用C语言帮我写一个AES256CTR代码
时间: 2023-08-28 14:23:49 浏览: 45
好的,以下是一个使用AES256CTR模式加密和解密的示例代码,使用了OpenSSL库:
```c
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <openssl/aes.h>
int aes256ctr_encrypt(unsigned char *plaintext, int plaintext_len, unsigned char *key,
unsigned char *iv, unsigned char *ciphertext) {
AES_KEY aes_key;
unsigned char ecount_buf[AES_BLOCK_SIZE];
unsigned int num = 0;
if (AES_set_encrypt_key(key, 256, &aes_key) < 0) {
return -1;
}
AES_ctr128_encrypt(plaintext, ciphertext, plaintext_len, &aes_key, iv, ecount_buf, &num);
return 0;
}
int aes256ctr_decrypt(unsigned char *ciphertext, int ciphertext_len, unsigned char *key,
unsigned char *iv, unsigned char *plaintext) {
return aes256ctr_encrypt(ciphertext, ciphertext_len, key, iv, plaintext);
}
int main() {
unsigned char key[] = "01234567890123456789012345678901";
unsigned char iv[] = "1234567890123456";
unsigned char plaintext[] = "Hello, world!";
int plaintext_len = strlen((char *) plaintext);
unsigned char ciphertext[plaintext_len];
unsigned char decryptedtext[plaintext_len];
aes256ctr_encrypt(plaintext, plaintext_len, key, iv, ciphertext);
printf("Ciphertext: ");
for (int i = 0; i < plaintext_len; i++) {
printf("%02x", ciphertext[i]);
}
printf("\n");
aes256ctr_decrypt(ciphertext, plaintext_len, key, iv, decryptedtext);
printf("Decrypted text: %s\n", decryptedtext);
return 0;
}
```
该示例代码使用AES_set_encrypt_key函数设置加密密钥,并使用AES_ctr128_encrypt函数进行加密和解密。注意,在实际应用中,需要确保iv是唯一的,并且每个计数器值只使用一次。