halo2/src/constants.rs

//! Constants used in the Orchard protocol.

/// $\ell^\mathsf{Orchard}_\mathsf{base}$
pub(crate) const L_ORCHARD_BASE: usize = 255;

// SWU hash-to-curve personalizations

/// SWU hash-to-curve personalization
/// This is used for the spending key base point and the nullifier base point K^Orchard
pub const ORCHARD_PERSONALIZATION: &str = "z.cash:Orchard";

/// SWU hash-to-curve personalization for the group hash for key diversification
pub const KEY_DIVERSIFICATION_PERSONALIZATION: &str = "z.cash:Orchard-gd";

/// SWU hash-to-curve personalization for the value commitment generator
pub const VALUE_COMMITMENT_PERSONALIZATION: &str = "z.cash:Orchard-cv";

/// SWU hash-to-curve personalization for the note commitment generator
pub const NOTE_COMMITMENT_PERSONALIZATION: &str = "z.cash:Orchard-NoteCommit";

/// SWU hash-to-curve personalization for the IVK commitment generator
pub const COMMIT_IVK_PERSONALIZATION: &str = "z.cash:Orchard-CommitIvk";

/// SWU hash-to-curve personalization for the Merkle CRH generator
pub const MERKLE_CRH_PERSONALIZATION: &str = "z.cash:Orchard-MerkleCRH";

/// Window size for fixed-base scalar multiplication
pub const FIXED_BASE_WINDOW_SIZE: usize = 3;