1.源码实现

#include <stdio.h>
#include <string.h>
#include <openssl/ecdsa.h>
#include <openssl/pem.h>
#include <openssl/err.h>
struct ECDSA_SIG_st {
    BIGNUM *r;
    BIGNUM *s;
//公钥验证签名
int my_verify(const char *input, int input_len, ECDSA_SIG *signret, const char *pub_key_fn)
        EC_KEY *p_dsa = NULL;
        FILE *file = NULL;
        int ret = 0;
        if((file = fopen(pub_key_fn, "rb")) == NULL)
                ret = -1;
                return ret;
        if((p_dsa = PEM_read_EC_PUBKEY(file, NULL,NULL,NULL )) == NULL)
                ret = -2;
                fclose(file);
                return ret;
        fclose(file);
        ret = ECDSA_do_verify(input, input_len, signret, p_dsa);
        if(ret != 1)
                ret = -3;
                printf("ECDSA_verify err!\n");
                EC_KEY_free(p_dsa);
                return ret;
        printf("verify is ok!\n");
        EC_KEY_free(p_dsa);
        return 0;
//私钥签名
int my_sign(const char *input, int input_len, const char *pri_key_fn)
        EC_KEY *p_dsa = NULL;
        ECDSA_SIG *s;
        FILE *file = NULL;
        unsigned char *data[2];
        int nid;
        int signlen = 0;
        int i = 0;
        int ret = 0;
        memset(data, 0x00, sizeof(data));
        nid = 0;
        file = fopen(pri_key_fn, "rb");
        if(!file)
                ret = -1;
                return ret;
        if((p_dsa = PEM_read_ECPrivateKey(file, NULL, NULL, NULL)) == NULL)
                ret = -2;
                fclose(file);
                return ret;
        fclose(file);
        s = ECDSA_do_sign(input, input_len, p_dsa);
        if(s == NULL)
                ret = -3;
                EC_KEY_free(p_dsa);
                return ret;
        data[0] = BN_bn2hex(s->r);
        data[1] = BN_bn2hex(s->s);
        EC_KEY_free(p_dsa);
        ECDSA_SIG_free(s);
        printf("%s\n", data[0]);
        printf("%s\n", data[1]);
        free(data[0]);
        free(data[1]);
        return 0;
int main(int argc, char**argv)
        char src[512+1];
        char dst_str[2][512+1];
        int src_len;
        int ret;
        FILE *f;
        memset(src, 0x00, sizeof(src));
        //memset(dst, 0x00, sizeof(dst));
        if(argv[1][0] == 's')
                strcpy(src, "aedewderdfercfrtvgfrtfgrtgfrtgvtrgtrvgtyebtybytbnybyuyubndrybrfgswdhyewhde");
                src_len = strlen(src) ;
                ret = my_sign(src, src_len, argv[2]);
                if(ret)
                        fprintf(stderr, "Error\n");
                ECDSA_SIG *s = (ECDSA_SIG *)malloc(sizeof(ECDSA_SIG));
                strcpy(src, "aedewderdfercfrtvgfrtfgrtgfrtgvtrgtrvgtyebtybytbnybyuyubndrybrfgswdhyewhde");
                strncpy(dst_str[0], argv[2], 512);
                strncpy(dst_str[1], argv[3], 512);
                src_len = strlen(src);
                s->r = BN_new();
                s->s = BN_new();
                BN_hex2bn(&(s->r), dst_str[0]);
                BN_hex2bn(&(s->s), dst_str[1]);
                ret = my_verify(src, src_len, s, argv[1]);
                if(ret)
                        fprintf(stderr, "Error\n");
                BN_free(s->r);
                BN_free(s->s);
                free(s);
        return 0;
2.编译源码
$ gcc -I$HOME/local/include -o example example.c -L$HOME/local/lib -lssl
3.生成私钥和公钥
$ openssl ecparam -genkey -name prime256v1 -out eccpri256.key
$ openssl ec -in eccpri256.key -pubout -out eccpri256.pem
4.运行结果
$ ./example s eccpri256.key