# Edinburgh & Connecticut Unis, IOHK (2018) ###### tags: `PoS`, `security`, `long-range`, `axel` ## Summary This paper puts forward a variant of the long-range attack that could impact proof-of-stake blockchains. Long-range attacks are explained in “Securing Proof-of-Stake Protocols”. This particular attack does not rely on posterior corruption, and it can work so long as (1) there are no frequent checkpoints in the blockchain, (2) there are transaction fees and they are used as reward, (3) validated transactions can be transferred to the malicious blockchain (4) low-growth chains are not refused too soon. It consists of an attacker that continuously copies actual transactions into his malicious blockchain, progressively increasing its stake and power over it. ## Comments Very specific, but quite detailed and serious. However, the necessary conditions for the attack to be possible seem too restrictive, meaning that actually achieving this attack appears unlikely. Probably not worth reading if it doesn’t fit your theme.