  We calculate the probability of success of block-hiding mining strategies in
Bitcoin-like networks. These strategies involve building a secret branch of the
block-tree and publishing it opportunistically, aiming to replace the top of
the main branch and rip the reward associated with the secretly mined blocks.
We identify two types of block-hiding strategies and chart the parameter space
where those are more beneficial than the standard mining strategy described in
Nakamoto's paper. Our analysis suggests a generalization of the notion of the
relative hashing power as a measure for a miner's influence on the network.
Block-hiding strategies are beneficial only when this measure of influence
exceeds a certain threshold.
