OpenSSL EVP

OpenSSL EVP"/>

OpenSSL EVP

#include <stdio.h>
#include <string.h>
#include <openssl/evp.h>
#include <openssl/x509.h>void tEVP_Encrypt()
{unsigned char key[EVP_MAX_KEY_LENGTH];	//密钥unsigned char iv[EVP_MAX_KEY_LENGTH];//初始化向量EVP_CIPHER_CTX ctx;//EVP算法上下文unsigned char out[1024];//输出密文缓冲区unsigned char out1[1024];//输出明文缓冲区int outl;//密文长度int outltmp;int outl1;//明文长度int outltmp1;char *msg="Hello OpenSSL! I am xxh!!!";//待加密的数据int rv;int rv1;int i;//加密过程//设置key和iv（可以采用随机数和可以是用户输入）for(i=0;i<24;i++){key[i]=i;}for(i=0;i<8;i++){iv[i]=i;}//初始化密码算法结构体EVP_CIPHER_CTX_init(&ctx);//设置算法和密钥rv = EVP_EncryptInit_ex(&ctx,EVP_des_ede3_cbc(),NULL,key,iv);if(rv!=1){printf("Err\n");return;}//数据加密rv = EVP_EncryptUpdate(&ctx,out,&outl,msg,strlen(msg));if(rv!=1){printf("Err\n");return;}//结束数据加密，把剩余数据输出。rv = EVP_EncryptFinal_ex(&ctx,out+outl,&outltmp);if(rv!=1){printf("Err\n");return;}outl = outl +outltmp;	printf("原文为:%s\n",msg);//打印输出密文printf("密文长度：%d\n密文数据：\n",outl);for(i=0;i<outl;i++){printf("0x%02x ",out[i]);}printf("\n");//解密过程rv1 = EVP_DecryptInit_ex(&ctx,EVP_des_ede3_cbc(),NULL,key,iv);if(rv1!=1){printf("Err1\n");return;}rv1 = EVP_DecryptUpdate(&ctx,out1,&outl1,out,outl);if(rv1!=1){printf("Err2\n");return;}rv1 = EVP_DecryptFinal_ex(&ctx,out1+outl1,&outltmp1);if(rv1!=1){printf("Err3\n");return;}outl1 = outl1 +outltmp1;//打印输出明文printf("\n\n原文长度：%d\n原文数据：\n",outl1);for(i=0;i<outl1;i++){printf("%c",out1[i]);}printf("\n");
}int main()
{ OpenSSL_add_all_algorithms();tEVP_Encrypt();return 0;
}