RSA 加密解密简单案列 Openssl 1.1.1 C语言实现
一、直接复制公钥私钥到代码里
代码
main.c
#include "crypto.h"
int main(int argc, char* argv[])
{
char* cleartext = "123abc";
if (sizeof(cleartext) > 256) {
printf("cleartext too length!!!");
return -1;
}
RSA_test1(cleartext);
//RSA_test2(cleartext);
printf("ok");
return 0;
}
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crypto.c
#include "crypto.h"
#define KEY_LENGTH 2048
int padding = RSA_PKCS1_PADDING;
int encrypt_len = 0;
#define PUB_EXP 3
int GenerateRSAKey(char* strKey[])
{
size_t pri_len; // Length of private key
size_t pub_len; // Length of public key
RSA* keypair = RSA_generate_key(KEY_LENGTH, RSA_3, NULL, NULL);
BIO *pri = BIO_new(BIO_s_mem());
BIO *pub = BIO_new(BIO_s_mem());
PEM_write_bio_RSAPrivateKey(pri, keypair, NULL, NULL, 0, NULL, NULL);
PEM_write_bio_RSAPublicKey(pub, keypair);
pri_len = BIO_pending(pri);
pub_len = BIO_pending(pub);
char pri_key[pri_len + 1]; // Private key
char pub_key[pub_len + 1]; // Public key
BIO_read(pri, pri_key, pri_len);
BIO_read(pub, pub_key, pub_len);
pri_key[pri_len] = ' ';
pub_key[pub_len] = ' ';
strKey[0] = pub_key;
strKey[1] = pri_key;
RSA_free(keypair);
BIO_free_all(pub);
BIO_free_all(pri);
return 0;
}
RSA* createRSA(unsigned char* key, int flag)
{
RSA *rsa= NULL;
BIO *keybio ;
keybio = BIO_new_mem_buf(key, -1);
if (keybio==NULL) {
printf( "Failed to create key BIO");
return 0;
}
if(flag)
rsa = PEM_read_bio_RSA_PUBKEY(keybio, &rsa, NULL, NULL);
else
rsa = PEM_read_bio_RSAPrivateKey(keybio, &rsa, NULL, NULL);
if(rsa == NULL)
printf( "Failed to create RSA");
return rsa;
}
int public_encrypt(unsigned char* data, int data_len, unsigned char* key, unsigned char* encrypted)
{
RSA * rsa = createRSA(key, 1);
int result = RSA_public_encrypt(data_len, data, encrypted, rsa, padding);
return result;
}
int private_decrypt(unsigned char* enc_data, int data_len, unsigned char* key, unsigned char* decrypted)
{
RSA * rsa = createRSA(key, 0);
int result = RSA_private_decrypt(data_len,enc_data,decrypted,rsa,padding);
return result;
}
int private_encrypt(unsigned char* data, int data_len, unsigned char* key, unsigned char* encrypted)
{
RSA * rsa = createRSA(key, 0);
int result = RSA_private_encrypt(data_len, data, encrypted, rsa, padding);
return result;
}
int public_decrypt(unsigned char* enc_data, int data_len, unsigned char* key, unsigned char* decrypted)
{
RSA * rsa = createRSA(key, 1);
int result = RSA_public_decrypt(data_len, enc_data, decrypted, rsa, padding);
return result;
}
void printLastError(char *msg)
{
char * err = (char*)malloc(130);;
ERR_load_crypto_strings();
ERR_error_string(ERR_get_error(), err);
printf("%%s ERROR: %%s
", msg, err);
free(err);
}
void RSA_test1(const char* cleartext)
{
char* plainText = cleartext;
//下面的公钥和私钥是通过命令行方式获取的
char* publicKey = "-----BEGIN PUBLIC KEY-----
"
"MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAy8Dbv8prpJ/0kKhlGeJY
"
"ozo2t60EG8L0561g13R29LvMR5hyvGZlGJpmn65+A4xHXInJYiPuKzrKUnApeLZ+
"
"vw1HocOAZtWK0z3r26uA8kQYOKX9Qt/DbCdvsF9wF8gRK0ptx9M6R13NvBxvVQAp
"
"fc9jB9nTzphOgM4JiEYvlV8FLhg9yZovMYd6Wwf3aoXK891VQxTr/kQYoq1Yp+68
"
"i6T4nNq7NWC+UNVjQHxNQMQMzU6lWCX8zyg3yH88OAQkUXIXKfQ+NkvYQ1cxaMoV
"
"PpY72+eVthKzpMeyHkBn7ciumk5qgLTEJAfWZpe4f4eFZj/Rc8Y8Jj2IS5kVPjUy
"
"wQIDAQAB
"
"-----END PUBLIC KEY-----
";
char* privateKey = "-----BEGIN RSA PRIVATE KEY-----
"
"MIIEowIBAAKCAQEAy8Dbv8prpJ/0kKhlGeJYozo2t60EG8L0561g13R29LvMR5hy
"
"vGZlGJpmn65+A4xHXInJYiPuKzrKUnApeLZ+vw1HocOAZtWK0z3r26uA8kQYOKX9
"
"Qt/DbCdvsF9wF8gRK0ptx9M6R13NvBxvVQApfc9jB9nTzphOgM4JiEYvlV8FLhg9
"
"yZovMYd6Wwf3aoXK891VQxTr/kQYoq1Yp+68i6T4nNq7NWC+UNVjQHxNQMQMzU6l
"
"WCX8zyg3yH88OAQkUXIXKfQ+NkvYQ1cxaMoVPpY72+eVthKzpMeyHkBn7ciumk5q
"
"gLTEJAfWZpe4f4eFZj/Rc8Y8Jj2IS5kVPjUywQIDAQABAoIBADhg1u1Mv1hAAlX8
"
"omz1Gn2f4AAW2aos2cM5UDCNw1SYmj+9SRIkaxjRsE/C4o9sw1oxrg1/z6kajV0e
"
"N/t008FdlVKHXAIYWF93JMoVvIpMmT8jft6AN/y3NMpivgt2inmmEJZYNioFJKZG
"
"X+/vKYvsVISZm2fw8NfnKvAQK55yu+GRWBZGOeS9K+LbYvOwcrjKhHz66m4bedKd
"
"gVAix6NE5iwmjNXktSQlJMCjbtdNXg/xo1/G4kG2p/MO1HLcKfe1N5FgBiXj3Qjl
"
"vgvjJZkh1as2KTgaPOBqZaP03738VnYg23ISyvfT/teArVGtxrmFP7939EvJFKpF
"
"1wTxuDkCgYEA7t0DR37zt+dEJy+5vm7zSmN97VenwQJFWMiulkHGa0yU3lLasxxu
"
"m0oUtndIjenIvSx6t3Y+agK2F3EPbb0AZ5wZ1p1IXs4vktgeQwSSBdqcM8LZFDvZ
"
"uPboQnJoRdIkd62XnP5ekIEIBAfOp8v2wFpSfE7nNH2u4CpAXNSF9HsCgYEA2l8D
"
"JrDE5m9Kkn+J4l+AdGfeBL1igPF3DnuPoV67BpgiaAgI4h25UJzXiDKKoa706S0D
"
"4XB74zOLX11MaGPMIdhlG+SgeQfNoC5lE4ZWXNyESJH1SVgRGT9nBC2vtL6bxCVV
"
"WBkTeC5D6c/QXcai6yw6OYyNNdp0uznKURe1xvMCgYBVYYcEjWqMuAvyferFGV+5
"
"nWqr5gM+yJMFM2bEqupD/HHSLoeiMm2O8KIKvwSeRYzNohKTdZ7FwgZYxr8fGMoG
"
"PxQ1VK9DxCvZL4tRpVaU5Rmknud9hg9DQG6xIbgIDR+f79sb8QjYWmcFGc1SyWOA
"
"SkjlykZ2yt4xnqi3BfiD9QKBgGqLgRYXmXp1QoVIBRaWUi55nzHg1XbkWZqPXvz1
"
"I3uMLv1jLjJlHk3euKqTPmC05HoApKwSHeA0/gOBmg404xyAYJTDcCidTg6hlF96
"
"ZBja3xApZuxqM62F6dV4FQqzFX0WWhWp5n301N33r0qR6FumMKJzmVJ1TA8tmzEF
"
"yINRAoGBAJqioYs8rK6eXzA8ywYLjqTLu/yQSLBn/4ta36K8DyCoLNlNxSuox+A5
"
"w6z2vEfRVQDq4Hm4vBzjdi3QfYLNkTiTqLcvgWZ+eX44ogXtdTDO7c+GeMKWz4XX
"
"uJSUVL5+CVjKLjZEJ6Qc2WZLl94xSwL71E41H4YciVnSCQxVc4Jw
"
"-----END RSA PRIVATE KEY-----
";
unsigned char encrypted[4098] = {};
unsigned char decrypted[4098] = {};
int encrypted_length= public_encrypt((unsigned char*)plainText,sizeof(plainText), (unsigned char*)publicKey, encrypted);
if (encrypted_length == -1) {
printLastError("Public Encrypt failed ");
exit(0);
}
char res[4098] = {0};
for(int i = 0;i < 4098 && encrypted[i] != ' ';i++)
{
printf("%%d",encrypted[i]);
}
printf("
Encrypted length =%%d
", encrypted_length);
int decrypted_length = private_decrypt(encrypted, encrypted_length, (unsigned char*)privateKey, decrypted);
if (decrypted_length == -1) {
printLastError("Private Decrypt failed ");
exit(0);
}
printf("Decrypted Text =%%s
", decrypted);
printf("Decrypted Length =%%d
", decrypted_length);
encrypted_length= private_encrypt((unsigned char*)plainText, sizeof(plainText),(unsigned char*)privateKey, encrypted);
if(encrypted_length == -1) {
printLastError("Private Encrypt failed");
exit(0);
}
printf("Encrypted length =%%d
", encrypted_length);
decrypted_length = public_decrypt(encrypted, encrypted_length, (unsigned char*)publicKey, decrypted);
if(decrypted_length == -1) {
printLastError("Public Decrypt failed");
exit(0);
}
printf("Decrypted Text =%%s
", decrypted);
printf("Decrypted Length =%%d
", decrypted_length);
}
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crypto.h
#ifndef _CRYPTOTEST_H_
#define _CRYPTOTEST_H_
#include <string.h>
#include <stdio.h>
#include <openssl/pem.h>
#include <openssl/err.h>
#include <openssl/rsa.h>
typedef enum {
GENERAL = 0,
ECB,
CBC,
CFB,
OFB,
TRIPLE_ECB,
TRIPLE_CBC
}CRYPTO_MODE;
int GenerateRSAKey(char* strKey[]);
void RSA_test1(const char* cleartext);
#endif //_CRYPTOTEST_H_
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gcc编译
gcc main.c crypto.c -o main.out -std=c99 -L /home/openssl-1.1.1l -l ssl -l crypto
- 1
执行该命令的前提是下载并解压了openssl资源包,可参考下面的教程
openssl的编译和使用
运行结果
二、读取pem文件后加密解密
代码
encry.c
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<openssl/rsa.h>
#include<openssl/pem.h>
#include<openssl/err.h>
#define PRIKEY "private_key.pem"
#define PUBKEY "public_key.pem"
#define BUFFSIZE 4096
/************************************************************************
* RSA加密解密函数
*
* file: test_rsa_encdec.c
* gcc -Wall -O2 -o test_rsa_encdec test_rsa_encdec.c -lcrypto -lssl
*
* author: tonglulin@gmail.com by www.qmailer.net
************************************************************************/
char*my_encrypt(char*str,char*pubkey_path)
{
RSA *rsa = NULL;
FILE*fp = NULL;
char*en = NULL;
int len = 0;
int rsa_len = 0;
if((fp = fopen(pubkey_path,"r")) == NULL) {
return NULL;
}
/* 读取公钥PEM,PUBKEY格式PEM使用PEM_read_RSA_PUBKEY函数 */
if((rsa = PEM_read_RSAPublicKey(fp, NULL, NULL, NULL)) == NULL) {
return NULL;
}
RSA_print_fp(stdout, rsa, 0);
len = strlen(str);
rsa_len = RSA_size(rsa);
en = (char*)malloc(rsa_len + 1);
memset(en, 0, rsa_len + 1);
if(RSA_public_encrypt(rsa_len, (unsigned char*)str, (unsigned char*)en, rsa, RSA_NO_PADDING) < 0) {
return NULL;
}
RSA_free(rsa);
fclose(fp);
return en;
}
char*my_decrypt(char*str,char*prikey_path)
{
RSA *rsa = NULL;
FILE*fp = NULL;
char*de = NULL;
int rsa_len = 0;
if((fp = fopen(prikey_path,"r")) == NULL) {
return NULL;
}
if((rsa = PEM_read_RSAPrivateKey(fp, NULL, NULL, NULL)) == NULL) {
return NULL;
}
RSA_print_fp(stdout, rsa, 0);
rsa_len = RSA_size(rsa);
de = (char*)malloc(rsa_len + 1);
memset(de, 0, rsa_len + 1);
if(RSA_private_decrypt(rsa_len, (unsigned char*)str, (unsigned char*)de, rsa, RSA_NO_PADDING) < 0) {
return NULL;
}
RSA_free(rsa);
fclose(fp);
return de;
}
int main(int argc,char*argv[])
{
char*src = "hello, world!";
char*en = NULL;
char*de = NULL;
printf("src is: %%s
", src);
en = my_encrypt(src, PUBKEY);
printf("enc is: %%s
", en);
de= my_decrypt(en, PRIKEY);
printf("dec is: %%s
", de);
if(en != NULL) {
free(en);
}
if(de != NULL) {
free(de);
}
return 0;
}
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编译
gcc encry.c -o encry.out -std=c99 -L /home/openssl-1.1.1l -l ssl -l crypto
- 1
执行这个命令需要两个pem文件,路径在代码中指出了,生成pem文件的命令可参考:
openssl生成pem格式公私钥文件
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