Quantumroot: Quantum-Secure Vaults for Bitcoin Cash

Quantumroot is a quantum-secure Taproot. This repo contains a complete developer preview of a baseline contract implementation: a single-signer `Quantumroot Schnorr+LM-OTS Vault.

The Quantumroot Schnorr+LM-OTS Vault is fully implemented in CashAssembly, including all private key derivation, address generation, and the quantum signing scheme. Wallets can compile transactions directly from the template using any HD Key – no template-specific code.

For more information, see the full Quantumroot post:

Quantumroot: Quantum-Secure Vaults for Bitcoin Cash (bitjson.com) →

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Example Transactions

For ease of review, this repo exports two example transactions, Pre-Quantum Aggregation and Post-Quantum Aggregation.

• The Pre-Quantum Aggregation transaction demonstrates the most privacy-preserving aggregation – Introspection-based cross-input aggregation – where all inputs spend UTXOs from the same address, i.e. no leaks of other wallet addresses.
• The Post-Quantum Aggregation transaction demonstrates both cross-input aggregation and a more specialized aggregation – CashToken-based cross-address aggregation – where UTXOs from multiple addresses are spent using the same quantum signature. (Strong privacy can still be achieved before and after such transactions, e.g. with ZKP covenants.)

Pre-Quantum Aggregation

Pre-Quantum Aggregation spends 20 inputs:

• Input 0: a schnorr spend of Address A
• Input 1 through 19: introspection spends of Address A

Post-Quantum Aggregation

Post-Quantum Aggregation spends 8 inputs. Address Q is a

• Input 0: includes the authorizing CashToken and quantum spend of Address Q
• Input 1: a token spend of Address A
• Input 2: a token spend of Address B
• Inputs 3 and 4: introspection spends of Address A
• Inputs 5 and 6: introspection spends of Address B
• Input 7: introspection spend of Address Q