(Blow)Fish Encryption

[sc4ry]

Hello Everybody,

i want to decrypt some text from mIRC, which uses FiSH (http://fish.secure.la/). FiSH is using the Blowfish-Algo. I tried the blowfish.au3 from here (http://www.autoitscript.com/forum/index.php?showtopic=44581&st=0&p=332160&#entry332160), but it seems not so easy to use the key and the text to decrypt.

I receive the following code, which is crypted with password "1234" (without "") -> +OK XyYxV1HYaF.1

Now i want to find the way, to decrypt this msg with the key to receive -> Blubb

I think there must be 2 ways: 1. Using blowfish.au3; 2. Using FiSH.dll

At this time, i have no idea, how to use the blowfish.au3 for that, but maybe, if i/we understand, how Fish works?

What i find in the mrc, is the follwing (but because i´m a dll and decryption noob, this does not really helps me ;-))

int decrypt_string(char *key, char *str, char *dest, int len);

int encrypt_string(char *key, char *str, char *dest, int len);

$dll(%FiSH_dll,DH1024_comp, %FiSH.prv_key $2)

If i take a look in the dll (with dependency walker), i also find the functions FiSH_decrypt_msg und FiSH_encrypt_msg. But both together does not show me, how to use it.

could anybody help me?

thanks very much.

[PsaltyDS]

I receive the following code, which is crypted with password "1234" (without "") -> +OK XyYxV1HYaF.1

Now i want to find the way, to decrypt this msg with the key to receive -> Blubb

That sounds like you want an asymmetric algorithm. Blowfish is a symmetric algorithm, which means the same key must be used to decrypt that was used to encrypt. You want to encrypt with one key ("1234") and decrypt with a different one ("Blubb"), sort of like with RSA.

I don't know anything about "FiSH". Maybe it puts an asymmetric wrapper of some kind around a Blowfish encrypted block of data. You would have to take that up with them.

[DoubleMcLovin]

That sounds like you want an asymmetric algorithm. Blowfish is a symmetric algorithm, which means the same key must be used to decrypt that was used to encrypt. You want to encrypt with one key ("1234") and decrypt with a different one ("Blubb"), sort of like with RSA.

I don't know how to help with this problem, but after reading the question, he does not want to decrypt with a different key, "Blubb" id the decrypted text. 1234 remains the key throughout.

[PsaltyDS]

I don't know how to help with this problem, but after reading the question, he does not want to decrypt with a different key, "Blubb" id the decrypted text. 1234 remains the key throughout.

I see what you mean. I may have misunderstood the question.

As for the FiSH DLL, is there documentation available for it?

Edited April 14, 2010 by PsaltyDS

[evilertoaster]

Blowfish keys should be a multiple of 8, otherwise different implementations might pad them differently (and give you different results). Here's an exmaple for enc/dec for the AutoIt version:

#include "Blowfish.au3"
$text="Blubb"
$key="12345678"
$cipher=Blowfish($key,$text,0)
MsgBox(0,"This encrypted text is",$cipher)
$decrypted=Blowfish($key,$cipher,1)
MsgBox(0,"There and back agian:",$decrypted)

This matches a 2nd implementations results (http://webnet77.com/cgi-bin/helpers/blowfish.pl) so I'd assume it's correct. Now you just to verify the encrypted text given to you by the FiSH algo...

[PsaltyDS]

Nice catch. I was comparing to this site: http://www.oclib.com/library/com/oclib/javascript/security/encryption/blowfish/20070210/demo.html, and it came up different from SkinnyWhiteGuy's function every time. Using the one you found, it matches (after conversion with "StringToBinary($cipher)").

[evilertoaster]

http://www.oclib.com/library/com/oclib/javascript/security/encryption/blowfish/20070210/demo.html is most likely wrong or it expects input differently, or has an implementation quirk (maybe a different block mode). Skinny's and http://webnet77.com/cgi-bin/helpers/blowfish.pl match the values expected by the text vectors- http://www.schneier.com/code/vectors.txt Edited April 14, 2010 by evilertoaster

[sc4ry]

Hey,

thank you for your help. Cause i´m german, i don´t understand all what you wrote. sorry for that ;-)

using the blowfish.au3 isn´t that hard, but the result is not that, what i want or expect. i don´t know, what the fish.dll really does ... but i want to build that back. and the only thing i know already is, that it also uses blowfish ... but in what way?

maybe i have to use directly the dll and not the blowfish.au3 ... but how?

something i know found is, how the call should be done:

FiSH_encrypt_msg(HWND mWnd, HWND aWnd, char *theData, char *params, BOOL show, BOOL nopause)

know i have to do this in autoit (with nearly no dll-expirience). if anyone have a tip ... please let me know =)

[sc4ry]

and a BIG, GREAT THANKS goes tooooo ... BugFix =)

He did the following:

Func _FiSH_encrypt_msg($mWnd, $aWnd, $sData, $show, $nopause)     Local $tData = DllStructCreate('char[900]')     DllStructSetData($tData, 1, $sData)     Local $tParams = DllStructCreate('char[900]')     Local $ret = DllCall('Fish.dll', 'int', 'FiSH_encrypt_msg', 'hwnd', $mWnd, 'hwnd', $aWnd, 'ptr', DllStructGetPtr($tData), _                 'ptr', DllStructGetPtr($tParams), 'BOOLEAN', $show, 'BOOLEAN', $nopause)     If @error Then Return SetError(@error,0,-1)     Switch $ret[0]         Case 0, 1             Return $ret[0]         Case 2             Local $aOut[2] = [DllStructGetData($tData,1), DllStructGetData($tParams,1)]             Return $aOut         Case 3             Return DllStructGetData($tData,1)     EndSwitch EndFunc

which works fine with following settings:

$mWnd = WinGetHandle("[Class:SciTEWindow]") $aWnd = ControlGetHandle("[Class:SciTEWindow]", "", "Scintilla2") $sData = "1234 Blubb" $show = True $nopause = True