Decryption/Encryption Tutorials and Basics

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Decryption/Encryption Tutorials and Basics

Post by k0z1 on Wed Jun 10, 2009 11:53 am
([msg=25195]see Decryption/Encryption Tutorials and Basics[/msg])

Was googling encryption/decryption trying to find some tutorials to get started off on. I can't seem to find any and was wondering if anyone knew some helpful sites I could visit to get a basic understanding of how encryption works. Thank You.
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Re: Decryption/Encryption Tutorials and Basics

Post by TrebleTatoo on Wed Jun 10, 2009 1:04 pm
([msg=25197]see Re: Decryption/Encryption Tutorials and Basics[/msg])

I'm not sure of any reliable sites, but i just finished reading a book called "The Code Book"
Its basically everything there is to know about encryption,decryption and how its played out through history, i didn't know crap about encryption until i read the book.
Its found in most public libraries.
Hope this helps :)
--TT
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Re: Decryption/Encryption Tutorials and Basics

Post by sandsphinx on Wed Jun 10, 2009 1:52 pm
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I am thinking of making a small website with little tiny tutorials that include flash, powerpoints, yknow, a bit like w3schools, but with a bit more kiddie feel to it. Its going to be much simpler, and i love the way w3schools have the "try it yourself" demos, i like that idea. I was thinking that the website has way too much text! The website will consist of:
Tutorials; Flash, Powerpoints, Games,
Tests; A test at the end of the Tutorial.
Fact Sheets; entites, encryptions, codes, copy and paste panel...
Submit Form; so you can submit your own tutorial... will be approved firstly
Members; maybe, but im not that good with databases and so on....


Do you think when people get a problem such as the one you are experiencing right now, that this website will be good, it won't be huge, and it will be on a free domain server, but i think the potential is massive...

What do you think?
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Re: Decryption/Encryption Tutorials and Basics

Post by k0z1 on Wed Jun 10, 2009 2:30 pm
([msg=25206]see Re: Decryption/Encryption Tutorials and Basics[/msg])

@TrebleTatoo: I looked on my local library online catalog system and the book "The Code Book" is available for checkout. The description of it seems pretty interesting and I feel that this is what I am looking forward to in terms of gaining a basic understanding of encryption.

@Sandsphinx: Your website idea sounds like something I would greatly love to study right now. I couldn't find anything of that nature through google. W3schools hits the nail on the head with HTML. Would love to see more sites like that for a broader range of information. Best of luck to you and your endeavours.
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Re: Decryption/Encryption Tutorials and Basics

Post by Nines on Wed Jun 10, 2009 6:20 pm
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k0z1 wrote:Was googling encryption/decryption trying to find some tutorials to get started off on. I can't seem to find any and was wondering if anyone knew some helpful sites I could visit to get a basic understanding of how encryption works. Thank You.


http://www.hoozi.com/Articles/AESEncryption.htm

I was reading this the other day.. It breaks down the cipher so that you can understand how it works. I don't know how well you'll follow the documentation as it's not really aimed at beginners in cryptography but I enjoyed reading through it so you might learn a little :)

------------ Mini tutorial: ------------

It might help if you went through examples of basic XOR (exclusive-or) encryption using a one-time-pad and tried to write your own implementation. It teaches you the basics behind symmetrical operations like:

[ciphertext-character] = [plaintext-character] XOR [key-character]

In this example let's say the plaintext is "money" and the key is "68131". (I'm using numbers because the XOR operation would yield results outside of printable characters, but in reality you can use anything) I'll use ^ in the example below.. This means a bitwise XOR operation (not an exponent!)

Ascii values:

'm' = 109
'o' = 111
'n' = 110
'e' = 101
'y' = 121


'6' = 54
'8'= 56
'1' = 49
'3' = 51
'1' = 49


So:

109 ^ 54 = 91
111 ^ 56 = 87
110 ^ 49 = 95
101 ^ 51 = 86
121 ^ 49 = 72

or alternatively (in ascii form):

m ^ 6 = [
o ^ 8 = W
n ^ 1 = _
e ^ 3 = V
y ^ 1 = H

So "[W_VH" = "money" ^ "68131"

You can then reverse this process to give you the plaintext:

[plaintext-character] = [ciphertext-character] XOR [key-character]

91 ^ 54 = 109
87 ^ 56 = 111
95 ^ 49 = 110
86 ^ 51 = 101
72 ^ 49 = 121

or alternatively (in ascii form):

[ ^ 6 = m
W ^ 8 = o
_ ^ 1 = n
V ^ 3 = e
H ^ 1 = y

So "money" = "[W_VH" ^ "68131"

-------------------------------------

I hope this means something to you.. I've just thrown together a little example of XOR encryption using a one-time-pad there. It's a pretty simple concept and might get your feet wet if you hadn't seen it before..

If you don't know what XOR is or does, check out the wiki: http://en.wikipedia.org/wiki/Exclusive_or and it'll give you the truth-tables for it. It's a pretty simple concept and I'm sure reading around will get your head around it if you haven't already.
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Re: Decryption/Encryption Tutorials and Basics

Post by Arhk on Wed Jun 17, 2009 11:00 pm
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http://isohunt.com/torrent_details/4066 ... ab=summary
nice set, it has some good classics...
~ Not until I read "Hack The Stack - Using Snort And Ethereal To Master The 8 Layers Of An Insecure Network (2006)" I realized cryptography was a big deal ( my previous theories just lead me to believe that any crypt that wasn't gibberish could be bruted in a simple matter). The book goes over IP & flaws in relative depth hence hack the stack.
~ Binary is my acid for the next 5 or so years....
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Re: Decryption/Encryption Tutorials and Basics

Post by daedeluslanthanien on Thu Jun 18, 2009 2:40 am
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I LOVE encryption. You must read David Kahn's "The Codebreakers" I read this book years ago, but it is very very relevant. Until you digest this I doubt you would need more material. No, I do not know how to get a magnetically levitated cesium atom....

daed
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Re: Decryption/Encryption Tutorials and Basics

Post by Arhk on Thu Jun 18, 2009 7:57 am
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I've heard good things about "The Codebreakers" wikipedia talks it up saying NSA didn't like it revealing as much as it did....
~ THe whole hack the stack book didn't teach any cryptography just talked how it's used leading me to realize its importance
~ "The Codebreakers" is apart of that link...
~ Binary is my acid for the next 5 or so years....
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Re: Decryption/Encryption Tutorials and Basics

Post by hormazd7 on Fri Jul 24, 2009 6:35 am
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could any of ull temme how to get started like what the basics are and stuff and where and how i should go around stuuf
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Re: Decryption/Encryption Tutorials and Basics

Post by thedotmaster on Sat Jul 25, 2009 6:43 am
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A very useful tool is CrypTool, which can be found here: https://www.cryptool.org/
Will help a lot when learning about cryptography.
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