最近工作需要使用一些加密算法。之前尝试过cryptopp以及polarssl，听说openssl中的加密模块特别全，并且特别好用。于是想尝试一下。
一、环境配置
下载openssl，我这里使用的是。解压后查看自带的win32说明文件。我这里解压到d盘
按照安装说明。
二、编译静态库
执行命令：
cd D:\openssl-1.0.1s D:perl Configure VC-WIN32 no-asm --prefix=D:\openssl-1.0.1sms\do_ms
有类似输出
然后打开vs2010命令行工具
cd d:\openssl-1.0.1sd:nmake -f ms\nt.mak
等待几分钟，完成后在\out32目录下有静态库文件。
说明：
1.若想生成dll 则将ms\nt.mak 改为ms\ntdll.mak
2.默认情况下，静态库使用的是MT，动态库使用的是MD
3.若想指定MT或MD，修改nt.mak或ntdll.mak 对应CFLAG=内容。
4.若想生成Debug版本的静态库，perl选项设置中修改VC-WIN32为debug-VC-WIN32
三、使用静态库
新建控制台项目
切换Debug生成选项为release
在项目--属性--VC++目录包含目录添加
D:\openssl-1.0.1s\inc32
库目录添加
D:\openssl-1.0.1s\out32;
在项目--属性--C++--连接器--代码生成中修改MD为MT
测试RSA加密解密代码如下：
// testOpenssl.cpp : 定义控制台应用程序的入口点。//#include "stdafx.h"#include#include #include #include #include #include #include #pragma comment(lib, "libeay32.lib")#pragma comment(lib, "ssleay32.lib")// 生成公钥文件和私钥文件，私钥文件带密码int generate_key_files(const char *pub_keyfile, const char *pri_keyfile, const unsigned char *passwd, int passwd_len){ RSA *rsa = NULL; rsa = RSA_generate_key(1024, RSA_F4, NULL, NULL); if(rsa == NULL) { printf("RSA_generate_key error!\n"); return -1; } // 开始生成公钥文件 BIO *bp = BIO_new(BIO_s_file()); if(NULL == bp) { printf("generate_key bio file new error!\n"); return -1; } if(BIO_write_filename(bp, (void *)pub_keyfile) <= 0) { printf("BIO_write_filename error!\n"); return -1; } if(PEM_write_bio_RSAPublicKey(bp, rsa) != 1) { printf("PEM_write_bio_RSAPublicKey error!\n"); return -1; } // 公钥文件生成成功，释放资源 printf("Create public key ok!\n"); BIO_free_all(bp); // 生成私钥文件 bp = BIO_new_file(pri_keyfile, "w+"); if(NULL == bp) { printf("generate_key bio file new error2!\n"); return -1; } if(PEM_write_bio_RSAPrivateKey(bp, rsa, EVP_des_ede3_ofb(), (unsigned char *)passwd, passwd_len, NULL, NULL) != 1) { printf("PEM_write_bio_RSAPublicKey error!\n"); return -1; } // 释放资源 printf("Create private key ok!\n"); BIO_free_all(bp); RSA_free(rsa); return 0;}// 打开公钥文件，返回EVP_PKEY结构的指针EVP_PKEY* open_public_key(const char *keyfile){ EVP_PKEY* key = NULL; RSA *rsa = NULL; OpenSSL_add_all_algorithms(); BIO *bp = BIO_new(BIO_s_file());; BIO_read_filename(bp, keyfile); if(NULL == bp) { printf("open_public_key bio file new error!\n"); return NULL; } rsa = PEM_read_bio_RSAPublicKey(bp, NULL, NULL, NULL); if(rsa == NULL) { printf("open_public_key failed to PEM_read_bio_RSAPublicKey!\n"); BIO_free(bp); RSA_free(rsa); return NULL; } printf("open_public_key success to PEM_read_bio_RSAPublicKey!\n"); key = EVP_PKEY_new(); if(NULL == key) { printf("open_public_key EVP_PKEY_new failed\n"); RSA_free(rsa); return NULL; } EVP_PKEY_assign_RSA(key, rsa); return key;}// 打开私钥文件，返回EVP_PKEY结构的指针EVP_PKEY* open_private_key(const char *keyfile, const unsigned char *passwd){ EVP_PKEY* key = NULL; RSA *rsa = RSA_new(); OpenSSL_add_all_algorithms(); BIO *bp = NULL; bp = BIO_new_file(keyfile, "rb"); if(NULL == bp) { printf("open_private_key bio file new error!\n"); return NULL; } rsa = PEM_read_bio_RSAPrivateKey(bp, &rsa, NULL, (void *)passwd); if(rsa == NULL) { printf("open_private_key failed to PEM_read_bio_RSAPrivateKey!\n"); BIO_free(bp); RSA_free(rsa); return NULL; } printf("open_private_key success to PEM_read_bio_RSAPrivateKey!\n"); key = EVP_PKEY_new(); if(NULL == key) { printf("open_private_key EVP_PKEY_new failed\n"); RSA_free(rsa); return NULL; } EVP_PKEY_assign_RSA(key, rsa); return key;}// 使用密钥加密，这种封装格式只适用公钥加密，私钥解密，这里key必须是公钥int rsa_key_encrypt(EVP_PKEY *key, const unsigned char *orig_data, size_t orig_data_len, unsigned char *enc_data, size_t &enc_data_len){ EVP_PKEY_CTX *ctx = NULL; OpenSSL_add_all_ciphers(); ctx = EVP_PKEY_CTX_new(key, NULL); if(NULL == ctx) { printf("ras_pubkey_encryptfailed to open ctx.\n"); EVP_PKEY_free(key); return -1; } if(EVP_PKEY_encrypt_init(ctx) <= 0) { printf("ras_pubkey_encryptfailed to EVP_PKEY_encrypt_init.\n"); EVP_PKEY_free(key); return -1; } if(EVP_PKEY_encrypt(ctx, enc_data, &enc_data_len, orig_data, orig_data_len) <= 0) { printf("ras_pubkey_encryptfailed to EVP_PKEY_encrypt.\n"); EVP_PKEY_CTX_free(ctx); EVP_PKEY_free(key); return -1; } EVP_PKEY_CTX_free(ctx); EVP_PKEY_free(key); return 0;}// 使用密钥解密，这种封装格式只适用公钥加密，私钥解密，这里key必须是私钥int rsa_key_decrypt(EVP_PKEY *key, const unsigned char *enc_data, size_t enc_data_len, unsigned char *orig_data, size_t &orig_data_len, const unsigned char *passwd){ EVP_PKEY_CTX *ctx = NULL; OpenSSL_add_all_ciphers(); ctx = EVP_PKEY_CTX_new(key, NULL); if(NULL == ctx) { printf("ras_prikey_decryptfailed to open ctx.\n"); EVP_PKEY_free(key); return -1; } if(EVP_PKEY_decrypt_init(ctx) <= 0) { printf("ras_prikey_decryptfailed to EVP_PKEY_decrypt_init.\n"); EVP_PKEY_free(key); return -1; } if(EVP_PKEY_decrypt(ctx, orig_data, &orig_data_len, enc_data, enc_data_len) <= 0) { printf("ras_prikey_decryptfailed to EVP_PKEY_decrypt.\n"); EVP_PKEY_CTX_free(ctx); EVP_PKEY_free(key); return -1; } EVP_PKEY_CTX_free(ctx); EVP_PKEY_free(key); return 0;}int main(){ char enc_text[512] = ""; char dec_text[512] = ""; size_t enc_len = 512; size_t dec_len = 512; //生成密钥对 generate_key_files("public.pem","private.pem",(const unsigned char*)"1234",4); EVP_PKEY* pubkey = open_public_key("public.pem"); EVP_PKEY* prikey = open_private_key("private.pem",(const unsigned char *)"1234"); rsa_key_encrypt(pubkey,(const unsigned char*)"hello",6,(unsigned char*)enc_text,enc_len); rsa_key_decrypt(prikey,(const unsigned char*)enc_text,enc_len,(unsigned char*)dec_text,dec_len,(const unsigned char *)"1234"); printf("%s\n",dec_text); return 0;}