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

Class DelegateFragment

java.lang.Object

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

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

All Implemented Interfaces:

SchnorrFragment

Direct Known Subclasses:

SmallerThanPowerFragment, TwoSidedRangeProof

public abstract class DelegateFragment
extends SendThenDelegateFragment

A SchnorrFragment that sets up some (shared) variables and then runs subprotocols to prove something about these variables.

This is a a special case of a SendThenDelegateFragment in which the SendFirstValue is empty.

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
DelegateFragment()

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 abstract SendThenDelegateFragment.ProverSpec	provideProverSpecWithNoSendFirst(SchnorrVariableAssignment externalWitnesses, SendThenDelegateFragment.ProverSpecBuilder builder) Run by the prover to set up 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 abstract SendThenDelegateFragment.SubprotocolSpec	provideSubprotocolSpec(SendThenDelegateFragment.SubprotocolSpecBuilder builder)
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

DelegateFragment

public DelegateFragment()

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().

provideProverSpecWithNoSendFirst

protected abstract SendThenDelegateFragment.ProverSpec provideProverSpecWithNoSendFirst(SchnorrVariableAssignment externalWitnesses,
                                                                                        SendThenDelegateFragment.ProverSpecBuilder builder)

Run by the prover to set up witness values for variables this fragment proves knowledge of itself (i.e. those specified in DelegateFragment#provideSubprotocolSpec(SubprotocolSpecBuilder)).

A typical example implementation can be found in SmallerThanPowerFragment.

Parameters:

externalWitnesses - the witness values for external variables

builder - helper object to instantiate a ProverSpec

Returns:

the specification of witness values for this fragment's own variables. Returned by 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().

provideSubprotocolSpec

protected abstract SendThenDelegateFragment.SubprotocolSpec provideSubprotocolSpec(SendThenDelegateFragment.SubprotocolSpecBuilder builder)

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