On Sat, 25 Feb 2006 01:29:49 +0000 (UTC),
ro******@ibd.nrc-cnrc.gc.ca
(Walter Roberson) wrote:
In article <11**********************@i39g2000cwa.googlegroups .com>,
lnzju <ge*******@gmail.com> wrote:I mean to write the DES Algorithm myself.
I'm sure you can find plenty of DES encryption programs by
just googling for them.
That's certainly true.
Unless, that is, your government [China] is blocking those sites:
if so then it might not be the best of ideas for us to post the
algorithm.
I don't see why -- most of us (including apparently you and certainly
me) live under governments that allow it. Even during the days of ITAR
the US officially only prohibited implementations, not algorithms. The
worst that could happen is that he wouldn't see it, which would leave
him no worse off than now.
There are certainly lots of places to find the algorithm as well, but
if you want an official one, it's at csrc.nist.gov, the Computer
Security Resource Center of the National Institute for Standards and
Technology of the Commerce Department, successor to the National
Bureau of Standards which originally published it. The slightly tricky
bit is that it's no longer officially a "FIPS" (Federal Information
Processing Standard); after being superseded by AES (the Advanced
Encryption Standard, FIPS 197, aka Rijndael) FIPS 46-3 was withdrawn,
but the document is still available, and the same _algorithm_ DEA is
still specified as part of TDEA (usually called triple-DES or 3DES) in
Special Publication 800-67.
In case the OP or anyone else doesn't know, I will point out that
(classic, single) DES/DEA is now in reach of brute force attack and
not secure again a serious adversary. If you actually want _security_,
not specifically DES, use something better. The simplest and usually
easiest is AES; if you don't want that, sci.crypt is a good place to
learn about other choices. (After you explain why not AES.)
- David.Thompson1 at worldnet.att.net