gbadev.org forum archive

This is a read-only mirror of the content originally found on forum.gbadev.org (now offline), salvaged from Wayback machine copies. A new forum can be found here.

Beginners > Feasability of implementation: crytography.

#13175 - xtac - Sun Dec 07, 2003 6:05 am

Is it feasible to implement a simple cipher on a GBA (for example 448bit blowfish), so that data entered on it could be stored and then later retrieved via the flash cart in a secure form.

IE let's say I have a keyboard mod (Keyboard Advance) for the GBA, and I want oo have an *extremely* small secure client (secure because everything is in RAM on a gba), and want to leave stuff for my buddies later, in an inconspicuous package. DOes anyone have a clue how fast the ciphers would run on the 17.whatever MHz processor? Assuming something as simple as DES or as complex as Rijndael.
_________________
[ XtaC ] was here.
.ereh saw [ CatX ]
They both sound normal when you say them, WHY!?

#13181 - tepples - Sun Dec 07, 2003 4:03 pm

TEA is fast. Very fast.
_________________
-- Where is he?
-- Who?
-- You know, the human.
-- I think he moved to Tilwick.

#13191 - xtac - Sun Dec 07, 2003 10:03 pm

Yes, but TEA is also a weaker algorithm ( 16 and 32 bits? ) than most of the others. Thanks for the info, though.
_________________
[ XtaC ] was here.
.ereh saw [ CatX ]
They both sound normal when you say them, WHY!?

#13192 - tepples - Sun Dec 07, 2003 10:08 pm

TEA has a 128-bit key and operates on 64-bit blocks, each made of two 32-bit Feistel half-blocks.
_________________
-- Where is he?
-- Who?
-- You know, the human.
-- I think he moved to Tilwick.

#13401 - torne - Fri Dec 12, 2003 6:29 pm

TEA is believed to be pretty strong.