[cryptography] Homomorphic split-key encryption OR snake oil crypto
James A. Donald
jamesd at echeque.com
Sun Feb 19 16:34:15 EST 2012
On 2012-02-20 2:08 AM, Florian Weimer wrote:
>> Can somebody explain me how this so-called Homomorphic split-key
>> encryption works?
Homomorphic means you combine the keys without finding out the key that
you are combining - Everyone gives you an encrypted copy of their key
fragment, and when you are done, you have an encrypted copy of the
> Isn't this just a protocal which performs a cryptographic primitive
> using split key material, without actually recombining the keys?
> (Traditional Shamir secret sharing needs a trust party for key
> If yes, you might want to look for "RSA Threshold Cryptography" and
> similar work.
My understanding is that RSA Threshold always requires a "trusted"
party, which makes it useless. If you have a party that is actually
trusted, just let him count the votes or whatever. The cryptography
does not do you any good.
The only protocol that I am aware of that performs cryptographic
operations on a split key with needing a trusted party, uses Gap Diffie
All known Gap Diffie Hellman Groups consist of an elliptic curve which
supports a bilinear pairing from the curve to integers modulo some large
More information about the cryptography