arcium-primitives 0.4.5

Arcium primitives
Documentation 
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use hybrid_array::Array;
use rand::SeedableRng;
use serde::{Deserialize, Serialize};
use zeroize::Zeroize;

use super::Transcript;
use crate::{
    constants::CollisionResistanceBytes,
    hashing::{flatten_slices_with_length_prefixes, hash},
    random::{BaseRng, Seed},
    types::{identifiers::ProtocolInfo, SessionId},
};

#[derive(Clone, Default, Debug, Serialize, Deserialize, Zeroize)]
pub struct FolkloreTranscript {
    state: Array<u8, CollisionResistanceBytes>,
}

impl Transcript for FolkloreTranscript {
    type Rng = BaseRng;

    fn new(protocol_info: &'static ProtocolInfo, session_id: &SessionId) -> Self {
        let state = hash(&[protocol_info.tag(), session_id.as_ref()]);
        Self { state }
    }

    fn append_with<T: AsRef<[u8]>>(&mut self, label: &'static [u8], value: &T) {
        self.state = hash(&[label, value.as_ref(), self.state.as_ref()]);
    }

    fn append_many_with<T: AsRef<[u8]>>(&mut self, label: &'static [u8], values: &[T]) {
        let concatenated = flatten_slices_with_length_prefixes(values);
        let values_len = (values.len() as u64).to_le_bytes();
        self.state = hash(&[label, &concatenated, self.state.as_ref(), &values_len]);
    }

    fn extract(&mut self, label: &'static [u8]) -> Seed {
        self.state = hash(&[label, self.state.as_ref()]);
        *self.state.as_ref()
    }

    fn extract_rng(&mut self, label: &'static [u8]) -> Self::Rng {
        self.state = hash(&[label, self.state.as_ref()]);
        BaseRng::from_seed(self.state.into())
    }
}