④ 对加解密函数改造封装

②中的加解密函数，密钥是内部生成的一段数字，打开的文件是程序目录下的

修改后实现输入字符串作为密钥以及文件位置，方便

#pragma comment(lib,"libssl.lib")
#pragma comment(lib,"libcrypto.lib")
#pragma warning(disable:4996)

#include <stdio.h>
#include <string.h>


#include <openssl/evp.h>
#include <openssl/x509.h>

//加密函数
int  Encrypt_File(unsigned char* key,char* path_in)
{
 //   printf("%s\n", key);
//    unsigned char key[EVP_MAX_KEY_LENGTH] = { 0 };  //保存密钥的数组
    unsigned char iv[EVP_MAX_KEY_LENGTH] = { 0 };   //保存初始化向量的数组
    EVP_CIPHER_CTX* ctx = EVP_CIPHER_CTX_new();         //EVP加密上下文环境
    //EVP_CIPHER_CTX_init(&ctx);
    unsigned char out[1024];        //保存密文的缓冲区
    int outl;
    unsigned char in[1024];         //保存原文的缓冲区
    int inl;
    int rv;
    int i;
    FILE* fpIn;
    FILE* fpOut;
    //打开待加密文件
    fpIn = fopen(path_in, "rb");
    if (fpIn == NULL)
    {
        return -1;
    }
    //打开保存密文的文件
    fpOut = fopen("E:\66jia.txt", "wb");
    if (fpOut == NULL)
    {
        fclose(fpIn);
        return -1;
    }
    //设置key和iv
    //for (i = 0; i < 24; i++)
    //{
    //    key[i] = i;
    //}
    for (i = 0; i < 8; i++)
    {
        iv[i] = i;
    }

    //初始化ctx
    EVP_CIPHER_CTX_init(ctx);
    //设置密码算法、key和iv
    rv = EVP_EncryptInit_ex(ctx, EVP_des_ede3_cbc(), NULL, key, iv);
    if (rv != 1)
    {
        printf("Err\n");
        return -1;
    }
    //循环读取原文，加密后后保存到密文文件。
    for (;;)
    {
        inl = fread(in, 1, 1024, fpIn);
        if (inl <= 0)//读取原文结束
            break;
        rv = EVP_EncryptUpdate(ctx, out, &outl, in, inl);//加密
        if (rv != 1)
        {
            fclose(fpIn);
            fclose(fpOut);
            EVP_CIPHER_CTX_cleanup(ctx);
            return -1;
        }
        fwrite(out, 1, outl, fpOut);//保存密文到文件
    }
    //加密结束
    rv = EVP_EncryptFinal_ex(ctx, out, &outl);
    if (rv != 1)
    {
        fclose(fpIn);
        fclose(fpOut);
        EVP_CIPHER_CTX_cleanup(ctx);
        return -1;
    }
    fwrite(out, 1, outl, fpOut);       //保密密文到文件
    fclose(fpIn);
    fclose(fpOut);
    EVP_CIPHER_CTX_cleanup(ctx);   //清除EVP加密上下文环境
    printf("加密已完成\n");
    return 1;
}


//解密函数
int Decrypt_File(unsigned char* key)
{
    //unsigned char key[EVP_MAX_KEY_LENGTH] = { 0 };      //保存密钥的数组
    unsigned char iv[EVP_MAX_KEY_LENGTH] = { 0 };       //保存初始化向量的数组
    EVP_CIPHER_CTX* ctx = EVP_CIPHER_CTX_new();             //EVP加密上下文环境
    unsigned char out[1024 + EVP_MAX_KEY_LENGTH]; //保存解密后明文的缓冲区数组
    int outl;
    unsigned char in[1024];             //保存密文数据的数组
    int inl;
    int rv;
    int i;
    FILE* fpIn;
    FILE* fpOut;

    //打开待解密的密文文件
    fpIn = fopen("mikejmw.txt", "rb");
    if (fpIn == NULL)
    {
        return -1;
    }
    //打开保存明文的文件
    fpOut = fopen("mikejout.txt", "wb");
    if (fpOut == NULL)
    {
        fclose(fpIn);
        return -1;
    }
    //设置key和iv
    //for (i = 0; i < 24; i++)
    //{
    //    key[i] = i;
    //}
    for (i = 0; i < 8; i++)
    {
        iv[i] = i;
    }

    //初始化ctx
    EVP_CIPHER_CTX_init(ctx);
    //设置解密的算法、key和iv
    rv = EVP_DecryptInit_ex(ctx, EVP_des_ede3_cbc(), NULL, key, iv);
    if (rv != 1)
    {
        EVP_CIPHER_CTX_cleanup(ctx);
        return -1;
    }
    //循环读取原文，解密后后保存到明文文件。
    for (;;)
    {
        inl = fread(in, 1, 1024, fpIn);
        if (inl <= 0)
            break;
        rv = EVP_DecryptUpdate(ctx, out, &outl, in, inl);//解密
        if (rv != 1)
        {
            fclose(fpIn);
            fclose(fpOut);
            EVP_CIPHER_CTX_cleanup(ctx);
            return -1;
        }
        fwrite(out, 1, outl, fpOut);//保存明文到文件
    }
    //解密结束
    rv = EVP_DecryptFinal_ex(ctx, out, &outl);
    if (rv != 1)
    {
        fclose(fpIn);
        fclose(fpOut);
        EVP_CIPHER_CTX_cleanup(ctx);
        return -1;
    }
    fwrite(out, 1, outl, fpOut);//保存明文到文件
    fclose(fpIn);
    fclose(fpOut);
    EVP_CIPHER_CTX_cleanup(ctx);//清除EVP加密上下文环境
    printf("解密已完成\n");
    return 1;
}

int main()
{

    OpenSSL_add_all_algorithms();
    
    unsigned char key[EVP_MAX_KEY_LENGTH];
    char path_in[100];
    path_in[100];
    scanf("%s", path_in);
    scanf("%s", key);
 //   printf("%s\n", key);

 //   printf("%s\n", path_in);
    Encrypt_File(key,path_in);
    //Decrypt_File(key);


    return 0;
}

后续调用

标签：封装,函数,fpIn,ctx,加解密,unsigned,char,key,EVP
来源： https://www.cnblogs.com/51ggh/p/16311206.html