25 July 2005, 11:32 | #1 |
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Amiga Format Issue 12, Paul Overaa
Hi
There is a tutorial in AF issue 12 by Paul Overaa, a introduction to encryption on the amiga. Can some one please scan this please. Thanks. |
25 July 2005, 14:02 | #2 |
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I don't have that magazine but what exactly do you want the encryption information for? If it's just for your own project you can just do a basic XOR over the data and that would be enough to protect it from the majority of people.
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25 July 2005, 20:19 | #3 |
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Yeah what's it for? Different types of encryption are more suitable for different purposes so what you want will depend very much on what you are trying to achieve...
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26 July 2005, 10:42 | #4 |
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I remember that Adobe 'Ebooks encryption used to be XOR the data with the string "ENCRYPTED". Some russian got into terrible trouble when he announced this
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27 July 2005, 12:47 | #5 |
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what's it for?!?! it's a secret project :P.
Nah, I just wanna read it, yeah i've read that shit about XORing the data and stuff, but still wouldn't mind reading the article. |
27 July 2005, 14:07 | #6 | ||
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Quote:
Quote:
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29 July 2005, 12:06 | #7 |
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Okay
that's 2 people on the waiting list |
17 August 2005, 17:40 | #8 |
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I have the article but I don't have a scanner. However I've taken the time to copy the BASIC code at the end of the article to text so you can have a read of something. Enjoy!
Code:
File Encryption - A simple Example to give you the general idea. --------------------------------------------------------------- NOTE 1: This example does not contain any error checking! NOTE 2: I wouldn't recommend such a simple function for serious use but as an "easily understood" starting point it does serve a useful purpose. Once you understand the overall ideas you can experiment with more sophisticated functions. NOTE 3: You can add all the bells and whistles you want, but the basic idea is simply this... OPEN SOURCE AND DESTINATION READ AND PROCESS EACH CHARACTER IN THE SOURCE FILE WRITING EACH MODIFIED CHARACTER TO THE DESTINATION FILE CLOSE SOURCE AND DESTINATION FILES REM First step is to get the filenames and a "key" value. INPUT "Source file?", SOURCE$ INPUT "Destination file?", DESTINATION$ INPUT "Encryption file?", Key REM Open the file and initialise a position counter OPEN "i",£1,SOURCE$: OPEN "o",£2,DESTINATION$: Position = 0 REM Now loop reading the source file byte by byte carrying out the REM encryption function on each character and writing the encrypted REM character to the destination file. WHILE (NOT EOF(1)) CHARACTER$ = INPUT$(1,£1): X = ASC (CHARACTER$) : Position = 1 X = X XOR ((Key + Position) MOD 256) : PRINT£2,CHR$(X);: WEND REM Close the file and quit CLOSE 1: CLOSE 2: END X = X XOR ((Key + Position) MOD 256) : PRINT£2,CHR$(X);: Last edited by Steve; 17 August 2005 at 17:48. |
17 August 2005, 18:49 | #9 | |
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Off Topic:
Quote:
On Topic: In the listing above, aren't those pound signs (£) supposed to be pound signs (#) ? Another thing, can anyone figure out what the Position variable is supposed to be for? It gets assigned one constant, then another, then....??? Last edited by OddbOd; 17 August 2005 at 18:55. |
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17 August 2005, 23:00 | #10 |
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Scanned and in the Zone - enjoy!
Last edited by Galaxy; 17 August 2005 at 23:19. |
18 August 2005, 02:19 | #11 |
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Thanks Steve and Galaxy .
Galaxy, Is there a ISO you follow for scanning Amiga Tutorials? I want to buy a scanner, so I can scan in my Amiga magazine Tutorials, because they are really useful. |
18 August 2005, 14:09 | #12 |
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What do you mean by ISO?
There's nothing particularly special about the scans I made - they were scanned as greyscale and then converted to pdf. |
19 August 2005, 01:02 | #13 |
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any particular DPI ?
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19 August 2005, 02:02 | #14 |
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300dpi is the standard for good readability and should suit most purposes, if you want to blow it up to a larger than life size then scan at a higher resolution.
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19 August 2005, 04:31 | #15 |
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I usually use 300dpi/black and white for this sort of scanning.
In this case I used 200dpi greyscale. |
19 August 2005, 16:48 | #16 |
Mostly Harmless
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Thanks for the scan
Its a sound enough article on basic stream mode encryption. To his credit the author does advise that the algorithms are easily cracked and not to be used for anything you actually want to remain secret Theres one common mistake though: XOR encrypting data more than once with different keys is no more secure than encrypting it once, as the XORs effectively combine all the keys into one. |
20 August 2005, 08:05 | #17 |
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girv: do you use Amitcp:libs/usergroup.library/crypt() ???
I seem to have problem with that function. I dissassembled bin/login, and copied the salt(setting). so when I coded my own routine and tried comparing my crypt() result with the one from bin/login I got a different pw . |
21 August 2005, 04:29 | #18 |
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I've never used that function, sorry.
Are you sure youre using the exact same algorithm in your own code as the library does? |
22 August 2005, 04:18 | #19 |
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I'm actually calling the libraries crypt() function.
but it's interesting because it says in the docs that the salt begins with a underscore '_' let the salt that I get from my code is the first 9 letters of the encrypted password :/ |
22 August 2005, 14:08 | #20 |
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Can you post the code you're using? Also where did you get the library and its autodocs?
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