[145162] in cryptography@c2.net mail archive
Re: Question regarding common modulus on elliptic curve cryptosystems
daemon@ATHENA.MIT.EDU (Jonathan Katz)
Mon Mar 22 11:44:51 2010
Date: Mon, 22 Mar 2010 08:56:49 -0400 (EDT)
From: Jonathan Katz <jkatz@cs.umd.edu>
To: Sergio Lerner <sergiolerner@pentatek.com>
cc: cryptography@metzdowd.com
In-Reply-To: <4BA68BDE.3010007@pentatek.com>
[Moderator's Note: please don't top post... --Perry]
Sounds like a bad idea -- at a minimum, your encryption will be
deterministic.
What are you actually trying to achieve? Usually once you understand that,
you can find a protocol solving your problem already in the crypto
literature.
On Sun, 21 Mar 2010, Sergio Lerner wrote:
>
> I looking for a public-key cryptosystem that allows commutation of the
> operations of encription/decryption for different users keys
> ( Ek(Es(m)) = Es(Ek(m)) ).
> I haven't found a simple cryptosystem in Zp or Z/nZ.
>
> I think the solution may be something like the RSA analogs in elliptic
> curves. Maybe a scheme that allows the use of a common modulus for all users
> (RSA does not).
> I've read on some factoring-based cryptosystem (like Meyer-Muller or
> Koyama-Maurer-Okamoto-Vantone) but the cryptosystem authors say nothing about
> the possibility of using a common modulus, neither for good nor for bad.
>
> Anyone has a deeper knowledge on this crypto to help me?
>
> Best regards,
> Sergio Lerner.
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