[cryptography] Homomorphic split-key encryption OR snake oil crypto

Nico Williams nico at cryptonector.com
Sun Feb 19 11:22:02 EST 2012

On Sun, Feb 19, 2012 at 10:08 AM, Florian Weimer <fw at deneb.enyo.de> wrote:
> * Saqib Ali:
>> Can somebody explain me how this so-called Homomorphic split-key
>> encryption works?
> 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
> recombination.)

The key part is the homomorphism.  ISTR this from a few years ago, and
I see wikipedia has an OK article on the subject:


The idea is that you could even write an entire program this way,
which allows you to run it on untrusted systems without leaking the
program or data to those systems.  It seems unlikely to get deployed
anytime soon.


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