问题描述
在输入文件中，我有：
在第一行一个以十六进制编码，长度为16字节的密钥;
在第二行加密消息（AES128在CBC模式下，随机添加一个加密消息）。
b
$ b
这是我如何解密：
＃include< iostream>
使用命名空间std;
#include< fstream>
#include< string.h>
#include< cryptopp / aes.h>
#include< cryptopp / modes.h>
#include< cryptopp / filters.h>
使用命名空间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 =，restoredtext =; （int i = 0; i< hex_key.size（）; i + = 2）{
key [i / 2] =（char）strtol（（hex_key.substr i，2））。c_str（），0,16）;
}
//然后我将文本从
中分开（int i = 0; i< AES :: BLOCKSIZE * 2; i + = 2）{
iv [i / 2] =（char）strtol（（hex_ct.substr（i，2））。c_str（），0,16）; （int i = AES :: BLOCKSIZE * 2; i< hex_ct.size（）; i ++）{
ciphertext.push_back（hex_ct [i]）
}
;
}
//解密
CBC_Mode< AES> ::解密d
d.SetKeyWithIV（key，AES :: DEFAULT_KEYLENGTH，iv）;
StringSink sink（deletedtext）;
StreamTransformationFilter stf（
d，
& sink
）;
StringSource ss（
ciphertext，
true，
& stf
）;
out<< recoveredtext;
return 0;
}
我在。
我也尝试过，而且它有效，但是没有用我的替换密钥和密文。
嗯，使用上面的代码我有这个输出：
AES128CBC：/usr/local/include/cryptopp/misc.h:304：void CryptoPP :: memcpy_s（void *， size_t，const void *，size_t）：断言`dest！= __null'失败。
中止（核心转储）
使用此代码时：
//解密
AES ::解密aesDecryption（key，AES :: DEFAULT_KEYLENGTH）;
CBC_Mode_ExternalCipher ::解密cbcDecryption（aesDecryption，iv）;
StreamTransformationFilter stfDecryptor（
cbcDecryption，
new StringSink（deletedtext），
BlockPaddingSchemeDef :: NO_PADDING
）;
stfDecryptor.Put（reinterpret_cast< const unsigned char *>（ciphertext.c_str（）），ciphertext.size（））;
stfDecryptor.MessageEnd（）;
它的工作原理，但输出不是有效的字符序列。
我安装了lib：
sudo apt-get install libcrypto ++ -dev libcrypto ++ - doc libcrypto ++ - utils
我编译它：
g ++ -o AESCBC128 AESCBC128.cpp -lcryptopp
我找不到什么问题。
提前感谢帮助。
输入示例：
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：\\\
<< hex_key<< ENDL; （int i = 0; i< AES :: DEFAULT_KEYLENGTH; i ++）
{
out< setfill（'0'）<< setw（2）< hex< （INT）键[I];
}
out<< endl< Received message：\\\
<< hex_ct<< ENDL;
out<< IV：\\\
; （int i = 0; i< AES :: BLOCKSIZE; i ++）
{
out< setfill（'0'）<< setw（2）< hex< （int）的四[I];
}
out<< endl< CT：\\\
<<密文<< ENDL;
结果：
code> KEY：
140b41b22a29beb4061bda66b6747e14
140b41b22a29beb4061bda66b6747e14
接收消息：
4ca00ff4c898d61e1edbf1800618fb2828a226d160dad07883d04e008a7897ee2e4b7465d5290d0c0e6c6822236e1daafb94ffe0c5da05d9476be028ad7c1d81
IV：
4ca00ff4c898d61e1edbf1800618fb28
CT：
28a226d160dad07883d04e008a7897ee2e4b7465d5290d0c0e6c6822236e1daafb94ffe0c5da05d9476be028ad7c1d81
正如预期的那样。
可能的原因是填补错误不是填充，而是解密是错误的，参数的提供方式可能不正确。
我在提供的KEY，IV和CT上对解密进行了编码。结果具有0x08的8个字节的PKCS＃7填充。
（正确删除iv）
解密删除填充：
或文字：
解密填充完整（注意填充的尾随8个字符）：
输出大部分是ASCII，有一些例外，如第3个字节0xfc。
由于填充是正确的，我相信这是加密的真实数据。
对于过于好奇的是我的测试代码：
NSData * key = [Utilities dataFro mHexString：@ 140b41b22a29beb4061bda66b6747e14];
NSData * iv = [实用程序dataFromHexString：@4ca00ff4c898d61e1edbf1800618fb28];
NSData * dataIn = [实用程序dataFromHexString：@28a226d160dad07883d04e008a7897ee2e4b7465d5290d0c0e6c6822236e1daafb94ffe0c5da05d9476be028ad7c1d81];
size_t cryptBytes = 0;
NSMutableData * dataOut = [NSMutableData dataWithLength：dataIn.length + kCCBlockSizeAES128];
CCCrypt（kCCDecrypt，
kCCAlgorithmAES，
kCCOptionPKCS7Padding，
key.bytes，key.length，
iv.bytes，
dataIn。 bytes，dataIn.length，
dataOut.mutableBytes，dataOut.length，
& cryptBytes）;
dataOut.length = cryptBytes;
NSLog（@dataOut：％@，dataOut）;
NSLog（@dataOut：％@，[[NSString alloc] initWithData：dataOut encoding：NSUTF8StringEncoding]）;
In the input file I have:
on the first line a key which is encoded in hex and with length of 16 bytes;
on the second line encrypted message ( AES128 in CBC mode , with a random iv prepended to the encrypted message).
This is how I tried to decrypt:
#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;
}
I used this implementation following the Wiki.
I also tried with this and it worked, but not replacing key and ciphertext with my.
Well, using the code above I have this output:
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)
While using this code:
//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();
It works but the output isn't a valid sequence of characters.
I installed the lib with:
sudo apt-get install libcrypto++-dev libcrypto++-doc libcrypto++-utils
and I compiled it with:
g++ -o AESCBC128 AESCBC128.cpp -lcryptopp
I can't find what's wrong.
Thanks in advance for the help.
Sample of input:
140b41b22a29beb4061bda66b6747e14
4ca00ff4c898d61e1edbf1800618fb2828a226d160dad07883d04e008a7897ee2e4b7465d5290d0c0e6c6822236e1daafb94ffe0c5da05d9476be028ad7c1d81
I don't know a sample of output because this is an exercise and my goal is to discover the secret message.
Test on the inputs and on conversion to byte arrays:
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
They are as expected.
A probable reason you are getting a padding error is not the padding but that the decryption is wrong, the way the parameters are supplied is probably incorrect.
I coded up decryption on the supplied KEY, IV and CT. The result has PKCS#7 padding of 8 bytes of 0x08.
(correct to remove iv)
Decryption with padding removed:
or in text:
Decryption with padding intact (note the trailing 8 characters of padding):
The output is mostly ASCII with a few exceptions such as the 3rd byte 0xfc.
Because the padding is correct I believe this is the true data that was encrypted.
For the overly curious here is my test code:
NSData *key = [Utilities dataFromHexString:@"140b41b22a29beb4061bda66b6747e14"];
NSData *iv = [Utilities dataFromHexString:@"4ca00ff4c898d61e1edbf1800618fb28"];
NSData *dataIn = [Utilities dataFromHexString:@"28a226d160dad07883d04e008a7897ee2e4b7465d5290d0c0e6c6822236e1daafb94ffe0c5da05d9476be028ad7c1d81"];
size_t cryptBytes = 0;
NSMutableData *dataOut = [NSMutableData dataWithLength:dataIn.length + kCCBlockSizeAES128];
CCCrypt(kCCDecrypt,
kCCAlgorithmAES,
kCCOptionPKCS7Padding,
key.bytes, key.length,
iv.bytes,
dataIn.bytes, dataIn.length,
dataOut.mutableBytes, dataOut.length,
&cryptBytes);
dataOut.length = cryptBytes;
NSLog(@"dataOut: %@", dataOut);
NSLog(@"dataOut: %@", [[NSString alloc] initWithData:dataOut encoding:NSUTF8StringEncoding]);
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