It is an online scheme for resisting sybil attacks in a P2P network where nodes have cryptographic identities which works by periodically forcing all users to do proof of work within a limited time window. Peers that don't respond fast enough are banned from the system (have to create a new identity to join, which is computationally expensive).
The idea is that this get some of the benefits of POW for sybil resistance without spending as much energy.
It doesn't, however, produce a large amount of cumulative work building up over a history. So it's not the sort of thing you'd want to use to protect the history of a ledger directly.
I gave it a fast skim to figure out what general class of thing it actually is.
This should be compared with "proof of idle" (https://www.cs.virginia.edu/~shelat/14s-pet/2014/02/11/proof...).
It is an online scheme for resisting sybil attacks in a P2P network where nodes have cryptographic identities which works by periodically forcing all users to do proof of work within a limited time window. Peers that don't respond fast enough are banned from the system (have to create a new identity to join, which is computationally expensive).
The idea is that this get some of the benefits of POW for sybil resistance without spending as much energy.
It doesn't, however, produce a large amount of cumulative work building up over a history. So it's not the sort of thing you'd want to use to protect the history of a ledger directly.