private_vote Circuit

private_vote lets a token holder cast a boolean vote while proving eligibility (balance at least a threshold), committing to both the balance and the vote with Poseidon — without revealing the balance or linking the vote to an identity. Size: k=11.

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What it proves

For the witnesses below and a public threshold, the circuit proves:

1. balance_commitment = Poseidon(balance, randomness_balance).
2. vote_commitment = Poseidon(vote, randomness_vote).
3. vote ∈ {0, 1} — the vote is boolean.
4. balance ≥ threshold — voter eligibility, without revealing the balance.

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Witness

private_vote.json

{
  "balance":            "500",
  "randomness_balance": "11",
  "vote":               "1",
  "randomness_vote":    "22",
  "threshold":          "100"
}

Field	Type	Visibility	Description
balance	u64	private	Voter's token balance
randomness_balance	field	private	Commitment randomness for balance
vote	u64	private	Boolean vote value (0 or 1)
randomness_vote	field	private	Commitment randomness for vote
threshold	u64	public	Minimum balance required to vote

Public inputs

Input	Description
balance_commitment	Poseidon(balance, randomness_balance)
threshold	Public eligibility threshold
vote_commitment	Poseidon(vote, randomness_vote)

note

The current circuit exposes the commitments and threshold as public inputs; it does not expose a nullifier, so double-vote prevention would be enforced by the surrounding contract (e.g. a registry of balance_commitments).