Reverse Engineering RET Homepage RET Members Reverse Engineering Projects Reverse Engineering Papers Reversing Challenges Reverser Tools RET Re-Search Engine Reverse Engineering Forum Reverse Engineering Links

Go Back   Reverse Engineering Team Board > Reverse Engineering Board > Steganography + Cryptography
FAQ Members List Calendar Search Today's Posts Mark Forums Read

 
 
Thread Tools Display Modes
Prev Previous Post   Next Post Next
  #1  
Old 06-07-2005, 09:30 PM
rwid rwid is offline
Member
 
Join Date: Jun 2005
Location: Sydney, Australia
Posts: 41
Default

Hi reteam,

I've read XOR encryption is very susceptible to crypto analysis attacks where the key length is less than the length of the plaintext. Also XORing multiple keys of lengths divisible by each other does not increase security, eg: XORing the plaintext with a key of length 4 bytes and then XORing the plaintext with a key of 8 bytes is no more secure than simply XORing the plaintext with only an 8 byte key.

But what if I used keys with lengths of prime numbers, and I apply them in the same manner as above, ie one after the other to the plain text?

For example given four keys of lengths 7, 19, 23 and 29 bytes respectively, if I XOR each of these keys one at a time across the plaintext, does this give me an effective key length of 17*19*23*29 = 215441 bytes because these key lengths are all prime?

Would the key still be susceptible to crypto analysis attacks if I had used a plaintext length matching that effective key length (in this example 215441 bytes) ?
Reply With Quote
 


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump





Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2022, Jelsoft Enterprises Ltd.