> For the complete documentation index, see [llms.txt](https://valargroup.gitbook.io/shielded-vote-docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://valargroup.gitbook.io/shielded-vote-docs/circuit-components/overview.md). # Overview The three ZKPs in Shielded Vote are built from reusable circuit components (gadgets). Many are adapted from the Orchard circuit specification; others are new to the governance protocol. ## Components from Orchard (reused or adapted) | Component | Used in | Notes | | ------------------------------------------------------------------------------------------------------------------------------------------------------------- | -------------- | ---------------------------------------------------------- | | [Note Commitment Integrity](https://github.com/z-cale/shielded-vote-book/blob/main/circuits/shielded_vote_book/circuits/note-commitment-integrity.md) | ZKP #1 | Standard Orchard NoteCommit | | [Nullifier Derivation](https://github.com/z-cale/shielded-vote-book/blob/main/circuits/shielded_vote_book/circuits/nullifier-derivation.md) | ZKP #1 | Standard Orchard DeriveNullifier | | [Merkle Tree Membership](https://github.com/z-cale/shielded-vote-book/blob/main/circuits/shielded_vote_book/circuits/merkle-tree-membership.md) | ZKP #1, #2, #3 | Adapted to use Poseidon; conditional skip for padded notes | | [Diversified Address Integrity](https://github.com/z-cale/shielded-vote-book/blob/main/circuits/shielded_vote_book/circuits/diversified-address-integrity.md) | ZKP #1 | Standard Orchard ivk check | | [Spend Authority](https://github.com/z-cale/shielded-vote-book/blob/main/circuits/shielded_vote_book/circuits/spend-authority.md) | ZKP #1, #2 | Standard SpendAuthSig rerandomization | ## New components | Component | Used in | Notes | | ------------------------------------------------------------------------------------------------------------------------------------------------------------- | -------------- | ----------------------------------------------------------- | | [Rho Binding](https://github.com/z-cale/shielded-vote-book/blob/main/circuits/shielded_vote_book/circuits/rho-binding.md) | ZKP #1 | Binds signed note to delegated notes and round | | [Governance Nullifier](https://github.com/z-cale/shielded-vote-book/blob/main/circuits/shielded_vote_book/circuits/governance-nullifier.md) | ZKP #1 | Domain-separated nullifier for double-delegation prevention | | [VAN Nullifier](https://github.com/z-cale/shielded-vote-book/blob/main/circuits/shielded_vote_book/circuits/van-nullifier.md) | ZKP #2 | Nullifier for Vote Authority Notes | | [Share Nullifier](https://github.com/z-cale/shielded-vote-book/blob/main/circuits/shielded_vote_book/circuits/share-nullifier.md) | ZKP #3 | Nullifier for individual vote shares | | [Proposal Authority Decrement](https://github.com/z-cale/shielded-vote-book/blob/main/circuits/shielded_vote_book/circuits/proposal-authority-decrement.md) | ZKP #2 | Bitmask decrement for proposal permissions | | [Shares Range Check](https://github.com/z-cale/shielded-vote-book/blob/main/circuits/shielded_vote_book/circuits/shares-range-check.md) | ZKP #2 | Range proof for each share value | | [El Gamal Encryption Integrity](https://github.com/z-cale/shielded-vote-book/blob/main/circuits/shielded_vote_book/circuits/el-gamal-encryption-integrity.md) | ZKP #2 | Proves valid El Gamal ciphertext construction | | [Shares Hash Integrity](https://github.com/z-cale/shielded-vote-book/blob/main/circuits/shielded_vote_book/circuits/shares-hash-integrity.md) | ZKP #2, #3 | Flat hash over 16 encrypted shares | | [Vote Commitment Integrity](https://github.com/z-cale/shielded-vote-book/blob/main/circuits/shielded_vote_book/circuits/vote-commitment-integrity.md) | ZKP #2, #3 | Hash of domain tag + shares hash + proposal + decision | | [Domain Tag Separation](https://github.com/z-cale/shielded-vote-book/blob/main/circuits/shielded_vote_book/circuits/domain-tag-separation.md) | ZKP #1, #2, #3 | Prevents VAN/VC collision in shared tree | ## Infrastructure | Component | Used in | Notes | | --------------------------------------------------------------------------------------------------------------------------------------- | ------- | ------------------------------------------------------------------ | | [Poseidon Hash](https://github.com/z-cale/shielded-vote-book/blob/main/circuits/shielded_vote_book/circuits/poseidon-hash.md) | All | Used throughout for commitments, nullifiers, and Merkle tree nodes | | [IMT Non-Membership](https://github.com/z-cale/shielded-vote-book/blob/main/circuits/shielded_vote_book/circuits/imt-non-membership.md) | ZKP #1 | Exclusion proof against the nullifier IMT | | [Ballot Scaling](https://github.com/z-cale/shielded-vote-book/blob/main/circuits/shielded_vote_book/circuits/ballot-scaling.md) | ZKP #1 | Floor-division of zatoshi balance into ballot count | ## Implementation note: range checks via 10-bit lookup All range checks in the circuit use a **10-bit lookup table** (`LookupRangeCheckConfig`), which decomposes a value into 10-bit words. This means the table can only directly enforce bit-widths that are multiples of 10 (10, 20, 30, …). To enforce an exact N-bit range where N is not a multiple of 10, the circuit **pre-multiplies the value by `2^(k - N)`** (where `k` is the smallest multiple of 10 ≥ N) before passing it to the range check. This left-shift ensures any value ≥ 2^N overflows the k-bit window and fails the lookup. For example, to check that `x < 2^26`: 1. Compute `x_shifted = x * 2^4` (since 30 is the next multiple of 10 above 26) 2. Range-check `x_shifted` with 3 words × 10 bits = 30 bits If `x ≥ 2^26`, then `x * 2^4 ≥ 2^30`, which exceeds the 30-bit range and fails. This pattern is used in [Ballot Scaling](https://github.com/z-cale/shielded-vote-book/blob/main/circuits/shielded_vote_book/circuits/ballot-scaling.md) and [Shares Range Check](https://github.com/z-cale/shielded-vote-book/blob/main/circuits/shielded_vote_book/circuits/shares-range-check.md).