According to well-informed sources in Her Majesty's Government,
Pete Chown <[EMAIL PROTECTED]> wrote:
>This is a bit late since the patent expires in September. However,
>what do people think about this scheme? Firstly is it
>cryptographically reasonable, and secondly does it genuinely avoid the
>scope of the patent?
>
>Whereas in RSA you form a modulus n as the product of two primes p and
>q, in my scheme you set n = pqr, where all three are prime. The order
>of the multiplicative group modulo n is now (p - 1)(q - 1)(r - 1).
>You choose e and find d such that de is congruent to 1 modulo
>(p - 1)(q - 1)(r - 1).
>
>This will now behave in all respects identically to an RSA key,
>although you will have to make the modulus bigger for identical
>security. In fact, someone who is given e and n will find it almost
>impossible to prove that it is not a genuine RSA key.
>
>You could make a key like this into an X.509 certificate. The public
>side will work with all software, since proving that it is not an RSA
>public key involves factoring n and so is computationally infeasible.
>The private half should work with just about all software, since it
>has no reason to recalculate e and d.
It's a nice idea, but it's been around for ages. RSA has always
seemed confident that the general description of the RSA mechanism (claim
33, which doesn't ennumerate the number of primes;-) in the Stateside RSA
patent covers it. (YMMV)
Even if it is not a RSApkc "patent workaround," however, it may be a
potentially useful formulation of PKC.
[I don't think RSA (or anyone else, AFAIK) has thus far used it in a
commercial product or included it in BSAFE or any other toolkits. Dunno why
not. I do know that RSA, at least, explored in some depth its potential for
speeding up (~X2) crypto calculations at the server in C/S interactions. ]
A Compaq crypto team has also done research in this area, using
different numbers of primes with RSA.
(There may even be an old paper from RSA Labs on it. I'll see if I
can find it. If it is not proprietary -- I'll send it along.)
Suerte,
_Vin
--------
"Cryptography is like literacy in the Dark Ages. Infinitely potent, for
good and ill... yet basically an intellectual construct, an idea, which
by its nature will resist efforts to restrict it to bureaucrats and others
who deem only themselves worthy of such Privilege."
_A Thinking Man's Creed for Crypto _vbm
* Vin McLellan + The Privacy Guild + <[EMAIL PROTECTED]> *
