GNUnet PoWs hashfunction

[Schanzenbach, Martin]

Hello *,

while writing the specification LSD0001 for GNS, we also address the 
proof-of-work function for zone revocations.
Currently, we use scrypt [0].

Now, there are (not so) new alternatives such as argon2 [1] which claim to 
offer better resistance against AISCs and other custom hardware.

The parameters for Argon2 work a bit differently than for scrypt.
It primarily has:

1. Number of iterations
2. Memory
3. Parallelism (threads)

I am currently implementing the PoW [2] with the following parameters:

1. Iterations: 3 (default)
2. Memory: 1 MiB (so that devices with little memory can still verify the PoW)
3. Parallelism: 1 (none)

I left the WORKBITS (difficulty) for the GNS Zone Revocation PoW unchanged at 
25.

Ideally, the PoW should take ~1 week. I am not sure yet if the chosen 
parameters fit this requirements.
If you have any input on parameter choice or can run a revocation (with the 
argon2 code from that branch) on your device with 17-25 WORKBITS that would 
help greatly.
You will need to have libargon2 installed.

BR
Martin

[0] https://tools.ietf.org/html/rfc7914
[1] https://github.com/P-H-C/phc-winner-argon2
[2] 
https://git.gnunet.org/gnunet.git/tree/src/util/crypto_pow.c?h=schanzen/argon_pow#n49

signature.asc
Description: Message signed with OpenPGP