This post considers “staking”, the practice of using cryptographic coins or tokens to participate in some functional or governance role(s) within a decentralized (blockchain) production effort. The classic example is Proof of Stake (PoS) consensus, where token holders collectively perform the task of maintaining consensus and creating new blocks. This function is performed by Proof of Work miners in Bitcoin.
The term “staking” is now used much more broadly, including Delegated Proof of Stake systems and also hybrid forms.
This post introduces the concept of a majority (51%) attack and gives a short account of the role that Decred’s voters play in defending against these. I will briefly describe how majority attacks against Proof of Work (PoW) currencies work first, then explain how the additional Proof of Stake (PoS) component changes the dynamic in Decred’s case.
Performing a double spend attack means having the power to reorg (reorganize, or rewrite) the blockchain.