useful things about asymmetric keys make them weak and AES is weak anyway

Posted Mar 20, 2004 0:29 UTC (Sat) by hipparchus (guest, #20252)
In reply to: Do the math and some thinking.... by ekj
Parent article: Mainstream means more malicious code for Linux (SearchSecurity.com)

As you know asymmetric keys are a whole lot harder to make than symmetric keys. The "useful" things about them are that you can distribute a public key, and keep a private key hidden.
The whole principle is that the author keeps the private key, encrypts or "signs" data, and people with the public key can verify the data sent by the author to be his work.
The problem is by the nature of the above system, the keys cannot easily be thrown away. You might have documents all over the web signed by the author, and numerous clients with the public key who you'd have to distribute a new public key to (they'd have to keep your old public key to verify old documents they might have stored, too).

If you start by the premise that you (analogy) change your locks on a regular basis, you're system is a lot more secure.
I've provided a way in which authentication can happen irrespective of symmetry of keys.

GZILLION YEARS TO CRACK AES:
You should know the NSA make ASICs with hard wired asymmetric decode hardware which can decode something like 5000 encrypted messages per second. Imagine a large circuit board with 200 chips like this on it, then multiply by 20 in a 6ft tall 19 inch rack. Then multiple by say 10 6ft tall racks.
So now you're talking decoding 200 million encrypted messages per second, hardly the gzillions of years for one key.

Re: AES is weak anyway

Posted Mar 26, 2004 18:35 UTC (Fri) by robbe (guest, #16131) [Link] (2 responses)

Brute forcing a 128-bit key with 2*10⁸ trials per second still takes more than 26 sextillion (2.6*10²²) years (quite close to what people would term a "gzillion").

Calculating the years needed if computing power doubles every 18 months is left as an exercise to the reader.

Of course this says nothing about a rubber hose, cryptoanalysis, or brute-forcing the INPUT bits to the key (i.e. the possible passphrases), all of which will bring success in less than a century.

asymmetric keys have few solutions

Posted Mar 27, 2004 1:01 UTC (Sat) by hipparchus (guest, #20252) [Link]

Asymmetric keys are far less strong than symmetric keys. Note in the case of AES, the NSA (and perhaps many other people) already know the algorithm.
Therefore you have to brute force only a relatively small number of possible solutions.

What you get in trade off for the lack of strength is .... asymmetry (public and private keys).

I propose using symmetry instead, and totally discardable keys.

read this about DES for example, and go figure about AES

Posted Mar 27, 2004 1:41 UTC (Sat) by hipparchus (guest, #20252) [Link]

Please note AES is in itself a symmetric block cipher of say 128 or 256 bit size. HOWEVER the recommended imlementation for exchange of the cipher is public/private key encryption. (see my above mail about small number of solutions):

out of interest: DES cracker (they said it was uncrackable).

http://www.eff.org/Privacy/Crypto_misc/DESCracker/HTML/19980716_eff_des_faq.html#howsitwork

discussion on implementation of AES:

http://66.102.11.104/search?q=cache:OKqHzqpn-RcJ:www.parallaxresearch.com/dataclips/pub/infosec/cryptology/guidelines/STOA-Report3-5.pdf+nsa+chips+to+decode+aes&hl=en&ie=UTF-8