openssl aes-256 cfb128使用

#include <openssl/aes.h>
#include <openssl/evp.h>
#include <iostream>
#include <string.h>

using namespace std;

int main()
{
    /* ckey and ivec are the two 128-bits keys necessary to
       en- and recrypt your data.  Note that ckey can be
       192 or 256 bits as well
     */

    unsigned char ckey[] =  "helloworldkey";
    unsigned char ivec[] = "goodbyworldkeya"; //注意是16字节含\0
    unsigned char ivec2[] = "goodbyworldkeya"; //注意是16字节含\0

    int bytes_read;
    unsigned char indata[AES_BLOCK_SIZE];
    unsigned char outdata[AES_BLOCK_SIZE];
    unsigned char decryptdata[AES_BLOCK_SIZE];

    /* data structure that contains the key itself */
    AES_KEY keyEn;

    /* set the encryption key */
    AES_set_encrypt_key(ckey, 128, &keyEn);

    /* set where on the 128 bit encrypted block to begin encryption*/
    int num = 0;

    strcpy( (char*)indata , "Hello World" );
    bytes_read = sizeof(indata);

    AES_cfb128_encrypt(indata, outdata, bytes_read, &keyEn, ivec, &num, AES_ENCRYPT);
    cout << "original data:\t" << indata << endl;
    cout << "encrypted data:\t" << outdata << endl;
    

    num = 0;
    AES_cfb128_encrypt(outdata, decryptdata, bytes_read, &keyEn, ivec2, &num, AES_DECRYPT);
    cout << "input data was:\t" << decryptdata << endl;
    return 0;
}