Trait VerificationPredicates 

pub trait VerificationPredicates: Send + Sync {
    type Sha256: MerkleHash + Sha256 + Default;

    // Provided methods
    fn validator_sets_match(
        &self,
        validators: &ValidatorSet,
        header_validators_hash: Hash,
    ) -> Result<(), VerificationError> { ... }
    fn next_validators_match(
        &self,
        next_validators: &ValidatorSet,
        header_next_validators_hash: Hash,
    ) -> Result<(), VerificationError> { ... }
    fn header_matches_commit(
        &self,
        header: &Header,
        commit_hash: Hash,
    ) -> Result<(), VerificationError> { ... }
    fn valid_commit(
        &self,
        signed_header: &SignedHeader,
        validators: &ValidatorSet,
        commit_validator: &dyn CommitValidator,
    ) -> Result<(), VerificationError> { ... }
    fn is_within_trust_period(
        &self,
        trusted_header_time: Time,
        trusting_period: Duration,
        now: Time,
    ) -> Result<(), VerificationError> { ... }
    fn is_header_from_past(
        &self,
        untrusted_header_time: Time,
        clock_drift: Duration,
        now: Time,
    ) -> Result<(), VerificationError> { ... }
    fn is_monotonic_bft_time(
        &self,
        untrusted_header_time: Time,
        trusted_header_time: Time,
    ) -> Result<(), VerificationError> { ... }
    fn is_monotonic_height(
        &self,
        untrusted_height: Height,
        trusted_height: Height,
    ) -> Result<(), VerificationError> { ... }
    fn is_matching_chain_id(
        &self,
        untrusted_chain_id: &ChainId,
        trusted_chain_id: &ChainId,
    ) -> Result<(), VerificationError> { ... }
    fn has_sufficient_validators_and_signers_overlap(
        &self,
        untrusted_sh: &SignedHeader,
        trusted_validators: &ValidatorSet,
        trust_threshold: &TrustThreshold,
        untrusted_validators: &ValidatorSet,
        calculator: &dyn VotingPowerCalculator,
    ) -> Result<(), VerificationError> { ... }
    fn has_sufficient_signers_overlap(
        &self,
        untrusted_sh: &SignedHeader,
        untrusted_validators: &ValidatorSet,
        calculator: &dyn VotingPowerCalculator,
    ) -> Result<(), VerificationError> { ... }
    fn valid_next_validator_set(
        &self,
        untrusted_validators_hash: Hash,
        trusted_next_validators_hash: Hash,
    ) -> Result<(), VerificationError> { ... }
}

Defines the various predicates used to validate and verify light blocks.

A default, spec abiding implementation is provided for each method.

This enables test implementations to only override a single method rather than have to re-define every predicate.

Required Associated Types

type Sha256: MerkleHash + Sha256 + Default

The implementation of SHA256 digest

Provided Methods

fn validator_sets_match( &self, validators: &ValidatorSet, header_validators_hash: Hash, ) -> Result<(), VerificationError>

Compare the provided validator_set_hash against the hash produced from hashing the validator set.

fn next_validators_match( &self, next_validators: &ValidatorSet, header_next_validators_hash: Hash, ) -> Result<(), VerificationError>

Check that the hash of the next validator set in the header match the actual one.

fn header_matches_commit( &self, header: &Header, commit_hash: Hash, ) -> Result<(), VerificationError>

Check that the hash of the header in the commit matches the actual one.

fn valid_commit( &self, signed_header: &SignedHeader, validators: &ValidatorSet, commit_validator: &dyn CommitValidator, ) -> Result<(), VerificationError>

Validate the commit using the given commit validator.

fn is_within_trust_period( &self, trusted_header_time: Time, trusting_period: Duration, now: Time, ) -> Result<(), VerificationError>

Check that the trusted header is within the trusting period, adjusting for clock drift.

fn is_header_from_past( &self, untrusted_header_time: Time, clock_drift: Duration, now: Time, ) -> Result<(), VerificationError>

Check that the untrusted header is from past.

fn is_monotonic_bft_time( &self, untrusted_header_time: Time, trusted_header_time: Time, ) -> Result<(), VerificationError>

Check that time passed monotonically between the trusted header and the untrusted one.

fn is_monotonic_height( &self, untrusted_height: Height, trusted_height: Height, ) -> Result<(), VerificationError>

Check that the height increased between the trusted header and the untrusted one.

fn is_matching_chain_id( &self, untrusted_chain_id: &ChainId, trusted_chain_id: &ChainId, ) -> Result<(), VerificationError>

Check that the chain-ids of the trusted header and the untrusted one are the same

fn has_sufficient_validators_and_signers_overlap( &self, untrusted_sh: &SignedHeader, trusted_validators: &ValidatorSet, trust_threshold: &TrustThreshold, untrusted_validators: &ValidatorSet, calculator: &dyn VotingPowerCalculator, ) -> Result<(), VerificationError>

Checks that there is enough overlap between validators and the untrusted signed header.

First of all, checks that enough validators from the trusted_validators set signed the untrusted header to reach given trust_threshold.

Second of all, checks that enough validators from the untrusted_validators set signed the untrusted header to reach a trust threshold of ⅔.

If both of those conditions aren’t met, it’s unspecified which error is returned.

Note also that the method isn’t guaranteed to verify all the signatures present in the signed header. If there are invalid signatures, the method may or may not return an error depending on which validators those signatures correspond to.

fn has_sufficient_signers_overlap( &self, untrusted_sh: &SignedHeader, untrusted_validators: &ValidatorSet, calculator: &dyn VotingPowerCalculator, ) -> Result<(), VerificationError>

Check that there is enough signers overlap between the given, untrusted validator set and the untrusted signed header.

fn valid_next_validator_set( &self, untrusted_validators_hash: Hash, trusted_next_validators_hash: Hash, ) -> Result<(), VerificationError>

Check that the hash of the next validator set in the trusted block matches the hash of the validator set in the untrusted one.

Implementors

impl VerificationPredicates for ProdPredicates

Available on crate feature rust-crypto only.

type Sha256 = CoreWrapper<CtVariableCoreWrapper<Sha256VarCore, UInt<UInt<UInt<UInt<UInt<UInt<UTerm, B1>, B0>, B0>, B0>, B0>, B0>, OidSha256>>