Struct VerifiableQueryResult

pub struct VerifiableQueryResult<CP: CommitmentEvaluationProof> {
    pub provable_result: Option<ProvableQueryResult>,
    pub proof: Option<QueryProof<CP>>,
}

The result of an sql query along with a proof that the query is valid. The result and proof can be verified using commitments to database columns.

Note: the query result is stored in an intermediate form rather than the final form the end-user sees. The final form is obtained after verification. Using an intermediate form allows us to handle overflow and certain cases where the final result might use floating point numbers (e.g. SELECT STDDEV(A) FROM T WHERE B = 0).

Below we demonstrate typical usage of VerifiableQueryResult with pseudo-code.

Here we assume that a verifier only has access to the commitments of database columns. To process a query, the verifier forwards the query to an untrusted prover. The prover has full access to the database and constructs a VerifiableQueryResult that it sends back to the verifier. The verifier checks that the result is valid using its commitments, and constructs the finalized form of the query result.

prover_process_query(database_accessor) {
      query <- receive_query_from_verifier()

      verifiable_result <- VerifiableQueryResult::new(query, database_accessor)
            // When we construct VerifiableQueryResult from a query expression, we compute
            // both the result of the query in intermediate form and the proof of the result
            // at the same time.

      send_to_verifier(verifiable_result)
}

verifier_process_query(query, commitment_accessor) {
   verifiable_result <- send_query_to_prover(query)

   verify_result <- verifiable_result.verify(query, commitment_accessor)
   if verify_result.is_error() {
        // The prover did something wrong. Perhaps the prover tried to tamper with the query
        // result or maybe its version of the database was out-of-sync with the verifier's
        // version.
        do_verification_error()
   }

   query_result <- verify_result.query_result()
   if query_result.is_error() {
        // The prover processed the query correctly, but the query resulted in an error.
        // For example, perhaps the query added two 64-bit integer columns together that
        // resulted in an overflow.
        do_query_error()
   }

   do_query_success(query_result)
        // The prover correctly processed a query and the query succeeded. Now, we can
        // proceed to use the result.
}

Note: Because the class is deserialized from untrusted data, it cannot maintain any invariant on its data members; hence, they are all public so as to allow for easy manipulation for testing.

Fields

provable_result: Option<ProvableQueryResult>

The result of the query in intermediate form.

proof: Option<QueryProof<CP>>

The proof that the query result is valid.

Implementations

impl<CP: CommitmentEvaluationProof> VerifiableQueryResult<CP>

pub fn new( expr: &(impl ProofPlan<CP::Commitment> + Serialize), accessor: &impl DataAccessor<CP::Scalar>, setup: &CP::ProverPublicSetup<'_>, ) -> Self

Form a VerifiableQueryResult from a query expression.

This function both computes the result of a query and constructs a proof of the results validity.

pub fn verify( &self, expr: &(impl ProofPlan<CP::Commitment> + Serialize), accessor: &impl CommitmentAccessor<CP::Commitment>, setup: &CP::VerifierPublicSetup<'_>, ) -> QueryResult<CP::Scalar>

Verify a VerifiableQueryResult. Upon success, this function returns the finalized form of the query result.

Note: a verified result can still respresent an error (e.g. overflow), but it is a verified error.

Note: This does NOT transform the result!

Trait Implementations

impl<CP: Clone + CommitmentEvaluationProof> Clone for VerifiableQueryResult<CP>

fn clone(&self) -> VerifiableQueryResult<CP>

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<CP: Default + CommitmentEvaluationProof> Default for VerifiableQueryResult<CP>

fn default() -> VerifiableQueryResult<CP>

Returns the “default value” for a type.

impl<'de, CP> Deserialize<'de> for VerifiableQueryResult<CP>

where CP: Deserialize<'de> + CommitmentEvaluationProof,

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl<CP> Serialize for VerifiableQueryResult<CP>

where CP: Serialize + CommitmentEvaluationProof,

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.