Privacy Engine

The Privacy Engine is the computational core that transforms private transaction data into verifiable public proofs:

Components:

1. Commitment Manager

   • Generates cryptographic commitments for transaction values

   • Tracks UTXO set (unspent commitments) locally

   • Manages commitment randomness and secrets

   • Handles commitment consolidation when UTXO set grows large

2. Proof Generator

   • Compiles circuit constraints and witness data

   • Executes proving algorithm (Groth16 or PLONK)

   • Generates proofs that satisfy circuit constraints

   • Optimizes proof generation for browser environments

3. Note Encryptor

   • Encrypts transaction details for recipient

   • Uses recipient’s public viewing key

   • Embeds encrypted notes in transaction data

   • Enables recipient to decrypt and track incoming payments

4. Nullifier Generator

   • Creates unique nullifiers from spent commitments

   • Ensures double-spend prevention

   • Links to spending key without revealing it

   • Maintains cryptographic unlinkability

Proof Generation Pipeline:

Private Inputs → Circuit Witness → Proving Algorithm → Proof
     ↓
[Amount, Keys,    [Constraint      [FFT, Polynomial    [π_a, π_b, π_c]
 Commitments,      Satisfaction]     Commitments]       + Public Signals
 Randomness]