Re: [MLS] Re-randomized TreeKEM

Konrad Kohbrok <konrad.kohbrok@datashrine.de> Mon, 21 October 2019 12:31 UTC

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From: Konrad Kohbrok <konrad.kohbrok@datashrine.de>
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Date: Mon, 21 Oct 2019 14:31:04 +0200
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Subject: Re: [MLS] Re-randomized TreeKEM
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Ah, ok I misunderstood. That sounds a lot more feasible :-)

Konrad

On 21.10.19 15:28, Benjamin Beurdouche wrote:
> 
> 
>> On Oct 21, 2019, at 2:20 PM, Konrad Kohbrok <konrad.kohbrok@datashrine.de
>> <mailto:konrad.kohbrok@datashrine.de>> wrote:
>>
>> Hi Karthik,
>>
>> I think you got it right with regard to the additional guarantees gained by
>> RTreeKEM.
>>
>> Regarding your UPKE proposal: Wouldn't A then also have to send the private keys
>> of each key pair to all leaves of the sub-tree blonging to the node that the key
>> pair is generated for? Otherwise, only A could decrypt updates sent to those
>> keys. These private keys would have to be encrypted under some previous one-time
>> key that is subsequently deleted.
> 
> No, I think Karthik suggested to KDF (K=100) keypairs from the new secret
> (instead of K=1 today)
> and immediately kill the received node secret for FS…
> 
> B.
> 
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