  Growing excitement around permissionless blockchains is uncovering its latent
scalability concerns. Permissioned blockchains offer high transactional
throughput and low latencies while compromising decentralization. In the quest
for a decentralized, scalable blockchain fabric, i.e., to offer the scalability
of permissioned blockchain in a permissionless setting, we present L4L to
encourage decentralization over the permissioned Libra network without
compromising its sustainability. L4L employs delay towers, -- puzzle towers
that leverage verifiable delay functions -- for establishing identity in a
permissionless setting. Delay towers cannot be parallelized due to their
sequential execution, making them an eco-friendly alternative. We also discuss
methodologies to replace validators participating in consensus to promote
compliant behavior. Our evaluations found that the cost of enabling
decentralization over permissioned networks is almost negligible. Furthermore,
delay towers offer an alternative to existing permissionless consensus
mechanisms without requiring airdrops or pre-sale of tokens.
