Commitment Scheme
Definition
A commitment scheme allows a party to commit to a value while keeping it hidden, then later reveal the value while proving it matches the original commitment. This provides binding (cannot change the value) and hiding (value remains secret until reveal).
Technical Explanation
Hash-based commitments are common: commit by publishing H(value || randomness), reveal by disclosing value and randomness. The hash's preimage resistance ensures hiding; collision resistance ensures binding. More sophisticated schemes use algebraic structures for additional properties.
Post-quantum commitment schemes must resist quantum attacks. Hash-based commitments using SHA-3 or SHAKE remain secure—quantum computers don't efficiently break preimage or collision resistance. Pedersen commitments (algebraic) may need post-quantum alternatives.
SynX Relevance
SynX uses commitment schemes for various protocol features including atomic swaps and timed releases. All commitments use quantum-resistant hash functions (SHA3-256/SHAKE256), ensuring the binding and hiding properties persist against quantum adversaries.
Frequently Asked Questions
- Where does SynX use commitments?
- In HTLCs for swaps, randomness generation, and certain privacy features.
- Can quantum computers break commitments?
- Not hash-based commitments—SynX uses quantum-resistant hash functions.
- What happens if a commitment is never revealed?
- The committed value remains hidden forever; protocol timeouts handle uncompleted flows.
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