Testing the CFB Mode I've noticed that it gives me some strange
results. I tested the same mode with the same IV and Key in a PHP and
Python script:
//----------------------------------
//init key & iv
$key = "xxxxxxxxxxxxxxxxxxxxxxxx";
$iv = "xxxxxxxxxxxxxxxx";
//print key
echo ('key: ' . $key . "\n");
echo ('iv: ' . $iv . "\n");
//print iv
echo ('----------------------------------------' . "\n");
//original
$original = 'hello';
echo ('original: ' . $original . "\n");
//encode
$encoded = mcrypt_cfb(MCRYPT_RIJNDAEL_128, $key, $original,
MCRYPT_ENCRYPT, $iv);
echo ('encoded (hex): ' . str2hex($encoded) . "\n");
//decode
$decoded = mcrypt_cfb(MCRYPT_RIJNDAEL_128, $key, $encoded,
MCRYPT_DECRYPT, $iv);
echo ('decoded: ' . $decoded . "\n");
//----------------------------------
Both scripts returned the same ciphertext. However, after testing
Crypto++ I got a different result. Only the first hex number was
right. This ist the code:
//----------------------------------
const unsigned int keyLength = 24;
byte key[24], iv[keyLength];
memset(key, 0x78, keyLength);
memset(iv, 0x78, AES::BLOCKSIZE);
string plaintext = "hello";
string ciphertext;
string decryptedtext;
cout << "Plain Text (" << plaintext.size() << " bytes)" <<
endl
<< plaintext << endl << endl;
AES::Encryption aesEncryption(key, 24);
CFB_Mode_ExternalCipher::Encryption
cfbEncryption(aesEncryption, iv);
StreamTransformationFilter stfEncryptor(cfbEncryption, new
StringSink(ciphertext),
StreamTransformationFilter::NO_PADDING);
stfEncryptor.Put(reinterpret_cast<const unsigned
char*>(plaintext.c_str()), plaintext.length() + 1);
stfEncryptor.MessageEnd();
cout << "Cipher Text (" << ciphertext.size() << " bytes)\n";
for(size_t i = 0; i < ciphertext.size(); i++)
cout << "0x" << hex << (0xFF &
static_cast<byte>(ciphertext[i])) << " ";
//----------------------------------
Probably I did something wrong. Can somebody offer any help? :-)
--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the "Crypto++ Users"
Google Group.
To unsubscribe, send an email to [EMAIL PROTECTED]
More information about Crypto++ and this group is available at
http://www.cryptopp.com.
-~----------~----~----~----~------~----~------~--~---
