C语言使用openssl大数加减乘除

1.源码实现

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <openssl/bn.h>

int main()
{
        BN_CTX *r[3];
        BIGNUM *a;
        BIGNUM *b;
        BIGNUM *c;
        BIGNUM *d;
        BIGNUM *e;
        BIGNUM *f;
        BIGNUM *g;
        char s[512+1] = "FDBAE7C63C5ECA65D27E9C8759AED3B8F6B36F24773FB6A4A03B49026B2D82491732CFDC9F3C77B61B19A945AA2386A7ABD69F23FBBFE18EDB6B7780A3C4CB13";
        char t[512+1] = "C5C671EBC128B4423C6323DF7E43A1DD35EFCFF0F17B09AD1D6B3FCFBBBB685E6C725BCBC3518B9E067B260C2FE5849F24C839C6AA799732D8B5F8EDC9F286CB";
        char *x;
        char *y;
        char *z;
        char *w;
        char *p;

        r[0] = BN_CTX_new();
        r[1] = BN_CTX_new();
        r[2] = BN_CTX_new();

        //BN_CTX_init(r[0]);
        //BN_CTX_init(r[1]);
        //BN_CTX_init(r[2]);

        a = BN_new();
        b = BN_new();
        c = BN_new();
        d = BN_new();
        e = BN_new();
        f = BN_new();
        g = BN_new();

        BN_hex2bn(&a, s);
        BN_hex2bn(&b, t);

        BN_add(c, a, b);   //加法
        BN_sub(d, a, b);   //减法
        BN_mul(e, a, b, r[0]);  //乘法
        BN_div(f, g, a, b, r[1]);  //除法

        x = BN_bn2hex(c);
        y = BN_bn2hex(d);
        z = BN_bn2hex(e);
        w = BN_bn2hex(f);  //商
        p = BN_bn2hex(g);  //余数

        puts(x);
        puts(y);
        puts(z);
        puts(w);
        puts(p);

        BN_free(a);
        BN_free(b);
        BN_free(c);
        BN_free(d);
        BN_free(e);
        BN_free(f);
        BN_free(g);

        BN_CTX_free(r[0]);
        BN_CTX_free(r[1]);
        BN_CTX_free(r[2]);

        free(x);
        free(y);
        free(z);
        free(w);
        free(p);

        return 0;
}

2.编译源码

$ gcc -I$HOME/local/include -o example example.c -L$HOME/local/lib -lssl

3.运行结果

$ ./example
01C38159B1FD877EA80EE1C066D7F275962CA33F1568BAC051BDA688D226E8EAA783A52BA8628E03542194CF51DA090B46D09ED8EAA63978C1B421706E6DB751DE
37F475DA7B361623961B78A7DB6B31DBC0C39F3385C4ACF782D00932AF7219EAAAC07410DBEAEC18149E83397A3E0208870E655D51464A5C02B57E92D9D24448
C40583D3FA1B2749E39513E018D3097A156E201C5E8AFE6AC17EE858E135A53BFE9B56D53A91D0C4CB777FD6F86A820B58A42BCE427F04B5083BA9E4BF48B3B0487382623B732B0F24FE463F9F602F017F5B8B10A0DADC5588833283569168792C0316AD59F696DB5D5520FB92BB957436C14AB66522647D154ED4CBC24EFA11
01
37F475DA7B361623961B78A7DB6B31DBC0C39F3385C4ACF782D00932AF7219EAAAC07410DBEAEC18149E83397A3E0208870E655D51464A5C02B57E92D9D24448