🚀 go-pugleaf

JAMES LEWIS NANCE (jlnance@eos.ncsu.edu) wrote:
: 
: I have been reading a 1988 paper by Miyaguchi, Shiraishi, and Shimizu in which
: they describe an encryption algorithm they call FEAL-8.  I am interested in
: this algorithm because it was designed to run quickly on computers.  I have 
: never heard of it anywhere before and I have the following questions about it.
: Can anyone help me?
: 
: 1) Is FEAL-8 Secure (as compared to DES)?

It's not as secure as DES.  There is a chosen plaintext attack which
can crack FEAL-8 (when used in ECB mode) with a couple of thousand
encryptions.  This does require, however, that the FEAL-8 user encrypt
these plaintexts sent to him by an attacker.  This attack isn't a
problem if:

a.  You change keys frequently, by using a key exchange method such as
Diffie-Hellman or RSA.
b.  You never use ECB mode, but use CBC instead.

FEAL-32 (FEAL with 32 rounds) appers to be as resistant to
cryptanalysis as DES, at least for the time being.

: 2) Is C source code available for it anywhere?

There's no need.  The algorithm is trivial, and any competent C
programmer should be able to code it in a few hours.  I recommend the
use of assembly for high speed implementations.

: 3) Is it patented

Not as far as I know.

: 4) Is it a good choice for a fast, secure private key method?

Probably not, because of the vulnerability to attack mentioned in the
answer to question 1.  IDEA is an alternative, but is patented.  I
suggest you also look as Khufu, which was described recently in one of
the CRYPTO proceedings (I think '91?).  This is a cipher from Xerox
PARC, designed by Ralph Merkle.  I think it's patented too.
 
Andrew.