Layer 2 networks and bridges

A Layer 2 (or similar side system) batches activity and settles back to a base chain (Layer 1) for security. A bridge moves value between chains or layers — and bridges are frequent theft targets.

Cheaper/faster is the pitch; knowing which network your funds are on, and how to return, is the real skill.

A base chain, or Layer 1, is the main record that everyone trusts in the end. A Layer 2 handles many transactions on its own, groups them, and posts a summary or proof back to Layer 1. You get cheaper, faster activity while still leaning on the base chain for final settlement. The details of how it proves the summary is honest differ from design to design.

A bridge connects two separate networks. The common pattern is lock and mint: you lock coins in a contract or account on chain A, the bridge confirms the lock, and matching tokens are created on chain B. Going back reverses it: the tokens on B are burned, and the originals on A are released. The locked pile on chain A is a big target for thieves.

Real example: say you move tokens through a bridge to a cheaper network. Your originals sit locked on the first chain, and you hold stand-ins on the second. If the bridge’s keys or code are broken, the stand-ins can lose their backing. Source: Ethereum.org — Bridges.