C++ (Cpp) bi_mod_power2 Examples

Example #1

File: ssl_x509.c Project: AbuShaqra/nodemcu-firmware

/**
 * Take a signature and decrypt it.
 */
static bigint *ICACHE_FLASH_ATTR sig_verify(BI_CTX *ctx, const uint8_t *sig, int sig_len,
        bigint *modulus, bigint *pub_exp)
{
    int i, size;
    bigint *decrypted_bi, *dat_bi;
    bigint *bir = NULL;
    uint8_t *block = (uint8_t *)os_malloc(sig_len);

    /* decrypt */
    dat_bi = bi_import(ctx, sig, sig_len);
    ctx->mod_offset = BIGINT_M_OFFSET;

    /* convert to a normal block */
    decrypted_bi = bi_mod_power2(ctx, dat_bi, modulus, pub_exp);

    bi_export(ctx, decrypted_bi, block, sig_len);
    ctx->mod_offset = BIGINT_M_OFFSET;

    i = 10; /* start at the first possible non-padded byte */
    while (block[i++] && i < sig_len);
    size = sig_len - i;

    /* get only the bit we want */
    if (size > 0)
    {
        int len;
        const uint8_t *sig_ptr = get_signature(&block[i], &len);

        if (sig_ptr)
        {
            bir = bi_import(ctx, sig_ptr, len);
        }
    }

    /* save a few bytes of memory */
    bi_clear_cache(ctx);

    os_free(block);
    return bir;
}

Example #2

File: rsa.c Project: tomatoXu/syslinux-rsa-test

/**
 * Take a signature and decrypt it.
**/
bigint *RSA_sign_verify(BI_CTX *ctx, const uint8_t *sig, int sig_len,
        bigint *modulus, bigint *pub_exp)
{
    uint8_t *block;
    int i, size;
    bigint *decrypted_bi, *dat_bi;
    bigint *bir = NULL;

    block = (uint8_t *)malloc(sig_len);

    /* decrypt */
    dat_bi = bi_import(ctx, sig, sig_len);
    ctx->mod_offset = BIGINT_M_OFFSET;

    /* convert to a normal block */
    decrypted_bi = bi_mod_power2(ctx, dat_bi, modulus, pub_exp);

    bi_export(ctx, decrypted_bi, block, sig_len);
    ctx->mod_offset = BIGINT_M_OFFSET;

    i = 10; /* start at the first possible non-padded byte */
    while (block[i++] && i < sig_len);
    size = sig_len - i;

    /* get only the bit we want */
    if (size > 0)
    {
        int len;
        const uint8_t *sig_ptr = x509_get_signature(&block[i], &len);

        if (sig_ptr)
        {
            bir = bi_import(ctx, sig_ptr, len);
        }
    }

    free(block);
    return bir;
}