11 Nov
2013
11 Nov
'13
4:42 p.m.
On Sun, Nov 10, 2013 at 9:54 AM, Andy Isaacson
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.