[cryptography] NIST Randomness Beacon

CodesInChaos codesinchaos at gmail.com
Mon Nov 11 11:42:54 EST 2013


On Sun, Nov 10, 2013 at 9:54 AM, Andy Isaacson <adi at hexapodia.org> wrote:
> For example, suppose you use the low bits of the bitcoin blockchain
> hash.  An attacker with 10% of the hash power could probabilistically
> attack such a system by chosing blocks with a specific value in those
> bits;

This can be avoided by running a sequential computation based on that
hash. For example
by hashing it 2^40 times. Obvious downside is that verifying that the
computation was performed
correctly is just as expensive (but parallelizable).

Perhaps there is a function that's sequential and slow in one
direction and fast in the reverse direction.


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