PowPeg and the security model
The PowPeg is Rootstock's Bitcoin-native two-way peg. It locks BTC on Bitcoin and the Bridge releases rBTC 1:1 to the user (peg-in). Peg-out returns rBTC to the Bridge and releases BTC. All 21M rBTC exists from genesis. The Bridge holds the locked portion. This page summarizes PowPeg-specific security properties. Published audits and disclosures live in the security repository.
How the PowPeg is secured
Because Bitcoin does not support Turing-complete contracts or native opcodes to validate external SPV proofs, part of the two-way peg relies on an autonomous PowPeg system:
- The Bridge precompiled contract controls peg operations on Rootstock.
- Pegnatories each run a
powpeg-nodeand a PowHSM. - The PowHSM stores a private key share in a secure element and signs peg-outs only when Rootstock presents sufficient cumulative proof of work.
No single pegnatory can control locked BTC or access the multi-sig private key in the PowHSM. Not even a majority of pegnatories can release BTC without a valid Bridge command backed by enough cumulative work. Peg-out signing requires on the order of 4000 Rootstock confirmation blocks (about 100 Bitcoin blocks of cumulative work; about 200 Bitcoin blocks wall-clock). Confirm live thresholds in Bridge and PowHSM docs when you integrate.
The federation currently signs as 5-of-9, expanding toward 20 members. See PowPeg member updates for composition-change phases (vote, delay, migrate).
Defense in depth
PowPeg security is one layer of Rootstock's broader model:
| Layer | What it does |
|---|---|
| Merged mining | Ties Rootstock consensus to Bitcoin hashpower (85%+) |
| Bridge contract | Builds peg-out transactions and enforces rules |
| PowHSM | Signs only work-backed commands |
| SSDLC + Coinspect | Continuous review of rskj and powpeg-node |
| Bug bounty + attestation | External research and public firmware proofs |
Read next
- Security repository: audits, disclosures, and Coinspect reports
- PowPeg protocol: peg-in / peg-out architecture
- HSM firmware attestation