openssl AES-CBC 加密解密问题 IV 如何保存下来。

2016-12-14 04:57:33 838 阅读 AI 写同款 · GEO 优化AI 选题数据监测一键分发 ›

使用openssl加解密文件（aes-128-cbc）关于openssl的使用，在网上的例子都比较简单，有一些很难理解，由于我做的项目中有使用，所以将一些心得展开给大家。在进行文件加密时，如果没有特别的要求，推荐使用对称加密方法（aes-128-cbc），详细使用如下： 1. 首先我们需要准备被加密的文件和数据。 echo "AABBCCDDEEFFGGHHMMNNOOPPQQ" > input.bin 2. 因为我们要使用aes... 阅读详情

用户密码加密，解密我用到了 OPENSSL AES-CBC 加密模式。不管是加密还是解密，我的密钥都是固定的。但是我加密以后的iv是不是需要保存下来？因为我把加密后的数据进行解密，不能正确的解密，解密出来是乱码。

加密：

#include <stdio.h>

#include <string.h>

#include <stdlib.h>

#include <openssl/aes.h>

 

int main(int argc, char** argv) {

    AES_KEY aes;

    unsigned char* key = "www.qqqqqqq.com ";        // AES_BLOCK_SIZE = 16

    unsigned char iv[AES_BLOCK_SIZE];        // init vector

    unsigned char* input_string;

    unsigned char* encrypt_string;

    unsigned int len;        // encrypt length (in multiple of AES_BLOCK_SIZE)

    unsigned int i;

 

    // check usage

    if (argc != 2) {

        fprintf(stderr, "%s <plain text>\n", argv[0]);

        exit(-1);

    }

 

    // set the encryption length

    len = 0;

    if ((strlen(argv[1]) + 1) % AES_BLOCK_SIZE == 0) {

        len = strlen(argv[1]) + 1;

    } else {

        len = ((strlen(argv[1]) + 1) / AES_BLOCK_SIZE + 1) * AES_BLOCK_SIZE;

    }

 

    // set the input string

    input_string = (unsigned char*)calloc(len, sizeof(unsigned char));

    if (input_string == NULL) {

        fprintf(stderr, "Unable to allocate memory for input_string\n");

        exit(-1);

    }

    strncpy((char*)input_string, argv[1], strlen(argv[1]));

 

    // Generate AES 128-bit key

    /*for (i=0; i<16; ++i) {

        key[i] = 32 + i;

    }*/

 

    // Set encryption key

    for (i=0; i<AES_BLOCK_SIZE; ++i) {

        iv[i] = 0;

    }

    if (AES_set_encrypt_key(key, 128, &aes) < 0) {

        fprintf(stderr, "Unable to set encryption key in AES\n");

        exit(-1);

    }

 

    // alloc encrypt_string

    encrypt_string = (unsigned char*)calloc(len, sizeof(unsigned char));    

    if (encrypt_string == NULL) {

        fprintf(stderr, "Unable to allocate memory for encrypt_string\n");

        exit(-1);

    }

    

    // encrypt (iv will change)

    AES_cbc_encrypt(input_string, encrypt_string, len, &aes, iv, AES_ENCRYPT);

    

    // print

    for (i=0; i<len; ++i) {

        printf("%X%X", (encrypt_string[i] >> 4) & 0xf, 

                encrypt_string[i] & 0xf);    

    }

    printf("\n");

 

    return 0;

}

解密：

#include <stdio.h>

#include <string.h>

#include <stdlib.h>

#include <openssl/aes.h>

 

int main(int argc, char** argv) {

    AES_KEY aes;

    unsigned char* key = "www.qqqqqqq.com ";        // AES_BLOCK_SIZE = 16

    unsigned char iv[AES_BLOCK_SIZE];        // init vector

    unsigned char* input_string;

    unsigned char* decrypt_string;

    unsigned int len;        // encrypt length (in multiple of AES_BLOCK_SIZE)

    unsigned int i;

 

    // check usage

    if (argc != 2) {

        fprintf(stderr, "%s <plain text>\n", argv[0]);

        exit(-1);

    }

 

    // set the encryption length

    len = 0;

    if ((strlen(argv[1]) + 1) % AES_BLOCK_SIZE == 0) {

        len = strlen(argv[1]) + 1;

    } else {

        len = ((strlen(argv[1]) + 1) / AES_BLOCK_SIZE + 1) * AES_BLOCK_SIZE;

    }

 

    // set the input string

    input_string = (unsigned char*)calloc(len, sizeof(unsigned char));

    if (input_string == NULL) {

        fprintf(stderr, "Unable to allocate memory for input_string\n");

        exit(-1);

    }

    strncpy((char*)input_string, argv[1], strlen(argv[1]));

 

    // alloc decrypt_string

    decrypt_string = (unsigned char*)calloc(len, sizeof(unsigned char));

    if (decrypt_string == NULL) {

        fprintf(stderr, "Unable to allocate memory for decrypt_string\n");

        exit(-1);

    }

 

    // Set decryption key

    for (i=0; i<AES_BLOCK_SIZE; ++i) {

        iv[i] = 0;

    }

    if (AES_set_decrypt_key(key, 128, &aes) < 0) {

        fprintf(stderr, "Unable to set decryption key in AES\n");

        exit(-1);

    }

 

    // decrypt

    AES_cbc_encrypt(input_string, decrypt_string, len, &aes, iv, 

            AES_DECRYPT);

 

    printf("%s", decrypt_string);

 	printf("\n");

    return 0;

}