在输入文件中我有:
第一行是一个以十六进制编码的密钥,长度为 16 个字节;
在第二行加密消息(CBC 模式下的 AES128,在加密消息前面添加随机 iv)。
这就是我尝试解密的方法:
#include<iostream>
using namespace std;
#include <fstream>
#include <string.h>
#include <cryptopp/aes.h>
#include <cryptopp/modes.h>
#include <cryptopp/filters.h>
using namespace CryptoPP;
int main(void) {
ifstream in("input0.txt");
ofstream out("output0.txt");
string hex_key = "", hex_ct = "";
in >> hex_key >> hex_ct;
byte key[ AES::DEFAULT_KEYLENGTH ], iv[ AES::BLOCKSIZE ];
string ciphertext = "", recoveredtext = "";
for(int i = 0; i < hex_key.size(); i+=2) {
key[i/2] = (char) strtol((hex_key.substr(i, 2)).c_str(), 0, 16);
}
//then I divide iv from the text
for(int i = 0; i < AES::BLOCKSIZE*2; i+=2) {
iv[i/2] = (char) strtol((hex_ct.substr(i, 2)).c_str(), 0, 16);
}
for(int i = AES::BLOCKSIZE*2; i < hex_ct.size(); i++) {
ciphertext.push_back(hex_ct[i]);
}
//decryption
CBC_Mode< AES >::Decryption d;
d.SetKeyWithIV(key, AES::DEFAULT_KEYLENGTH, iv);
StringSink sink( recoveredtext );
StreamTransformationFilter stf (
d,
&sink
);
StringSource ss (
ciphertext,
true,
&stf
);
out << recoveredtext;
return 0;
}
我按照以下方式使用了这个实现 Wiki https://www.cryptopp.com/wiki/CBC_mode.
我也尝试过 this https://stackoverflow.com/questions/12306956/example-of-aes-using-crypto它有效,但没有用 my 替换密钥和密文。
好吧,使用上面的代码我有这样的输出:
AES128CBC: /usr/local/include/cryptopp/misc.h:304: void CryptoPP::memcpy_s(void*, size_t, const void*, size_t): Assertion `dest != __null' failed.
Aborted (core dumped)
使用此代码时:
//decryption
AES::Decryption aesDecryption(key, AES::DEFAULT_KEYLENGTH);
CBC_Mode_ExternalCipher::Decryption cbcDecryption( aesDecryption, iv );
StreamTransformationFilter stfDecryptor(
cbcDecryption,
new StringSink( recoveredtext ),
BlockPaddingSchemeDef::NO_PADDING
);
stfDecryptor.Put( reinterpret_cast<const unsigned char*>( ciphertext.c_str() ), ciphertext.size() );
stfDecryptor.MessageEnd();
它可以工作,但输出不是有效的字符序列。
我安装了该库:
sudo apt-get install libcrypto++-dev libcrypto++-doc libcrypto++-utils
我编译它:
g++ -o AESCBC128 AESCBC128.cpp -lcryptopp
我找不到问题所在。
先谢谢您的帮助。
输入样本:
140b41b22a29beb4061bda66b6747e14
4ca00ff4c898d61e1edbf1800618fb2828a226d160dad07883d04e008a7897ee2e4b7465d5290d0c0e6c6822236e1daafb94ffe0c5da05d9476be028ad7c1d81
我不知道输出示例,因为这是一个练习,我的目标是发现秘密消息。
测试输入和转换为字节数组:
out << "KEY:\n" << hex_key << endl;
for(int i = 0; i < AES::DEFAULT_KEYLENGTH; i++) {
out << setfill('0') << setw(2) << hex << (int)key[i];
}
out << endl << "Received message:\n" << hex_ct << endl;
out << "IV:\n";
for(int i = 0; i < AES::BLOCKSIZE; i++) {
out << setfill('0') << setw(2) << hex << (int)iv[i];
}
out << endl << "CT:\n" << ciphertext << endl;
Result:
KEY:
140b41b22a29beb4061bda66b6747e14
140b41b22a29beb4061bda66b6747e14
Received message:
4ca00ff4c898d61e1edbf1800618fb2828a226d160dad07883d04e008a7897ee2e4b7465d5290d0c0e6c6822236e1daafb94ffe0c5da05d9476be028ad7c1d81
IV:
4ca00ff4c898d61e1edbf1800618fb28
CT:
28a226d160dad07883d04e008a7897ee2e4b7465d5290d0c0e6c6822236e1daafb94ffe0c5da05d9476be028ad7c1d81
他们正如预期的那样。