Double Spend
Definition
Double spending is attempting to spend the same cryptocurrency twice—sending the same coins to two different recipients. Blockchains prevent double-spending through consensus mechanisms that order transactions. Quantum attacks could theoretically enable double-spends on vulnerable chains.
Technical Explanation
Double-spend methods: race attack (simultaneous conflicting transactions), Finney attack (pre-mine block with reverting transaction), and 51% attack (rewrite chain history). All exploit timing between broadcast and confirmation.
Quantum threat: if quantum computers could forge signatures, attackers could create conflicting transactions or reverse transactions after confirmation. Post-quantum signatures prevent signature-based double-spend vectors entirely.
SynX Relevance
SynX prevents double-spending through: SPHINCS+ signatures (unforgeable, even by quantum computers), finality guarantees (irreversible after attestation), and consensus ordering (deterministic transaction order). No quantum computer can forge the signatures needed for double-spend attacks.
Frequently Asked Questions
- Can I be double-spent on SynX?
- After finality, no. Even before finality, quantum-resistant signatures prevent forgery-based attacks.
- How many confirmations should I wait?
- For finalized transactions, zero additional—they're irreversible. Pre-finality, wait for block confirmations.
- Do quantum computers enable new double-spend attacks?
- On vulnerable chains, yes. SynX's post-quantum design eliminates these vectors.
Double-spend immune. Final transactions on SynX