simperby_core/
light_client.rs

1use crate::*;
2use merkle_tree::*;
3use serde::{Deserialize, Serialize};
4
5/// A light client state machine.
6#[derive(Debug, Clone, Serialize, Deserialize)]
7pub struct LightClient {
8    pub repository_roots: Vec<Hash256>,
9    pub commit_roots: Vec<Hash256>,
10    pub height_offset: u64,
11    pub last_header: BlockHeader,
12}
13
14impl LightClient {
15    /// initializes a new light client with the initial header.
16    pub fn new(initial_header: BlockHeader) -> Self {
17        Self {
18            repository_roots: vec![initial_header.repository_merkle_root],
19            commit_roots: vec![initial_header.commit_merkle_root],
20            height_offset: initial_header.height,
21            last_header: initial_header,
22        }
23    }
24
25    /// Updates the header by providing the next block and the proof of it.
26    pub fn update(&mut self, header: BlockHeader, proof: FinalizationProof) -> Result<(), String> {
27        verify::verify_header_to_header(&self.last_header, &header).map_err(|e| e.to_string())?;
28        verify::verify_finalization_proof(&header, &proof).map_err(|e| e.to_string())?;
29        self.repository_roots.push(header.repository_merkle_root);
30        self.commit_roots.push(header.commit_merkle_root);
31        self.last_header = header;
32        Ok(())
33    }
34
35    /// Verifies the given transaction with its proof.
36    pub fn verify_transaction_commitment(
37        &self,
38        transaction: &Transaction,
39        block_height: u64,
40        proof: MerkleProof,
41    ) -> bool {
42        let message = serde_spb::to_vec(transaction).unwrap();
43        if block_height < self.height_offset
44            || block_height >= self.height_offset + self.commit_roots.len() as u64
45        {
46            return false;
47        }
48        proof
49            .verify(
50                self.commit_roots[(block_height - self.height_offset) as usize],
51                &message,
52            )
53            .is_ok()
54    }
55
56    /// Verifies the state entry with its proof.
57    pub fn verify_state_commitment(
58        &self,
59        _message: Vec<u8>,
60        _block_height: u64,
61        _proof: MerkleProof,
62    ) -> bool {
63        todo!()
64    }
65}
simperby_core/light_client.rs

simperby_core/
light_client.rs
