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Hill cipher, CBC, and One time pad

Name: Anonymous 2006-05-09 11:04

I'm going to make this post, then post it again in the replies as a Hill encoded (with CBC) message and a One-time Pad encoded message.  In both cases, the key is goback2b, something I thought might be a bit fitting.  I wrote this to allow a fairly secure encryption method that could be used on the internet.  Most formats work with files directly.   However, on message boards and such, we have to work with characters.  A lot of ASCII values are really odd characters, which may or may not display differently on different machines.  I chose to work with just the 71 most common characters.  This means you can copy and paste it around without messing everything up.  Could be interested to try here, to see what we can do.  The Hill cipher is veunerable to a known-plaintext attack, but requires n-squared pairs with the same key.  It's doubtful anybody here would be using the same key more than a few hundred times, though this could be a problem if the messages are all short.  Anyways, I'll post the code later, if desired.  For now, what could this be used for?

Name: Anonymous 2006-05-09 11:06

(AnmD7CFPGH2r0vUZxgZruHArW95Mw)jm(HlMviWhz1H evW1H EGgUjsImNO70WUv,HHsJDV.f(R7AXsGsQ89FKzurDvfZkn,E4oc2,kN)18wc)USf,sLGUTnOtEj2nD'3gZmbzbWT6c4WGJ)bH6BentIHp,f?M5,NJ!ucKzBfHGPcSzYgpta6EX0U7VYsE0kitE2 PGcFaYFqeVcyK0YBl,4MqqfhkDzADc,uPsOmH4.qHO5vw450389-fE4W19MKN,NAJ'KWes'7NiRXrtVngL)lZcW5mGMzngNIyle7xVIh10O3QiAPPSO!,gQVE ?2CPy8P4rS8qkdcodYhMtD7bee7IXGG1,EVNS.iXFFNmhj4CqN'8HOgyWAqKgn!OabfSTzTB!,LZf615wb,b(RoMF16mXLwPlXgBepfzV.-NWOOIFbH(MGcYDj(QXt9AuntcILibS3pnpsZoC0Zk?!?5 hR,Q '2rGvKKDgnV(B,!8qwBI5wvCDACd5?Q.BuRJ-m(6JRl-oI4leMrd'YG,d70(97xWvc9ohI0JZA7SDuD0ZDbN7LhTEoqJ!qTWc1FmJF4WB6,lERezwjY0!oJ9Jzo0u0rZ1KwUXBdbvzF-pbnelcHJh'Llk)XcSnR,u,PxmF.Y5VESTE4U1pseGIUP1mVtIfPlSKt,YDMl1IGw0xlCeH.xFYmR.tnKNJlYZJF08I9IYbXKVvjXsN6jU.TmZeAV-GmoyCbVS-u)2h4(lWz.S?YlSToCh6EuWh cm3'AMjpC,O8p-m(qWY!fBOl!-OraeX(Ta-G5T2B17nyeKl.vqgWZkhFCNKkzQ!7E(RLSwmWV67oD-lqko97,iFyw0pLprEKsQPm!TKKDXKJIUbH!LngbZ53Wasm 1dY.w7mdRy2PiGRht!fmQbCYmqhK yDvb-qrMN(o8eXkD'fvw)VogLSQxBc-gBmrtJ6BGqaCzSYqQ)eOWsYKfW'-(ipv8ZbWjBjOxUYZDoWR9yGc)4K(W9MFA2P.Y7ZsQA02hX(LraA10hm(?qd2EqdtBh0KshRZD0bvW1hVgA0PEd?qpenI

Name: Anonymous 2006-05-09 11:06

zlFaAQkGEoMGcOcDCoM0CU2IMYMScVj8LoIGMV2BRo495KpbGTbLBG2KCVEA9U24Qo4auKnEgKG5IFg7gmPANJ2os.aaGGuL9M8a5Pfb9o,F9gvBKKb,5F28LIH69F2FCYL3AG?bg)Ga6QvAgI4K9U!bRN8aEG,bGYb9IDc6Iq5ScUqFCZAAHI2ugZAGOIjMgSB9BV25Co4a6KvbDOMLCPiUgouaQTqMCoM0CU2MMo4DFQyb9o93CTnRgY85OTgbCT6JSRvBMTbE9VjHBoM05V26MaE6cDgbSY86cQpbRN8aCPv8PT8LVk2yMYMa0QtF9ZLaQQtDgcBLBkhBJKLa8Kt8AZEQVk2byUP7PGtTgUGaGGuL9M8a6QcKBYb3HF2LSIAScYgbFGO7cVqbUUKCcYkMFo605Tc6RKKKVk2mgRHLcQhbr9otvkx4Ja8KcCt8gX83FN,bMJ7a7JcK9IM7LU!bUNB5Bko4WoHJcOcRgTHLcFkLNR4QcFk9DKK7HVnRgUGa8Kh9CX8FNko4ANBF9U?bg)b5BQu8gZHaQQtDgcBLBklNQZbLBG2ihoFGMV26MSFGHkeA9X45NGtLZob-BKubKK4FMk,HSo63HkeHNeb3HF2I9YM7cKvb9XHMHF2PGZAGOV2FCYLAHI28TKKQNJkGEoNHVk2oMaE6cDgbGTM7LGuMCJbLIkvKWoA7LG!bRUbK9G2PFGMaQG269Tb6Id2b2N8auKnEgIBHBGtbGYbN9Wp8PG5D9kvHgGbCHQyGcVE3CPv8VZb3NVc6Igb4OV2KCWNALGubLkLIOCt8BoI3CTubUOM0cVj8gY4E9km8WhbavV)LgJHM6VhNJo4FSDq7WoA7LG2PMaE6cDgbSYBFAkvACoL3GG2DCebEITgbRN4FcC29Ccb0OPfKCJbLCOgLYoM0IWiAgZAAMkeHSR7a6G24gVKG6NgFgO9aNJgbKKLK5IgLgGK7cCnEgYAGLV?bgzGQQC,LYouXFN2IMYMaNJgbAU77cNcMCXTaCH27CYBJ9F?bg-HJcPqPYoP05V26MaE6cVjBQo57cWu8Bo9GLf

Name: Anonymous 2006-05-09 12:16 (sage)

base64 motherfucker, do you know it?

Name: Anonymous 2006-05-09 12:16

nope, explain please

Name: Anonymous 2006-05-09 12:20

Base64 doesn't use a key, it just jumbles your letters.  You may as well just write everything backwards.  It would take zero effort to decrypt.  Fails.

Name: Anonymous 2006-05-09 13:02 (sage)

>>6
I don't mean as an alternative to encryption, but instead of this 71 character method. For encryption, why not use AES or something?

Name: Anonymous 2006-05-09 13:45

I am going to encode using RSA bitches. try to decrypt that!

Name: Anonymous 2006-05-09 13:49

>>7
Because AES would give you a lot of screwy characters.  What happens when you end up with a carriage return?  Or a new line?  How do different browsers display such characters?  How do they copy them?  And on a practical level, why bother using AES when a hill-cipher works pretty much just as well?  I don't know of any AES encryption software out there that will work with text instead of packets or files.

Name: Anonymous 2006-05-09 14:08 (sage)

>>9
No, dumbass, you're still confusing encryption and encoding. You get 'screwy characters' if you encode the output from encryption (AES or any other useful kind) directly as bytes, you get copyable text if you use base64.

Name: Anonymous 2006-05-09 14:26

>>8
I've decrypted an RSA system once because of failure to use primes far apart from eachother, despite being large.

Name: Anonymous 2006-05-09 14:37

>>10
I think you're confusing encryption and encoding.  Base 64 doesn't offer any kind of security.  Anybody who knows what it is can decode it.  A hill cipher provides a key; only if you have the key can you decrypt the ciphertext and get a useable plaintext again.  Only about half the symbols in the ASCII range are clearly defined.  The rest, though also defined, can vary in implimentation.  How does it show up on your screen?  Will it stay the same between your word processor and your web browser?  What about somebody elses?

Name: Anonymous 2006-05-09 15:56

>>11
http://arxiv.org/PS_cache/cs/pdf/0402/0402052.pdf

here is a method to crack RSA with small secret exponents using continued fractions.

Name: Anonymous 2006-05-09 17:01 (sage)

>>12
RETARD.
You encrypt the text first. Using AES or any good encryption algorithm.
THEN you convert THE ALREADY ENCRYPTED BYTES to base64 to make it copypastable.

Name: Anonymous 2006-05-09 17:26

>>14
Fair enough.  But the point is to make a readable ciphertext.  Converting with Base64 is inefficient from a size point of view.  If you're going to have to add an extra step at the end, it defeats the purpose.  Unless you really need AES-level incryption for your self-insertion furry-fanfics.  (I don't.)

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