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| 1 | +use ark_crypto_primitives::merkle_tree::{Config, LeafParam, MerkleTree, MultiPath, TwoToOneParam}; |
| 2 | +use spongefish::{ProofError, ProofResult}; |
| 3 | + |
| 4 | +use crate::{ |
| 5 | + crypto::merkle_tree::proof::FullMultiPath, |
| 6 | + parameters::MerkleProofStrategy, |
| 7 | + whir::utils::{HintDeserialize, HintSerialize}, |
| 8 | +}; |
| 9 | + |
| 10 | +/// Prover-side state for emitting Merkle proofs using a fixed strategy. |
| 11 | +pub struct ProverMerkleState { |
| 12 | + strategy: MerkleProofStrategy, |
| 13 | +} |
| 14 | + |
| 15 | +impl ProverMerkleState { |
| 16 | + pub const fn new(strategy: MerkleProofStrategy) -> Self { |
| 17 | + Self { strategy } |
| 18 | + } |
| 19 | + |
| 20 | + pub fn write_proof_hint<ProverState, MerkleConfig>( |
| 21 | + &self, |
| 22 | + tree: &MerkleTree<MerkleConfig>, |
| 23 | + indices: &[usize], |
| 24 | + prover_state: &mut ProverState, |
| 25 | + ) -> ProofResult<()> |
| 26 | + where |
| 27 | + MerkleConfig: Config, |
| 28 | + ProverState: HintSerialize, |
| 29 | + { |
| 30 | + match self.strategy { |
| 31 | + MerkleProofStrategy::Compressed => { |
| 32 | + let merkle_proof = tree |
| 33 | + .generate_multi_proof(indices.to_vec()) |
| 34 | + .expect("indices sampled from transcript must be valid for the tree"); |
| 35 | + prover_state.hint::<MultiPath<MerkleConfig>>(&merkle_proof)?; |
| 36 | + } |
| 37 | + MerkleProofStrategy::Uncompressed => { |
| 38 | + let proofs = indices |
| 39 | + .iter() |
| 40 | + .map(|&index| { |
| 41 | + tree.generate_proof(index) |
| 42 | + .expect("indices sampled from transcript must be valid for the tree") |
| 43 | + }) |
| 44 | + .collect::<Vec<_>>(); |
| 45 | + let merkle_proof: FullMultiPath<MerkleConfig> = proofs.into(); |
| 46 | + |
| 47 | + prover_state.hint::<FullMultiPath<MerkleConfig>>(&merkle_proof)?; |
| 48 | + } |
| 49 | + } |
| 50 | + |
| 51 | + Ok(()) |
| 52 | + } |
| 53 | +} |
| 54 | + |
| 55 | +/// Verifier-side state for consuming Merkle proofs using a fixed strategy and hash parameters. |
| 56 | +pub struct VerifierMerkleState<'a, MerkleConfig> |
| 57 | +where |
| 58 | + MerkleConfig: Config, |
| 59 | +{ |
| 60 | + strategy: MerkleProofStrategy, |
| 61 | + leaf_hash_params: &'a LeafParam<MerkleConfig>, |
| 62 | + two_to_one_params: &'a TwoToOneParam<MerkleConfig>, |
| 63 | +} |
| 64 | + |
| 65 | +impl<'a, MerkleConfig> VerifierMerkleState<'a, MerkleConfig> |
| 66 | +where |
| 67 | + MerkleConfig: Config, |
| 68 | +{ |
| 69 | + pub const fn new( |
| 70 | + strategy: MerkleProofStrategy, |
| 71 | + leaf_hash_params: &'a LeafParam<MerkleConfig>, |
| 72 | + two_to_one_params: &'a TwoToOneParam<MerkleConfig>, |
| 73 | + ) -> Self { |
| 74 | + Self { |
| 75 | + strategy, |
| 76 | + leaf_hash_params, |
| 77 | + two_to_one_params, |
| 78 | + } |
| 79 | + } |
| 80 | + |
| 81 | + pub fn read_and_verify_proof<VerifierState, L>( |
| 82 | + &self, |
| 83 | + verifier_state: &mut VerifierState, |
| 84 | + indices: &[usize], |
| 85 | + root: &MerkleConfig::InnerDigest, |
| 86 | + leaves: impl IntoIterator<Item = L>, |
| 87 | + ) -> ProofResult<()> |
| 88 | + where |
| 89 | + VerifierState: HintDeserialize, |
| 90 | + L: Clone + std::borrow::Borrow<MerkleConfig::Leaf>, |
| 91 | + { |
| 92 | + let leaves: Vec<L> = leaves.into_iter().collect(); |
| 93 | + |
| 94 | + match self.strategy { |
| 95 | + MerkleProofStrategy::Compressed => { |
| 96 | + let merkle_proof: MultiPath<MerkleConfig> = verifier_state.hint()?; |
| 97 | + if merkle_proof.leaf_indexes != indices { |
| 98 | + return Err(ProofError::InvalidProof); |
| 99 | + } |
| 100 | + |
| 101 | + let correct = merkle_proof |
| 102 | + .verify( |
| 103 | + self.leaf_hash_params, |
| 104 | + self.two_to_one_params, |
| 105 | + root, |
| 106 | + leaves.iter().cloned(), |
| 107 | + ) |
| 108 | + .map_err(|_| ProofError::InvalidProof)?; |
| 109 | + if !correct { |
| 110 | + return Err(ProofError::InvalidProof); |
| 111 | + } |
| 112 | + } |
| 113 | + MerkleProofStrategy::Uncompressed => { |
| 114 | + let merkle_proof: FullMultiPath<MerkleConfig> = verifier_state.hint()?; |
| 115 | + if merkle_proof.indices() != indices { |
| 116 | + return Err(ProofError::InvalidProof); |
| 117 | + } |
| 118 | + |
| 119 | + let correct = merkle_proof |
| 120 | + .verify( |
| 121 | + self.leaf_hash_params, |
| 122 | + self.two_to_one_params, |
| 123 | + root, |
| 124 | + leaves.iter().cloned(), |
| 125 | + ) |
| 126 | + .map_err(|_| ProofError::InvalidProof)?; |
| 127 | + if !correct { |
| 128 | + return Err(ProofError::InvalidProof); |
| 129 | + } |
| 130 | + } |
| 131 | + } |
| 132 | + |
| 133 | + Ok(()) |
| 134 | + } |
| 135 | +} |
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