ab_proof_of_time/
lib.rs

1//! Proof of time implementation.
2
3#![cfg_attr(target_arch = "aarch64", feature(array_chunks))]
4#![feature(portable_simd)]
5#![no_std]
6
7mod aes;
8
9use ab_core_primitives::pot::{PotCheckpoints, PotSeed};
10use core::num::NonZeroU32;
11
12/// Proof of time error
13#[derive(Debug, thiserror::Error)]
14pub enum PotError {
15    /// Iterations are not multiple of number of checkpoints times two
16    #[error(
17        "Iterations {iterations} are not multiple of number of checkpoints {num_checkpoints} \
18        times two"
19    )]
20    NotMultipleOfCheckpoints {
21        /// Slot iterations provided
22        iterations: NonZeroU32,
23        /// Number of checkpoints
24        num_checkpoints: u32,
25    },
26}
27
28/// Run PoT proving and produce checkpoints.
29///
30/// Returns error if `iterations` is not a multiple of checkpoints times two.
31#[cfg_attr(feature = "no-panic", no_panic::no_panic)]
32pub fn prove(seed: PotSeed, iterations: NonZeroU32) -> Result<PotCheckpoints, PotError> {
33    if iterations.get() % u32::from(PotCheckpoints::NUM_CHECKPOINTS.get() * 2) != 0 {
34        return Err(PotError::NotMultipleOfCheckpoints {
35            iterations,
36            num_checkpoints: u32::from(PotCheckpoints::NUM_CHECKPOINTS.get()),
37        });
38    }
39
40    // TODO: Is there a point in having both values derived from the same source?
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.
51// TODO: Figure out what is wrong with macOS here
52#[cfg_attr(
53    all(feature = "no-panic", not(target_os = "macos")),
54    no_panic::no_panic
55)]
56pub fn verify(
57    seed: PotSeed,
58    iterations: NonZeroU32,
59    checkpoints: &PotCheckpoints,
60) -> Result<bool, PotError> {
61    let num_checkpoints = checkpoints.len() as u32;
62    if iterations.get() % (num_checkpoints * 2) != 0 {
63        return Err(PotError::NotMultipleOfCheckpoints {
64            iterations,
65            num_checkpoints,
66        });
67    }
68
69    Ok(aes::verify_sequential(
70        seed,
71        seed.key(),
72        checkpoints,
73        iterations.get() / num_checkpoints,
74    ))
75}
ab_proof_of_time/lib.rs

ab_proof_of_time/
lib.rs
