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# Compressed Account Merkle Proof Circuit

Zero-knowledge circuit that proves ownership of a compressed account in a Merkle tree without revealing the account details.

## What It Does

The circuit verifies:
1. **Account Hash** - Computes Poseidon hash of account fields (owner, discriminator, data)
2. **Merkle Inclusion** - Proves the account exists at a specific leaf in a 26-level tree

## Setup & Testing

```bash
# Compile circuit and generate keys
./scripts/setup.sh

# Run tests
cargo test-sbf

# Clean build artifacts
./scripts/clean.sh

​
Circuit I/O

Public inputs (visible in proof):
  • owner_hashed, merkle_tree_hashed, discriminator - Account identifiers
  • issuer_hashed - Credential issuer
  • expectedRoot - Merkle tree root
  • verification_id - Context for nullifier generation (prevents reuse in same context)
  • public_encrypted_data_hash - Encrypted data commitment
  • nullifier - Unique value preventing double-spending (Poseidon(verification_id, credential_secret))
Private inputs (hidden):
  • credentialPrivateKey - Secret key proving credential ownership
  • leaf_index, account_leaf_index - Account positions
  • address - Account address
  • pathElements[26] - Merkle proof path
  • encrypted_data_hash - Private data hash

​
Circuit Files

  • compressed_account_merkle_proof.circom - Main circuit that combines all components
  • credential.circom - Keypair verification for credential ownership
  • compressed_account.circom - Computes Poseidon hash of account fields
  • merkle_proof.circom - Binary Merkle tree inclusion proof

​
Architecture

CompressedAccountMerkleProof (main)
├── Keypair (credential.circom)
│   └── Proves knowledge of private key
├── CompressedAccountHash (compressed_account.circom)
│   └── Poseidon hash of 6 fields
└── MerkleProof (merkle_proof.circom)
    └── 26-level binary tree verification