org.cryptimeleon.craco.protocols.arguments.sigma.schnorr.setmembership

Class SetMembershipFragment

java.lang.Object

org.cryptimeleon.craco.protocols.arguments.sigma.schnorr.SendThenDelegateFragment

org.cryptimeleon.craco.protocols.arguments.sigma.schnorr.setmembership.SetMembershipFragment

All Implemented Interfaces:

SchnorrFragment

public class SetMembershipFragment
extends SendThenDelegateFragment

A fragment to prove that a given variable is in a set of allowed values.

Nested Class Summary

Nested classes/interfaces inherited from class org.cryptimeleon.craco.protocols.arguments.sigma.schnorr.SendThenDelegateFragment

SendThenDelegateFragment.ProverSpec, SendThenDelegateFragment.ProverSpecBuilder, SendThenDelegateFragment.SendThenDelegateAnnouncement, SendThenDelegateFragment.SubprotocolSpec, SendThenDelegateFragment.SubprotocolSpecBuilder, SendThenDelegateFragment.WitnessValues

Constructor Summary

Constructors

Constructor and Description
SetMembershipFragment(SetMembershipPublicParameters pp, org.cryptimeleon.math.expressions.exponent.ExponentExpr member) Instantiates the fragment.

Method Summary

Modifier and Type	Method and Description
protected org.cryptimeleon.math.expressions.bool.BooleanExpression	provideAdditionalCheck(SendFirstValue sendFirstValue) Runs an additional check on the sendFirstValue when the verifier checks a transcript.
protected SendThenDelegateFragment.ProverSpec	provideProverSpec(SchnorrVariableAssignment externalWitnesses, SendThenDelegateFragment.ProverSpecBuilder builder) Run by the prover to set up (1) the sendFirstValue and (2) witness values for variables this fragment proves knowledge of itself (i.e.
protected SendThenDelegateFragment.SubprotocolSpec	provideSubprotocolSpec(SendFirstValue sendFirstValue, SendThenDelegateFragment.SubprotocolSpecBuilder builder) Run by both prover and verifier to deterministically instantiate the desired subprotocols (subfragments) depending on the sendFirstValue. For this, the given SendThenDelegateFragment.SubprotocolSpecBuilder allows you to create (1) variables (witnesses) and (2) register fragments to run.
protected SendFirstValue	restoreSendFirstValue(org.cryptimeleon.math.serialization.Representation repr) Restores a SendFirstValue from Representation
protected SendFirstValue	simulateSendFirstValue() Returns a random SendFirstValue with the same probability distribution as an honest prover would generate.

Methods inherited from class org.cryptimeleon.craco.protocols.arguments.sigma.schnorr.SendThenDelegateFragment

checkTranscript, compressTranscript, debugFragment, decompressTranscript, generateAnnouncement, generateAnnouncementSecret, generateResponse, generateSimulatedTranscript, restoreAnnouncement, restoreResponse

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

SetMembershipFragment

public SetMembershipFragment(SetMembershipPublicParameters pp,
                             org.cryptimeleon.math.expressions.exponent.ExponentExpr member)

Instantiates the fragment.

Parameters:

pp - public parameters to use (implicitly defines the set for which membership is proven, see SetMembershipPublicParameters).

member - an expression whose value shall be in the set. In the easiest case, this is a SchnorrZnVariable, but it can be any affine linear combination of SchnorrZnVariables

Method Detail

provideProverSpec

protected SendThenDelegateFragment.ProverSpec provideProverSpec(SchnorrVariableAssignment externalWitnesses,
                                                                SendThenDelegateFragment.ProverSpecBuilder builder)

Description copied from class: SendThenDelegateFragment

Run by the prover to set up (1) the sendFirstValue and (2) witness values for variables this fragment proves knowledge of itself (i.e. those specified in SendThenDelegateFragment.provideSubprotocolSpec(SendFirstValue, SubprotocolSpecBuilder)).

A typical example implementation can be found in SetMembershipFragment.

Specified by:

provideProverSpec in class SendThenDelegateFragment

Parameters:

externalWitnesses - the witness values for external variables

builder - helper object to instantiate a SendThenDelegateFragment.ProverSpec

Returns:

the specification of sendFirstValue and witness values for this fragment's own variables. Returned by SendThenDelegateFragment.ProverSpecBuilder.build().

restoreSendFirstValue

protected SendFirstValue restoreSendFirstValue(org.cryptimeleon.math.serialization.Representation repr)

Description copied from class: SendThenDelegateFragment

Restores a SendFirstValue from Representation

Specified by:

restoreSendFirstValue in class SendThenDelegateFragment

simulateSendFirstValue

protected SendFirstValue simulateSendFirstValue()

Description copied from class: SendThenDelegateFragment

Returns a random SendFirstValue with the same probability distribution as an honest prover would generate.

Specified by:

simulateSendFirstValue in class SendThenDelegateFragment

provideSubprotocolSpec

protected SendThenDelegateFragment.SubprotocolSpec provideSubprotocolSpec(SendFirstValue sendFirstValue,
                                                                          SendThenDelegateFragment.SubprotocolSpecBuilder builder)

Description copied from class: SendThenDelegateFragment

Run by both prover and verifier to deterministically instantiate the desired subprotocols (subfragments) depending on the sendFirstValue.
For this, the given SendThenDelegateFragment.SubprotocolSpecBuilder allows you to create (1) variables (witnesses) and (2) register fragments to run. The SendThenDelegateFragment will then take care of proving knowledge of the desired witnesses and running the desired subfragments. For the subfragments, the registered variables will be considered "external" (cf. SchnorrFragment).

A typical example implementation can be found in SetMembershipFragment.

Specified by:

provideSubprotocolSpec in class SendThenDelegateFragment

Parameters:

sendFirstValue - the value the prover sends as his first message.

builder - helper object to instantiate a SendThenDelegateFragment.SubprotocolSpec

Returns:

the specification of what variables to prove knowledge of and what subfragments to run (for which these variables will be "external"). Returned by SendThenDelegateFragment.SubprotocolSpecBuilder.build().

provideAdditionalCheck

protected org.cryptimeleon.math.expressions.bool.BooleanExpression provideAdditionalCheck(SendFirstValue sendFirstValue)

Description copied from class: SendThenDelegateFragment

Runs an additional check on the sendFirstValue when the verifier checks a transcript.

Specified by:

provideAdditionalCheck in class SendThenDelegateFragment