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JoeCoder
Joined: 29 Oct 2005
Posts: 294
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 Posted: Wed Sep 24, 2008 9:48 pm Post subject: Comparing results with PHP's mcrypt. |
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First, I'm very glad to see that D is getting a powerful encryption library such as this--much thanks.
I'm working on encrypting some data in D (Blowfish/CBC/null padding) and decrypting it in PHP. My code works about 9 times out of 10, but I get garbage every now and then. I broke my test down to the following basic cases. D1.0 and PHP 5.2x with the mcrypt extension:
| Code: | import dcrypt.crypto.ciphers.Blowfish;
import dcrypt.crypto.modes.CBC;
import dcrypt.crypto.padding.NullByte;
import dcrypt.crypto.ManagedBlockCipher;
void main() {
ubyte[] key = cast(ubyte[])"somethin";
ubyte[] iv = cast(ubyte[])"\0\0\0\0\0\0\0\0";
ubyte[] plaintext = cast(ubyte[])"12345678";
ManagedBlockCipher cipher = new ManagedBlockCipher(new CBC(new Blowfish), new NullByte);
ParametersWithIV params = new ParametersWithIV(new SymmetricKey(key), iv);
cipher.init(true, params);
ubyte[] ciphertext = new ubyte[cipher.finishOutputSize(plaintext.length)];
uint amount;
// Let's do some encrypting
amount = cipher.update(plaintext, ciphertext);
cipher.finish(ciphertext[amount..ciphertext.length]);
// Show you the goods
foreach (ubyte i; ciphertext)
printf("%02x", i);
} |
Outputs: e3555bf67269c266b7dfdd542653c432
| Code: | <?php
$key = 'somethin';
$iv = "\0\0\0\0\0\0\0\0";
$plaintext = '12345678';
$encrypted = mcrypt_encrypt(MCRYPT_BLOWFISH, $key, $plaintext, MCRYPT_MODE_CBC, $iv);
for ($i=0; $i < strlen($encrypted); $i++)
print dechex(ord($encrypted[$i]));
?> |
Outputs: e3555bf67269c266
The D output is very similar to the PHP output but is twice as many bytes. I can of course trim it, but I'd rather know if anyone actually knows what's going on.
Am I missing anything obvious? Thank in advance. |
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reikon
Joined: 31 Jul 2008
Posts: 7
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| Posted: Tue Jan 20, 2009 6:31 pm Post subject: |
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Wow! I didn't realize dcrypt had a forum. Much apologies for the very slow response!
The additional block is added as a result of using padding. An extra block is always added when padding is used and data falls on a block boundary (that is, the data is a multiple of the block size of the cipher).
To quote Wikipedia:
| Quote: |
If the input happens to fill up an entire block, another block is added to accommodate the padding; otherwise, the end of the input plaintext might be misinterpreted as padding.
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Thanks for using dcrypt, and again, I apologize for the slow response! |
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