http://blog.csdn.net/nadoo/article/details/2156384
这几天做这方面的东西，网上资料很少，贴一个自己试验写的代码，做个记录。
加密：
/*
gcc -o rsa-encrypt rsa-encrypt.c -lcrypto
*/
#include <openssl/rsa.h>#include <openssl/err.h>#define MODULUS "C8FBCF21"#define PUBLIC_EXPONENT RSA_F4#define PRIVATE_EXPONENT "97B55D7D"int main(){ int ret, flen; BIGNUM *bnn, *bne, *bnd; unsigned char *in = "abc"; unsigned char *out; bnn = BN_new(); bne = BN_new(); bnd = BN_new(); BN_hex2bn(&bnn, MODULUS); BN_set_word(bne, PUBLIC_EXPONENT); BN_hex2bn(&bnd, PRIVATE_EXPONENT); RSA *r = RSA_new(); r->n = bnn; r->e = bne; r->d = bnd; RSA_print_fp(stdout, r, 5); flen = RSA_size(r);// - 11; out = (char *)malloc(flen); bzero(out, flen); //memset(out, 0, flen); printf("Begin encrypt... "); ret = RSA_private_encrypt(flen, in, out, r, RSA_NO_PADDING); if (ret < 0)
{ printf("Encrypt failed! "); return 1;
} printf("Size:%d ", ret); printf("ClearText:%s ", in); printf("CipherText(Hex):"); int i; for (i=0; i<ret; i++) { printf("0x%02x, ", *out); out++; } printf(" "); //free(out); RSA_free(r); return 0;}
解密：
/*gcc -o rsa-decrypt rsa-decrypt.c -lcrypto*/#include <openssl/rsa.h>#define MODULUS "C8FBCF21"#define PUBLIC_EXPONENT RSA_F4#define PRIVATE_EXPONENT "97B55D7D"int main(){ int ret, flen; BIGNUM *bnn, *bne; unsigned char in[] = {0x98, 0x79, 0xb2, 0x76}; unsigned char *out; bnn = BN_new(); bne = BN_new(); BN_hex2bn(&bnn, MODULUS); BN_set_word(bne, PUBLIC_EXPONENT); RSA *r = RSA_new(); r->n = bnn; r->e = bne; RSA_print_fp(stdout, r, 5); flen = RSA_size(r); out = (unsigned char *)malloc(flen); bzero(out, flen); printf("Begin decrypt... "); ret = RSA_public_decrypt(sizeof(in), in, out, r, RSA_NO_PADDING); if (ret < 0) { printf("Decrypt failed! "); return 1; } printf("Size:%d ", ret); printf("ClearText:%s ", out); free(out); RSA_free(r); return 0;}