Encryption module

[Geniis]

This is just a simple little module i coded named Crypto that can encrypt and decrypt files. Its easy to use, its explained in the readme. Just use Crypto.EncriptFile to encrypt a file and Crypto.DecryptFile to decrypt a file (i recommend only decrypting files encrypted with Crypto). There is also a way to change the keys used. Leave feed back if you fell like it, or if you find bugs... i might release a better version of it later on.

[SNIPERDUDE]

Great job

+ bits

[mirhagk]

This reminded me of an earlier encryption program I created, it uses a key, and you can create keys for it (that way even if someone has the program they can't do very much cuz need the exact key)

[yazdmich]

mirhagk @ Tue Dec 15, 2009 12:03 am wrote:

This reminded me of an earlier encryption program I created, it uses a key, and you can create keys for it (that way even if someone has the program they can't do very much cuz need the exact key)

I edited your program as a module and added a few features.

[mirhagk]

Ahh code from my very early days of Turing, it makes me realize just how much I've learned over the past 3 years.

I'd suggest allowing the programmer pass in file names in the module's functions, so that it can truly be used as a module. I would then suggest using a better encryption algorithm, a one time pad would actually be pretty good for this scenario, is easy to implement, and is actually the most secure algorithm (so long as it's used right)

[yazdmich]

mirhagk @ Thu Dec 06, 2012 5:46 pm wrote:

Ahh code from my very early days of Turing, it makes me realize just how much I've learned over the past 3 years.

I'd suggest allowing the programmer pass in file names in the module's functions, so that it can truly be used as a module. I would then suggest using a better encryption algorithm, a one time pad would actually be pretty good for this scenario, is easy to implement, and is actually the most secure algorithm (so long as it's used right)

2 things:

I thought I did allow for variable pass-through?

I'm actually relatively new to Turing (and programming in general) so I'm not quite sure how to implement a one-time pad cipher

Turing:

% KEY-BASED ENCRYPTION MODULE BASED ON http://compsci.ca/v3/download.php?id=7033 % MODIFIED AS A MODULE WITH KEY GENERATOR INCLUDED IN MAIN CODE unit module Crypto     export GetKey, In, Out, key, GenKey, Decoded, Encoded     var ind : int     var key := ""     var encode := ""     var msg : string     var msgout : string     var Encoded := ""     var Decoded := ""     var stream : int     var num : int     var cha : string (1)     var name : string     var alphas := "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz,.?\"'()[]{}1234567890<>;!@#$%^&*`~/\\-=_+ "     var cha1 : array 1 .. 92 of string     var used : array 1 .. 92 of boolean     proc GetKey         put "Please enter the name of the key you are using (key must be in key folder)"         get name         open : stream, "keys/" + name, read         if stream > 0 then             read : stream, key             put "Key: ", key         else             put "Error, key not found, make sure its in the key folder and you spelled it right"             quit         end if         close : stream     end GetKey     proc GetKeyInternal (name1 : string)         open : stream, "keys/" + name1, read         if stream > 0 then             read : stream, key         else             put "Error, key not found, make sure its in the key folder and you spelled it right"             quit         end if         close : stream     end GetKeyInternal     proc In (msg, name : string)         GetKeyInternal (name)         encode := msg         Encoded := ""         for x : 1 .. length (encode)             ind := index (key, encode (x))             if ind > 0 then                 Encoded += alphas (ind)             else                 Encoded += encode (x)             end if         end for         msgout := ""     end In     proc Out (msg, name : string)         GetKeyInternal (name)         Encoded := msg         Decoded := ""         for x : 1 .. length (Encoded)             ind := index (alphas, Encoded (x))             if ind > 0 then                 Decoded += key (ind)             else                 Decoded += Encoded (x)             end if         end for         msgout := ""     end Out     proc GenKey         for i : 1 .. 92             used (i) := false         end for         for i : 1 .. 92             cha1 (i) := alphas (i)         end for         for i : 1 .. 92             loop                 randint (num, 1, 92)                 exit when used (num) = false             end loop             used (num) := true             key += (alphas (num))         end for         put "New key: " ..         put key         put "Please enter a name for this key: " ..         get name         open : stream, "keys/" + name, write         write : stream, key         close : stream     end GenKey end Crypto

[mirhagk]

Ah I only really looked at the GenKey method, the only one where variables aren't passed through lol.

A one time pad basically generates a really large list of random characters, and uses this as the key (the key must be as long as the message in order to be perfectly secure).

You can then go through and use some method to encrypt the message in such a way that you can reverse it. A very common method is to use the XOR operator, which basically works by comparing the bits of each number and puts a 1 every time they are different, and 0 every time they are the same, eg:
110001 message
101010 key
=====
011011 result
Then you can XOR the result with one of the values to get the other one:
011011 result
101010 key
=====
110001 message

[yazdmich]

mirhagk @ Thu Dec 06, 2012 11:54 pm wrote:

A one time pad basically generates a really large list of random characters, and uses this as the key (the key must be as long as the message in order to be perfectly secure).

I'm guessing 255 chars long would be best, so that any line passed through can be encrypted. Also, should it be completely random (with repeated characters)?

[AntoxicatedDevil78]

Amazing!!

[mirhagk]

Yep completely random is best. So long as you use the exact same key it will decrypt and encrypt fine. Technically you should have perfect randomness (random in turing isn't fully random), but the concept is the same.

[yazdmich]

Is this good for the key generator?

Turing:

var ind : int     var key : string := ""     var encode := ""     var msg : string     var msgout : string     var Encoded := ""     var Decoded := ""     var stream : int     var num : int     var name : string     var alphas := "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz,.?\"'()[]{}1234567890<>;!@#$%^&*`~/\\-=_+ "     var cha, ind1 : array 1 .. 92 of string     proc GenKey         for i : 1 .. 92             cha (i) := alphas (i)         end for         for i : 1 .. 255             randint (num, 1, 92)             key := key + cha (num)         end for         put "New key: " ..         put key         put "Please enter a name for this key: " ..         get name         open : stream, "keys/" + name, write         write : stream, key         close : stream     end GenKey

[mirhagk]

Yeah that will generate a long enough key (again it's not perfectly secure, but you can't make it perfect without true random numbers).

Just curious, is there any reason for using cha instead of just using alphas?