subspace_proof_of_time/
lib.rs

1//! Proof of time implementation.
2
3#![feature(portable_simd)]
4#![no_std]
5
6mod aes;
7
8use core::num::NonZeroU32;
9use subspace_core_primitives::pot::{PotCheckpoints, PotSeed};
10
11/// Proof of time error
12#[derive(Debug, thiserror::Error)]
13pub enum PotError {
14    /// Iterations are not multiple of number of checkpoints times two
15    #[error(
16        "Iterations {iterations} are not multiple of number of checkpoints {num_checkpoints} \
17        times two"
18    )]
19    NotMultipleOfCheckpoints {
20        /// Slot iterations provided
21        iterations: NonZeroU32,
22        /// Number of checkpoints
23        num_checkpoints: u32,
24    },
25}
26
27/// Run PoT proving and produce checkpoints.
28///
29/// Returns error if `iterations` is not a multiple of checkpoints times two.
30pub fn prove(seed: PotSeed, iterations: NonZeroU32) -> Result<PotCheckpoints, PotError> {
31    if !iterations
32        .get()
33        .is_multiple_of(u32::from(PotCheckpoints::NUM_CHECKPOINTS.get() * 2))
34    {
35        return Err(PotError::NotMultipleOfCheckpoints {
36            iterations,
37            num_checkpoints: u32::from(PotCheckpoints::NUM_CHECKPOINTS.get()),
38        });
39    }
40
41    Ok(aes::create(
42        seed,
43        seed.key(),
44        iterations.get() / u32::from(PotCheckpoints::NUM_CHECKPOINTS.get()),
45    ))
46}
47
48/// Verify checkpoint, number of iterations is set across uniformly distributed checkpoints.
49///
50/// Returns error if `iterations` is not a multiple of checkpoints times two.
51pub fn verify(
52    seed: PotSeed,
53    iterations: NonZeroU32,
54    checkpoints: &PotCheckpoints,
55) -> Result<bool, PotError> {
56    let num_checkpoints = checkpoints.len() as u32;
57    if !iterations.get().is_multiple_of(num_checkpoints * 2) {
58        return Err(PotError::NotMultipleOfCheckpoints {
59            iterations,
60            num_checkpoints,
61        });
62    }
63
64    Ok(aes::verify_sequential(
65        seed,
66        seed.key(),
67        checkpoints,
68        iterations.get() / num_checkpoints,
69    ))
70}
subspace_proof_of_time/lib.rs

subspace_proof_of_time/
lib.rs
