[7328] in cryptography@c2.net mail archive
mysterious polish certificate
daemon@ATHENA.MIT.EDU (Markku-Juhani Saarinen)
Fri Jun 16 12:19:27 2000
Date: Fri, 16 Jun 2000 16:35:35 +0300 (EET DST)
From: Markku-Juhani Saarinen <mjos@cc.jyu.fi>
To: cryptography@c2.net
Cc: ben@algroup.co.uk, pgut001@cs.auckland.ac.nz, kravietz@alfa.ceti.pl
Message-ID: <Pine.GSO.4.10.10006160959320.9383-100000@tukki>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=ISO-8859-1
Content-Transfer-Encoding: 8BIT
I wrote:
>> My first guess is that openssl does not work correctly when
>> the length is not divisible by eight. Does this certificate actually
>> *work* ?
Ben Laurie:
>It shouldn't be a problem to have odd-sized moduli.
Yup, actually the private key for the public key certified by the
Mysterious Polish Certificate is (computed using my factorization from
yesterday):
d = 30583757702412054338248862564530603930167546267161
64632993976708185854045053662176785522483239260125
48772660617022493381389757894937929607030767904489
473
Usually RSA implementations can only handle a modulus that
is a product of two primes (this one has seven). No problems
with the public key ops, but the computation of Phi(n) is a bit more
complicated and the usual CRT private key trick won't work.
Further observations:
o The public key of the recipient of this certificate actually has a
_negative_ modulus n, which was converted to -n by OpenSSL !
o The issuer "oi-wbd" is apparently Osrodek Informatyki - Wojewódzki Bank
Danych .. what ever that is.
My second guess that someone simply messed with this cert with a hex
editor. No bugs in OpenSSL implied.
Cheers,
- mj
Markku-Juhani O. Saarinen <mjos@jyu.fi> University of Jyväskylä, Finland
