coconut-crypto 0.14.0

Threshold anonymous credentials based on the paper https://eprint.iacr.org/2022/011
Documentation 
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use secret_sharing_and_dkg::common::ParticipantId;

use crate::helpers::{IndexIsOutOfBounds, InvalidPair};

/// An error originated from `Signature`.
#[derive(Debug, Clone, PartialEq, Eq)]
pub enum PSError {
    NoMessages,
    InvalidMessageCount { received: usize, expected: usize },
    MessageIndicesMustBeUniqueAndSorted(InvalidPair<usize>),
    ZeroSignature,
    MessageIndexIsOutOfBounds(IndexIsOutOfBounds),
    PairingCheckFailed,
}

impl From<IndexIsOutOfBounds> for PSError {
    fn from(err: IndexIsOutOfBounds) -> Self {
        Self::MessageIndexIsOutOfBounds(err)
    }
}

impl From<InvalidPair<usize>> for PSError {
    fn from(err: InvalidPair<usize>) -> Self {
        Self::MessageIndicesMustBeUniqueAndSorted(err)
    }
}

/// An error originated from `BlindSignature`.
#[derive(Debug, Clone, PartialEq, Eq)]
pub enum BlindPSError {
    NoCommitmentsOrMessages,
    IndexIsOutOfBounds(IndexIsOutOfBounds),
    InvalidCommitmentsAndMessagesCount {
        received: Option<usize>,
        expected: usize,
    },
    BlindingIndicesMustBeUniqueAndSorted(InvalidPair<usize>),
    IncompatibleVerificationKey,
    // The h given by signer is not the same as generated by the user. It was generated by hashing the
    // commitment to all messages, i.e. result of query `(ro.query.ini,sid,com)` from the paper
    InvalidH,
}

impl From<IndexIsOutOfBounds> for BlindPSError {
    fn from(err: IndexIsOutOfBounds) -> Self {
        Self::IndexIsOutOfBounds(err)
    }
}

impl From<InvalidPair<usize>> for BlindPSError {
    fn from(err: InvalidPair<usize>) -> Self {
        Self::BlindingIndicesMustBeUniqueAndSorted(err)
    }
}

/// An error originated from `AggregatedSignature`.
#[derive(Debug, Clone, PartialEq, Eq)]
pub enum AggregatedPSError {
    NoSignatures,
    InvalidSigma1For(ParticipantId),
    ParticipantIdsMustBeUniqueAndSorted(InvalidPair<ParticipantId>),
    PSError(PSError),
    ParticipantIdCantBeZero,
}

impl From<InvalidPair<ParticipantId>> for AggregatedPSError {
    fn from(err: InvalidPair<ParticipantId>) -> Self {
        Self::ParticipantIdsMustBeUniqueAndSorted(err)
    }
}

impl From<PSError> for AggregatedPSError {
    fn from(error: PSError) -> Self {
        Self::PSError(error)
    }
}