Hi,

I am searching attaks that work on the IDEA (complete 8 round) algorithm. I have found a paper entitled:New Weak-Key Classes of IDEA
by Alex Biryukov, Jorge Nakahara Jr, Bart Preneel, Joos Vandewalle.
I am familiar with the IDEA algo because I have implemented it in C as a part of my homework.
the problem is that I dont understand the Boomerang attak.
Here is the paper:
h++p://www.cosic.esat.kuleuven.be/publications/article-189.pdf
On page 4:
what is a differential pattern?
what is the definition of the reversed DELTA sign?
Is there anyone familiar with this attak who could explain it to me?

Thanks in advance

Akimp3

You ought to read the original paper by David Wagner.

http://www.cs.berkeley.edu/~daw/papers/boomerang-fse99.ps
slides
http://www.cs.berkeley.edu/~daw/papers/boomerang-fse99-slides.ps

And also Kelsey/Kohno/Schneier's paper turning it into a chosen-plaintext attack.

http://www.cse.ucsd.edu/users/tkohno/papers/FSE00/

PS if you still don't get it after reading those, let me know and I'll try to help.

Hi

Thank you very much for your help. I will read those papers and contact you if I dont undersatand them.

Best Regards

Akimp3