Cipher/Decipher Testing (with Xor)

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Socoder -> Blitz -> Cipher/Decipher Testing (with Xor)
Fri, 03 Apr 2020, 05:32
Dan	Cipher/Decipher Testing (with Xor) Hi, i have found this code, over on the german blitzbasic forum, for simple de/ciphering of the text, using xor. I made two functions of it and added arrow keys control, to display the results. Left + right move by 1, up + down move the number by 10. Basically, the ciphering is working, but the numbers 0 and 32 are to be avoided, because 0 returns the same text, and 32 returns it as switched upper/lower case letters. ; Einfache VerschlÃ¼sselung ; 2004, by Triton ;Test by Dan - 2020 (testing xor numbers 0-255) - look at the # 0 and 32 ! ;1st line is the text ;2nd line is the xored text ;3rd line is the xor on the xored text (should be the same as the 1st line 1) Graphics 900,80,32,2 Graphics 900,40,32,3 txt$ = "Dies ist ein Testtext! The quick brown fox jumps over the lazy dog is an English-language pangram :-D ÃœÃ–AÃ¼Ã¶Ã¤" Global zahl = 01 MSG$="Press Left/Right/Up/Down Arrow key \| using Xor(" Font=LoadFont("Blitz",12,False,False,False) SetFont Font T=M() Repeat Cls AppTitle(MSG$+zahl+")") txt2$=Cipher(txt$) txt3$=Decipher(txt2$) Color $ff,$FF,0 Text 0,0,Txt$ ;Original text Text 0,27,txt3$ ;double xor-ed (txt$) If txt<>txt2 Then Color 0,$ff,$FF If zahl=32 Or zahl=0 Then Color $ff,0,0 Text 0,14,txt2$ ;Xored txt2 - or ciphered txt k=KeyDown(205)-KeyDown(203) ;Left Right l=KeyDown(200)-KeyDown(208) ;Up Down If K=1 And M()-t>220 Then zahl=(zahl+(zahl<255)) : t=M() If k=-1 And M()-t>220 Then zahl=(zahl-(zahl>0)) : t=M() If l=1 And M()-t>220 Then zahl=(zahl+(10(zahl<(255-10)))) : t=M() If l=-1 And M()-t>220 Then zahl=(zahl-(10(zahl>(0+10) ))) : t=M() Delay 25 Until KeyDown(1) Function M() Return MilliSecs() End Function Function Cipher$(txt$) ;VerschlÃ¼sseln in txt2$ Local txt2$,oft,zeichen$ For oft = 1 To Len(txt$) zeichen$ = Mid$(txt$,oft,1) txt2$ = txt2$+Chr$(Asc(zeichen$) Xor zahl) Next Return txt2$ End Function Function Decipher$(txt$) ;EntschlÃ¼sseln in txt3$ Local txt2$,oft, zeichen$ For oft = 1 To Len(txt$) zeichen$ = Mid$(txt$,oft,1) txt2$ = txt2$+Chr$(Asc(zeichen$) Xor zahl) Next Return txt2$ End Function --v
Fri, 03 Apr 2020, 06:24
Jayenkai	Increase complexity with a Keyword. Keyword$="This Is My Encryption Key" And then within your loop, instead of always using the same zahl value, grab zahl as the ascii value of the wrapped character in the keyword. For oft = 1 To Len(txt$) zeichen$ = Mid$(txt$,oft,1) zahl=Asc(Mid$(Keyword$,oft mod Len(Keyword$),1)) if zahl==0 or zahl==32 then zahl=69 txt2$ = txt2$+Chr$(Asc(zeichen$) Xor zahl) Next --v (apologies if that code's a bit mangled.. did that in the browser!) -=-=- ''Load, Next List!''
Sat, 04 Apr 2020, 00:21
Dan	Yeah, they had a complex encryption method too, but i was curious to see how the each string is xor-ed, by a single number, hence the demonstration code.
Sat, 04 Apr 2020, 12:28
Krakatomato	XOR encryption is pretty pointless - it's very easily broken and seriously insecure. If you need to encrypt something then look at stronger methods. Otherwise, don't bother. If your goal is just to hide information from the "casual user/gamer" then there's far better ways of doing this. Not saying for the sake of it - info sec is part of my day job for large corps (and is seriously tedious and boring).