taproot_assets_zk_core/
lib.rs

1#![no_std]
2#![no_main]
3
4extern crate alloc;
5
6/// ZK verification helpers that mirror `taproot-assets-core::verify`.
7pub mod verify;
8
9use bitcoin::TapNodeHash;
10use bitcoin::hashes::Hash;
11use bitcoin::key::TapTweak;
12use bitcoin::secp256k1::{PublicKey as SecpPublicKey, Scalar, Secp256k1};
13use taproot_assets_core::{OpsError, TaprootOps};
14use taproot_assets_types::asset::SerializedKey;
15
16/// A TaprootOps implementation backed by the RISC0 zkVM.
17#[derive(Debug, Clone, Copy, Default)]
18pub struct Risc0TaprootOps;
19
20impl TaprootOps for Risc0TaprootOps {
21    type PubKey = SecpPublicKey;
22
23    fn parse_group_key(&self, key: &SerializedKey) -> Result<Self::PubKey, OpsError> {
24        SecpPublicKey::from_slice(&key.bytes).map_err(|_| OpsError::InvalidRawGroupKey)
25    }
26
27    fn parse_internal_key(&self, key: &SerializedKey) -> Result<Self::PubKey, OpsError> {
28        SecpPublicKey::from_slice(&key.bytes).map_err(|_| OpsError::InvalidInternalKey)
29    }
30
31    fn add_tweak(&self, pubkey: &Self::PubKey, tweak: [u8; 32]) -> Result<Self::PubKey, OpsError> {
32        let secp = Secp256k1::verification_only();
33        let scalar = Scalar::from_be_bytes(tweak).map_err(|_| OpsError::AssetIdTweakOutOfRange)?;
34        pubkey
35            .add_exp_tweak(&secp, &scalar)
36            .map_err(|_| OpsError::InvalidGroupKeyTweak)
37    }
38
39    fn taproot_output_key(
40        &self,
41        internal_key: &Self::PubKey,
42        tapscript_root: Option<[u8; 32]>,
43    ) -> Result<SerializedKey, OpsError> {
44        let secp = Secp256k1::verification_only();
45        let merkle_root = tapscript_root.map(TapNodeHash::from_byte_array);
46        let (xonly_key, _) = internal_key.x_only_public_key();
47        let (tweaked, parity) = xonly_key.tap_tweak(&secp, merkle_root);
48        let output_key =
49            SecpPublicKey::from_x_only_public_key(tweaked.to_x_only_public_key(), parity);
50
51        Ok(SerializedKey {
52            bytes: output_key.serialize(),
53        })
54    }
55}
taproot_assets_zk_core/lib.rs

taproot_assets_zk_core/
lib.rs
