tor_hscrypto/pow/v1/
verify.rs

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1//! Verifier implementation for v1 client puzzles
2
3use crate::pow::err::Error;
4use crate::pow::v1::challenge::Challenge;
5use crate::pow::v1::{err::RuntimeErrorV1, err::SolutionErrorV1, types::Instance, types::Solution};
6use equix::{EquiXBuilder, HashError, RuntimeOption};
7
8use super::Seed;
9
10/// Checker for potential [`Solution`]s to a particular puzzle [`Instance`]
11///
12/// Holds information about the puzzle instance, and optional configuration
13/// settings.
14pub struct Verifier {
15    /// The puzzle instance we're verifying
16    instance: Instance,
17    /// Configuration settings for Equi-X, as an [`EquiXBuilder`] instance
18    equix: EquiXBuilder,
19}
20
21impl Verifier {
22    /// Construct a new [`Verifier`] by wrapping an [`Instance`].
23    pub fn new(instance: Instance) -> Self {
24        Self {
25            instance,
26            equix: Default::default(),
27        }
28    }
29
30    /// Select the HashX runtime to use for this verifier.
31    ///
32    /// By default, uses [`RuntimeOption::TryCompile`]
33    pub fn runtime(&mut self, option: RuntimeOption) -> &mut Self {
34        self.equix.runtime(option);
35        self
36    }
37
38    /// Check whether a solution is valid for this puzzle instance.
39    ///
40    /// May return a [`SolutionErrorV1`] or a [`RuntimeErrorV1`]
41    pub fn check(&self, solution: &Solution) -> Result<(), Error> {
42        match self.check_seed(solution) {
43            Err(e) => Err(Error::BadSolution(e.into())),
44            Ok(()) => {
45                let challenge = Challenge::new(&self.instance, solution.effort(), solution.nonce());
46                match challenge.check_effort(&solution.proof_to_bytes()) {
47                    Err(e) => Err(Error::BadSolution(e.into())),
48                    Ok(()) => match self.equix.verify(challenge.as_ref(), solution.proof()) {
49                        Ok(()) => Ok(()),
50                        Err(equix::Error::HashSum) => {
51                            Err(Error::BadSolution(SolutionErrorV1::HashSum.into()))
52                        }
53                        Err(equix::Error::Hash(HashError::ProgramConstraints)) => Err(
54                            Error::BadSolution(SolutionErrorV1::ChallengeConstraints.into()),
55                        ),
56                        Err(e) => Err(Error::VerifyRuntime(RuntimeErrorV1::EquiX(e).into())),
57                    },
58                }
59            }
60        }
61    }
62
63    /// Check the [`super::SeedHead`] of a solution against an [`Instance`].
64    ///
65    /// This is a very cheap test, this should come first so a service
66    /// can verify every [`Solution`] against its last two [`Instance`]s.
67    fn check_seed(&self, solution: &Solution) -> Result<(), SolutionErrorV1> {
68        if solution.seed_head() == self.instance.seed().head() {
69            Ok(())
70        } else {
71            Err(SolutionErrorV1::Seed)
72        }
73    }
74
75    /// Return the seed for this verifier's instance.
76    pub fn seed(&self) -> &Seed {
77        self.instance.seed()
78    }
79}
tor_hscrypto/pow/v1/verify.rs

tor_hscrypto/pow/v1/
verify.rs
