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

Ali, Saqib docbook.xml at gmail.com
Sun Feb 19 21:18:03 EST 2012

Hi James,

Exactly. True Homomorphism (or a fully Homomorphic system) does not
require the hosting party to have any knowledge of the key, but still
facilitates computational functions on the data without the need for
decrypting the data.

Having homomorphism is a split key / shared secret (m of n principle)
doesn't make any sense.


On Sun, Feb 19, 2012 at 4:26 PM, James A. Donald <jamesd at echeque.com> wrote:
> On 2012-02-20 7:55 AM, Ali, Saqib wrote:
>> Hi James,
>> I am still not sure why you need homomorphism in this case. What is
>> the benefit of using homomorphism to porticor's customer, for example?
> With RSA split keys, you need a trusted party to combine them - but if the
> trusted party is untrustworthy, you are hosed.  Presumably, with homomorphic
> encryption, the trusted party would perform the operations, but not have
> access to the combined key.
> But I don't think this helps.
> It is a way of getting around the trusted party problem, but I don't think
> it does get around the trusted party problem.

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