用RSA加密AES的密钥k,后用AES加密数据c语言实现

下面是用C语言实现RSA加密AES密钥k，然后用AES加密数据c的示例代码：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <openssl/rsa.h>
#include <openssl/pem.h>
#include <openssl/evp.h>
#include <openssl/aes.h>

#define KEY_LENGTH 2048
#define AES_BLOCK_SIZE 16

int main() {
    // 生成RSA密钥对
    RSA *rsa = RSA_generate_key(KEY_LENGTH, RSA_F4, NULL, NULL);
    
    // 生成AES密钥
    unsigned char aes_key[AES_BLOCK_SIZE];
    if (!RAND_bytes(aes_key, AES_BLOCK_SIZE)) {
        printf("Failed to generate AES key\n");
        return 1;
    }
    
    // RSA加密AES密钥
    int rsa_len = RSA_size(rsa);
    unsigned char encrypted_key[rsa_len];
    int encrypted_len = RSA_public_encrypt(AES_BLOCK_SIZE, aes_key, encrypted_key, rsa, RSA_PKCS1_PADDING);
    if (encrypted_len == -1) {
        printf("Failed to encrypt AES key\n");
        return 1;
    }
    
    // 使用AES加密数据
    unsigned char plaintext[] = "Hello, world!";
    int plaintext_len = strlen(plaintext);
    int ciphertext_len = 0;
    unsigned char iv[AES_BLOCK_SIZE];
    if (!RAND_bytes(iv, AES_BLOCK_SIZE)) {
        printf("Failed to generate IV\n");
        return 1;
    }
    unsigned char ciphertext[plaintext_len + AES_BLOCK_SIZE];
    AES_KEY aes;
    if (AES_set_encrypt_key(aes_key, AES_BLOCK_SIZE * 8, &aes) < 0) {
        printf("Failed to set AES encryption key\n");
        return 1;
    }
    AES_cbc_encrypt(plaintext, ciphertext, plaintext_len, &aes, iv, AES_ENCRYPT);
    ciphertext_len = plaintext_len + AES_BLOCK_SIZE;
    
    // 输出结果
    printf("RSA encrypted AES key: ");
    for (int i = 0; i < encrypted_len; i++) {
        printf("%02x", encrypted_key[i]);
    }
    printf("\n");
    printf("AES encrypted ciphertext: ");
    for (int i = 0; i < ciphertext_len; i++) {
        printf("%02x", ciphertext[i]);
    }
    printf("\n");
    
    // 释放内存
    RSA_free(rsa);
    
    return 0;
}

注意，上述代码需要引入OpenSSL库。可以使用以下命令进行编译：

gcc -o encrypt encrypt.c -lcrypto

其中，encrypt.c是包含上述代码的文件名，-lcrypto参数用于链接OpenSSL库。

需要注意的是，上述代码只是示例代码，实际使用时需要考虑更多的安全性问题，如密钥管理、数据完整性校验等。