Building Secure and Watchtower efficient Bitcoin Payment Channels with BitVMX
summary
Introduces a channel that uses one-time signatures to make watchtowers require constant space (about 2KB per channel) and only the last two revocation transactions, with per-bit OTS cost ≈32 weight units (a 32-bit value ≈500 vbytes). Cooperative close uses three small transactions; unilateral exit costs ~700 wu and a disputed exit adds ~750 wu. Integration with BitVMX/BBMX runs a RISC‑V virtual CPU verification game, needs two extra OTS keys, and promises dispute costs cut from ~$80 to ~16 using garbled-sequence proofs.
AI-written summary · about
chapters (13)
- 0:00Introduction
- 1:05Payment channels need
- 3:15Payment channel designs
- 6:45One-time signatures role
- 10:21One-time signature channels
- 14:13Protocol setup and updates
- 17:01Penalization and exit
- 19:30Closing channels and HTLC
- 21:40Watchtower efficiency and privacy
- 22:21BitVMX capabilities
- 26:15BitVMX for channels
- 28:47Summary and future
- 31:57Q&A
