A SILENT HUB PAYS THE USER — LICHEN’S BABE FIX FOR VARIABLE WITHDRAWALS — BUT YOU GET ONE TRY

On Oct. 18, 2026, at 22:04 UTC, the developer who posts as AdamISZ put a design note on the Delving Bitcoin forum. It is about BABE, a method from a paper by Sanjam Garg, David Tse and three co-authors that lets a bitcoin coin unlock only for someone who holds a valid short proof. The method has a limit he names plainly: “the statement you are proving is fixed at setup time, it is not dynamic.” So the amount to be paid has to be known when the contract is made.

His fix is for Lichen, his own layer 2 project. A hub issues tokens, and each user’s holdings, up to a cap, are backed by bitcoin in her own contract with the hub. The user announces the amount she wants to withdraw with a one-time signature. The hub must sign that same amount “before a timeout, else the money goes to P,” the user. Her proof then has to include the hub’s signature, and the contract forces both numbers to match. The hub cannot stall her by going quiet, and it cannot swap in a different number.

The same post states the cost: “withdrawals from hub-user contracts of this type are one-shot.” A user who starts a withdrawal and fails “can’t try again,” and the contract closes. He says none of BABE’s math changes; only the bitcoin side of the contract does. Lichen’s README says “No change to Bitcoin is needed,” and as of Oct. 18, 2026 it enforces withdrawals with a different tool, BitVMX. The post proposes BABE in its place.

This is a design note, not a release. The repo was created on Oct. 9, 2026, shows 0 stars, lists only test networks, and its README warns “Do not use with real money” because the code is unaudited and was written by an LLM. As of 22:54 UTC on Oct. 18 the post had no replies. What it offers is a way to check on bitcoin that a hub paid you the right amount, instead of trusting the hub. Whether one try is a fair price is for reviewers to test. At the time of this writing, bitcoin was $82,248.