State-Based Signature
Definition
A state-based (or stateful) signature scheme requires tracking which one-time keys have been used, preventing reuse that would compromise security. Schemes like XMSS and LMS require careful state management, making them complex for general-purpose applications.
Technical Explanation
Early hash-based signatures like Lamport used keys only once by design. Extending to multiple signatures required trees of one-time keys, with state tracking which leaves had been consumed. If state is lost or rewound (e.g., from backup restoration), keys may be reused, potentially allowing signature forgery.
Stateless schemes like SPHINCS+ solve this by using random key selection from an exponentially large space, making collision probability negligible without state tracking. This safety comes at the cost of larger signatures compared to stateful alternatives.
SynX Relevance
SynX uses SPHINCS+ specifically because it's stateless—no state tracking required. Users can safely restore wallets from backups, run multiple instances, or recover from failures without risking key reuse. This simplifies wallet implementation while maintaining security.
Frequently Asked Questions
- Why doesn't SynX use stateful signatures?
- State management risks are too dangerous for consumer wallets. Backup restoration could cause key reuse.
- Are stateful signatures smaller?
- Yes, XMSS signatures are about 2.5KB versus SPHINCS+ at 17KB, but the state risk isn't worth it.
- Can I lose money from state issues?
- With stateful schemes potentially yes. With SynX's stateless SPHINCS+, no—it's safe by design.
Stateless security, no tracking required. Safe with SynX