Luigi Auriemma

aluigi.org (ARCHIVE-ONLY FORUM!)
It is currently 19 Jul 2012 11:54

All times are UTC [ DST ]





Forum locked This topic is locked, you cannot edit posts or make further replies.  [ 3 posts ] 
Author Message
 Post subject: Crypto system
PostPosted: 04 Jul 2011 14:24 

Joined: 04 Jul 2011 14:10
Posts: 2
Hi,

I want to find the algorithm coded in one arm cpu.

I have:
- the mcu dump file that crypt datas,
- uncrypted texts, (hex: E503565758375A30474E334E3631534F)
- cypher texts, (hex: 20E2926EAE64205DF872C7514DA6F9BA)
- key (48 bit) (hex: 4119835C8464)

I know it is a symetric algorythm.
uncrypted text and cypher text always have the same length.

When I run signsrch on the bin file, i get:

offset num description [bits.endian.size]
--------------------------------------------
00026cc4 163 AES Rijndael Logtable [..256]
00026dc4 164 AES Rijndael Alogtable [..256]
00026ecc 165 AES Rijndael S / ARIA S1 [..256]
00026fec 166 AES Rijndael Si / ARIA X1 [..256]
00026fd3 1636 Noekeon Nessie round [..17]

- 5 signatures found in the file


Please can you help me to find the crypto algorythm.
When I try with rijndael, I don't find good value.

I don't know wich mode to use (CBC, ECB...),
I dont know iv (initialisation vector) and,
AES Rijndael normally use 256 bits heys isn't it ?

Thanks for your help.

regards,

Krafeus


Top
 Profile  
 
 
 Post subject: Re: Crypto system
PostPosted: 04 Jul 2011 19:17 

Joined: 13 Aug 2007 21:44
Posts: 4068
Location: http://aluigi.org
aes needs a key of 128, 192 or 256 bits so if the algorithm is aes then the key is invalid.

ecb doesn't use ivec but the others do so there is an additional problem to add in case it's aes non-ecb

maybe it's a custom algorithm but in that case don't know where starting


Top
 Profile  
 
 Post subject: Re: Crypto system
PostPosted: 04 Jul 2011 21:32 

Joined: 04 Jul 2011 14:10
Posts: 2
Hi aluigi,

Thanks for your quick answer.

Regards,

Krafeus


Top
 Profile  
 
Display posts from previous:  Sort by  
Forum locked This topic is locked, you cannot edit posts or make further replies.  [ 3 posts ] 

All times are UTC [ DST ]


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for: