linux c aes加密

sudo apt-get install libssl-dev

#include <openssl/evp.h>
#include <openssl/rand.h>
#include <string.h>

void handleErrors() {
    ERR_print_errors_fp(stderr);
    abort();
}

int encrypt(unsigned char *plaintext, int plaintext_len, unsigned char *key,
            unsigned char *iv, unsigned char *ciphertext) {
    EVP_CIPHER_CTX *ctx;
    int len;
    int ciphertext_len;

    if(!(ctx = EVP_CIPHER_CTX_new())) handleErrors();
    if(1 != EVP_EncryptInit_ex(ctx, EVP_aes_256_cbc(), NULL, key, iv)) handleErrors();
    if(1 != EVP_EncryptUpdate(ctx, ciphertext, &len, plaintext, plaintext_len)) handleErrors();
    ciphertext_len = len;
    if(1 != EVP_EncryptFinal_ex(ctx, ciphertext + len, &len)) handleErrors();
    ciphertext_len += len;
    EVP_CIPHER_CTX_free(ctx);
    return ciphertext_len;
}

int main() {
    unsigned char key[32];
    unsigned char iv[16];
    unsigned char plaintext[] = "This is a secret message";
    unsigned char ciphertext[128];

    if(!RAND_bytes(key, sizeof(key))) handleErrors();
    if(!RAND_bytes(iv, sizeof(iv))) handleErrors();

    int len = encrypt(plaintext, strlen((char *)plaintext), key, iv, ciphertext);
    printf("Ciphertext is:\n");
    for(int i = 0; i < len; i++) printf("%02x", ciphertext[i]);
    printf("\n");

    return 0;
}

int decrypt(unsigned char *ciphertext, int ciphertext_len, unsigned char *key,
            unsigned char *iv, unsigned char *plaintext) {
    EVP_CIPHER_CTX *ctx;
    int len;
    int plaintext_len;

    if(!(ctx = EVP_CIPHER_CTX_new())) handleErrors();
    if(1 != EVP_DecryptInit_ex(ctx, EVP_aes_256_cbc(), NULL, key, iv)) handleErrors();
    if(1 != EVP_DecryptUpdate(ctx, plaintext, &len, ciphertext, ciphertext_len)) handleErrors();
    plaintext_len = len;
    if(1 != EVP_DecryptFinal_ex(ctx, plaintext + len, &len)) handleErrors();
    plaintext_len += len;
    EVP_CIPHER_CTX_free(ctx);
    return plaintext_len;
}

int main() {
    unsigned char key[32];
    unsigned char iv[16];
    unsigned char ciphertext[] = { /* 这里填入加密后的数据 */ };
    unsigned char decryptedtext[128];

    if(!RAND_bytes(key, sizeof(key))) handleErrors();
    if(!RAND_bytes(iv, sizeof(iv))) handleErrors();

    int len = decrypt(ciphertext, sizeof(ciphertext), key, iv, decryptedtext);
    decryptedtext[len] = '\0';
    printf("Decrypted text is: %s\n", decryptedtext);

    return 0;
}