10);
    MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15);
    MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1, 21);
    MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6);
    MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
    MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314, 15);
    MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
    MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82, 6);
    MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10);
    MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15);
    MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391, 21);

    buf[0] += a;
    buf[1] += b;
    buf[2] += c;
    buf[3] += d;
}

static void byteReverse(unsigned char *buf, unsigned longs)
{
    unsigned int t;

    do {
        t = (unsigned int)((unsigned)buf[3] << 8 | buf[2]) << 16 |
            ((unsigned)buf[1] << 8 | buf[0]);
        *(unsigned int *)buf = t;
        buf += 4;
    } while (--longs);
}

/**
 * @brief Initialize the MD5 context.
 *
 * This function initializes the MD5 context by setting the initial values of
 * the buffer and bit count. The buffer values are set to the predefined
 * constants of the MD5 algorithm, and the bit count is set to zero.
 *
 * @param ctx Pointer to the MD5 context structure to be initialized.
 */
void MD5Init(struct MD5Context *ctx)
{
    ctx->buf[0] = 0x67452301;
    ctx->buf[1] = 0xefcdab89;
    ctx->buf[2] = 0x98badcfe;
    ctx->buf[3] = 0x10325476;

    ctx->bits[0] = 0;
    ctx->bits[1] = 0;
}

/**
 * @brief Update the MD5 context with new data.
 *
 * This function updates the MD5 context with the given data buffer.
 * It processes the data in chunks of 64 bytes, updating the context's bit count
 * and calling the MD5Transform function as necessary.
 *
 * @param ctx Pointer to the MD5 context structure.
 * @param buf Pointer to the input data buffer.
 * @param len Length of the input data buffer in bytes.
 */
void MD5Update(struct MD5Context *ctx, unsigned char const *buf, unsigned len)
{
    register unsigned int t;

    t = ctx->bits[0];

    if ((ctx->bits[0] = t + ((unsigned int)len << 3)) < t)
        ctx->bits[1]++;

    ctx->bits[1] += len >> 29;

    t = (t >> 3) & 0x3f;

    if (t) {
        unsigned char *p = (unsigned char *)ctx->in + t;

        t = 64 - t;

        if (len < t) {
            memmove(p, buf, len);
            return;
        }

        memmove(p, buf, t);
        byteReverse(ctx->in, 16);
        MD5Transform(ctx->buf, (unsigned int *)ctx->in);
        buf += t;
        len -= t;
    }

    while (len >= 64) {
        memmove(ctx->in, buf, 64);
        byteReverse(ctx->in, 16);
        MD5Transform(ctx->buf, (unsigned int *)ctx->in);
        buf += 64;
        len -= 64;
    }

    memmove(ctx->in, buf, len);
}

/**
 * @brief Finalize the MD5 hash computation.
 *
 * This function finalizes the MD5 hash computation by padding the remaining
 * data, appending the bit count, and performing the final MD5 transformation.
 * The resulting hash is stored in the provided digest buffer.
 *
 * @param digest Pointer to the buffer where the 16-byte MD5 digest will be
 * stored.
 * @param ctx Pointer to the MD5 context structure containing the current state
 * of the hash computation.
 */
void MD5Final(unsigned char digest[16], struct MD5Context *ctx)
{
    unsigned int count;
    unsigned char *p;

    count = (ctx->bits[0] >> 3) & 0x3F;

    p = ctx->in + count;
    *p++ = 0x80;

    count = 64 - 1 - count;

    if (count < 8) {
        memset(p, 0, count);
        byteReverse(ctx->in, 16);
        MD5Transform(ctx->buf, (unsigned int *)ctx->in);

        memset(ctx->in, 0, 56);
    } else {
        memset(p, 0, count - 8);
    }

    byteReverse(ctx->in, 14);

    ctx->in32[14] = ctx->bits[0];
    ctx->in32[15] = ctx->bits[1];

    MD5Transform(ctx->buf, (unsigned int *)ctx->in);
    byteReverse((unsigned char *)ctx->buf, 4);
    memmove(digest, ctx->buf, 16);
    memset(ctx, 0, sizeof(*ctx));
}

/**
 * @brief Calculate the MD5 hash of the input data.
 *
 * This function takes an input buffer and its length, and calculates the MD5
 * hash of the data. The resulting 16-byte MD5 hash is stored in the output
 * buffer.
 *
 * @param input Pointer to the input data buffer.
 * @param len Length of the input data buffer in bytes.
 * @param output Pointer to the buffer where the 16-byte MD5 hash will be
 * stored.
 */
void md5(const unsigned char *input, const int len, unsigned char output[16])
{
    struct MD5Context context;
    MD5Init(&context);
    MD5Update(&context, input, len);
    MD5Final(output, &context);
}