Two-way peg
Also · Peg · Peg-in · Peg-out · Bridge
A two-way peg is the mechanism that moves bitcoin into a sidechain or rollup and back. Who can release the locked BTC defines how much trust the whole system requires.
A peg-in locks BTC in an output on Bitcoin and credits the same amount on the other chain. A peg-out destroys that credit and releases the BTC. The hard part is the release. Bitcoin cannot verify what happens on another chain, so someone or something must decide that a withdrawal is legitimate.
Liquid delegates that decision to a federation, 11 of 15 signers. Rootstock to a federation whose hardware modules also check Bitcoin proof of work. Citrea and other rollups use BitVM so that a single honest party can block a fraudulent withdrawal. None of these is native to Bitcoin the way a Lightning channel is. That is why our map draws peg links differently from native links.
In French · Peg bidirectionnel (two-way peg)
