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#1 |
Zone Friend
Join Date: Mar 2004
Location: Middle Earth
Age: 40
Posts: 2,130
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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. |
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#2 |
2 contact me: email only!
Join Date: May 2001
Location: Auckland / New Zealand
Posts: 3,188
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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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#3 |
Mostly Harmless
Join Date: Aug 2004
Location: Northern Ireland
Posts: 1,159
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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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#4 |
Thalion Webshrine
Join Date: Jan 2004
Location: Oxford
Posts: 14,648
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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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#5 |
Zone Friend
Join Date: Mar 2004
Location: Middle Earth
Age: 40
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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. |
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#6 | ||
Mostly Harmless
Join Date: Aug 2004
Location: Northern Ireland
Posts: 1,159
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Quote:
![]() Quote:
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#7 |
Zone Friend
Join Date: Mar 2004
Location: Middle Earth
Age: 40
Posts: 2,130
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Okay
that's 2 people on the waiting list ![]() |
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#8 |
I Identify as an Ewok
Join Date: Jul 2001
Location: North Lincolnshire
Age: 45
Posts: 2,357
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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. |
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#9 | |
Registered User
Join Date: Jul 2005
Location: Australia
Age: 47
Posts: 666
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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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#10 |
Registered User
Join Date: May 2004
Location: Canberra, Australia
Age: 46
Posts: 1,417
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Scanned and in the Zone - enjoy!
Last edited by Galaxy; 17 August 2005 at 23:19. |
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#11 |
Zone Friend
Join Date: Mar 2004
Location: Middle Earth
Age: 40
Posts: 2,130
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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. |
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#12 |
Registered User
Join Date: May 2004
Location: Canberra, Australia
Age: 46
Posts: 1,417
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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. |
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#13 |
Zone Friend
Join Date: Mar 2004
Location: Middle Earth
Age: 40
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any particular DPI ?
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#14 |
Registered User
Join Date: Jul 2005
Location: nope
Posts: 39
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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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#15 |
Registered User
Join Date: May 2004
Location: Canberra, Australia
Age: 46
Posts: 1,417
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I usually use 300dpi/black and white for this sort of scanning.
In this case I used 200dpi greyscale. |
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#16 |
Mostly Harmless
Join Date: Aug 2004
Location: Northern Ireland
Posts: 1,159
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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. |
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#17 |
Zone Friend
Join Date: Mar 2004
Location: Middle Earth
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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 ![]() |
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#18 |
Mostly Harmless
Join Date: Aug 2004
Location: Northern Ireland
Posts: 1,159
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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? |
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#19 |
Zone Friend
Join Date: Mar 2004
Location: Middle Earth
Age: 40
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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 :/ |
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#20 |
Mostly Harmless
Join Date: Aug 2004
Location: Northern Ireland
Posts: 1,159
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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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