在密码算法库中,找出关干RSA算法的部分,并且基干标准输入输出,用c++写一段用RSA加密文件的程序
时间: 2023-11-22 09:51:43 浏览: 32
以下是用C++实现RSA加密文件的程序:
```c++
#include <iostream>
#include <fstream>
#include <string>
#include <cstring>
#include <cstdlib>
#include <openssl/rsa.h>
#include <openssl/pem.h>
#include <openssl/err.h>
using namespace std;
int main(int argc, char* argv[]) {
if (argc != 4) {
cout << "Usage: " << argv[0] << " <public_key_file> <input_file> <output_file>" << endl;
return 1;
}
// 读取公钥文件
FILE* public_file = fopen(argv[1], "rb");
if (public_file == NULL) {
cout << "Failed to open public key file: " << argv[1] << endl;
return 2;
}
RSA* rsa = PEM_read_RSA_PUBKEY(public_file, NULL, NULL, NULL);
fclose(public_file);
if (rsa == NULL) {
cout << "Failed to read public key file: " << argv[1] << endl;
ERR_print_errors_fp(stderr);
return 3;
}
// 加载明文文件
ifstream input_file(argv[2], ios::binary | ios::ate);
if (!input_file.is_open()) {
cout << "Failed to open input file: " << argv[2] << endl;
RSA_free(rsa);
return 4;
}
int input_size = input_file.tellg();
char* input_data = new char[input_size];
input_file.seekg(0, ios::beg);
input_file.read(input_data, input_size);
input_file.close();
// 计算加密后密文的长度
int output_size = RSA_size(rsa);
char* output_data = new char[output_size];
// 加密
int result = RSA_public_encrypt(input_size, reinterpret_cast<unsigned char*>(input_data), reinterpret_cast<unsigned char*>(output_data), rsa, RSA_PKCS1_PADDING);
if (result < 0) {
cout << "Failed to encrypt data" << endl;
ERR_print_errors_fp(stderr);
RSA_free(rsa);
delete[] input_data;
delete[] output_data;
return 5;
}
// 保存密文
ofstream output_file(argv[3], ios::binary);
if (!output_file.is_open()) {
cout << "Failed to open output file: " << argv[3] << endl;
RSA_free(rsa);
delete[] input_data;
delete[] output_data;
return 6;
}
output_file.write(output_data, output_size);
output_file.close();
cout << "Encryption complete" << endl;
RSA_free(rsa);
delete[] input_data;
delete[] output_data;
return 0;
}
```
这个程序需要使用到OpenSSL库,需要在编译时链接该库。例如,可以使用以下命令来编译:
```
g++ -o encrypt_rsa_file encrypt_rsa_file.cpp -lssl -lcrypto
```
使用示例:
```
./encrypt_rsa_file public.pem input.txt output.enc
```
其中,public.pem是公钥文件,input.txt是明文文件,output.enc是加密后的密文文件。