Article View: comp.lang.pascal.misc
Article #155Re: *******REVERSE ASCII**********
From: Rune Moberg
Date: Mon, 30 Sep 1996 00:00
Date: Mon, 30 Sep 1996 00:00
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1740 bytes
>>I know of a college who reversed ASCII values for an encryption >>program. DOES ANYONE KNOW THE CODE TO DO THIS. Hmm... "Reversed ASCII" That sounds like XOR'ing to me. If you take a value and XOR it with something else, then you can repeat the operation and get back the original value. result := ord(somechar) XOR $FF; //also a bit toggle now, if you do: result := result XOR $FF; then result will hold the decrypted value of somechar. XOR is explained in almost every text book, but this is basically what's going on: value XOR value = result ------------------------ 0 | 0 = 0 0 | 1 = 1 1 | 0 = 1 1 | 1 = 0 And that's what an eXclusive OR does... -- =\ homepage @ http://www.qsd.no/staff/rune *=- R.Moberg, CD-Player Pro info @ http://home.sn.no/home/mobergru/ =/ my own webserver @ http://pumba.qsd.no
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X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 10261c,38608a28b5863775 X-Google-Attributes: gid10261c,public X-Google-Thread: 11185f,8746d3f6e7cf3444 X-Google-Attributes: gid11185f,public X-Google-Thread: 111659,8746d3f6e7cf3444 X-Google-Attributes: gid111659,public X-Google-Thread: 102601,8746d3f6e7cf3444 X-Google-Attributes: gid102601,public From: mobergru@oslonett.no (Rune Moberg) Subject: Re: *******REVERSE ASCII********** Date: 1996/09/30 Message-ID: <0ZvTy0JfF2bd089yn@oslonett.no> X-Deja-AN: 186157070 sender: mobergru@sn.no references: <1996Sep27.160013.6675@arl.mil> content-type: text/plain; charset=ISO-8859-1 organization: CD-Player Pro author! mime-version: 1.0 newsgroups: comp.lang.pascal.misc,comp.lang.pascal.borland,ctdl.lang.pascal,osu.pascal