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

Class SendThenDelegateProtocol

java.lang.Object

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

All Implemented Interfaces:

InteractiveArgument, SigmaProtocol, TwoPartyProtocol

Direct Known Subclasses:

DelegateProtocol

public abstract class SendThenDelegateProtocol
extends java.lang.Object
implements SigmaProtocol

The protocol version of SendThenDelegateFragment.

A SchnorrFragment is always incomplete in the sense that it depends on external variables. In contrast, a SigmaProtocol has no external dependencies and, hence, can be run standalone.

An implementation of a SendThenDelegateProtocol is very similar to an implementation of a SendThenDelegateFragment, except that there are no external SchnorrVariables and the protocol must define all its variables itself.

Field Summary

Fields inherited from interface org.cryptimeleon.craco.protocols.arguments.InteractiveArgument

PROVER_ROLE, VERIFIER_ROLE

Constructor Summary

Constructors

Constructor and Description
SendThenDelegateProtocol()

Method Summary

Modifier and Type	Method and Description
org.cryptimeleon.math.expressions.bool.BooleanExpression	checkTranscriptAsExpression(CommonInput commonInput, Announcement announcement, Challenge challenge, Response response) Used by the verifier to check whether the given transcript is accepting.
org.cryptimeleon.math.serialization.Representation	compressTranscript(CommonInput commonInput, SigmaProtocolTranscript transcript) Returns a compressed (shorter) version of the given transcript.
void	debugProof(CommonInput commonInput, SecretInput secretInput) Checks if commonInput and secretInput are valid inputs for this protocol.
SigmaProtocolTranscript	decompressTranscript(CommonInput commonInput, Challenge challenge, org.cryptimeleon.math.serialization.Representation compressedTranscript) Decompresses a transcript compressed with SigmaProtocol.compressTranscript(CommonInput, SigmaProtocolTranscript)
Announcement	generateAnnouncement(CommonInput commonInput, SecretInput secretInput, AnnouncementSecret announcementSecret) Used by the prover to generate an announcement (the first message sent in the protocol).
AnnouncementSecret	generateAnnouncementSecret(CommonInput commonInput, SecretInput secretInput) Used by the prover to generate a secret value that will be input for future method calls.
Response	generateResponse(CommonInput commonInput, SecretInput secretInput, Announcement announcement, AnnouncementSecret announcementSecret, Challenge challenge) Used by the prover to generate a response (the third and last message sent in the protocol).
SigmaProtocolTranscript	generateSimulatedTranscript(CommonInput commonInput, Challenge challenge) Generates a random transcript with the same distribution as an honestly generated one that contains the given Challenge.
abstract ZnChallengeSpace	getChallengeSpace(CommonInput commonInput) Returns the challenge space used by this protocol.
protected abstract org.cryptimeleon.math.expressions.bool.BooleanExpression	provideAdditionalCheck(CommonInput commonInput, SendFirstValue sendFirstValue)
protected abstract SendThenDelegateFragment.ProverSpec	provideProverSpec(CommonInput commonInput, SecretInput secretInput, 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.SubprotocolSpec	provideSubprotocolSpec(CommonInput commonInput, SendFirstValue sendFirstValue, SendThenDelegateFragment.SubprotocolSpecBuilder builder)
Announcement	restoreAnnouncement(CommonInput commonInput, org.cryptimeleon.math.serialization.Representation repr)
ZnChallenge	restoreChallenge(CommonInput commonInput, org.cryptimeleon.math.serialization.Representation repr)
Response	restoreResponse(CommonInput commonInput, Announcement announcement, Challenge challenge, org.cryptimeleon.math.serialization.Representation repr)
protected abstract SendFirstValue	restoreSendFirstValue(CommonInput commonInput, org.cryptimeleon.math.serialization.Representation repr)
protected abstract SendFirstValue	simulateSendFirstValue(CommonInput commonInput)

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.cryptimeleon.craco.protocols.arguments.sigma.SigmaProtocol

checkTranscript, checkTranscript, generateChallenge, getFirstMessageRole, getProverInstance, getVerifierInstance, instantiateProtocol, restoreTranscript

Methods inherited from interface org.cryptimeleon.craco.protocols.arguments.InteractiveArgument

getRoleNames, instantiateProver, instantiateVerifier

Methods inherited from interface org.cryptimeleon.craco.protocols.TwoPartyProtocol

runProtocolLocally

Constructor Detail

SendThenDelegateProtocol

public SendThenDelegateProtocol()

Method Detail

provideProverSpec

protected abstract SendThenDelegateFragment.ProverSpec provideProverSpec(CommonInput commonInput,
                                                                         SecretInput secretInput,
                                                                         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. those specified in provideSubprotocolSpec(CommonInput, SendFirstValue, SendThenDelegateFragment.SubprotocolSpecBuilder)).

See Also:

SendThenDelegateFragment.provideProverSpec(SchnorrVariableAssignment, SendThenDelegateFragment.ProverSpecBuilder)

restoreSendFirstValue

protected abstract SendFirstValue restoreSendFirstValue(CommonInput commonInput,
                                                        org.cryptimeleon.math.serialization.Representation repr)

simulateSendFirstValue

protected abstract SendFirstValue simulateSendFirstValue(CommonInput commonInput)

See Also:

SendThenDelegateFragment.simulateSendFirstValue()

provideSubprotocolSpec

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

See Also:

SendThenDelegateFragment.provideSubprotocolSpec(SendFirstValue, SendThenDelegateFragment.SubprotocolSpecBuilder)

provideAdditionalCheck

protected abstract org.cryptimeleon.math.expressions.bool.BooleanExpression provideAdditionalCheck(CommonInput commonInput,
                                                                                                   SendFirstValue sendFirstValue)

See Also:

SendThenDelegateFragment.provideAdditionalCheck(SendFirstValue)

getChallengeSpace

public abstract ZnChallengeSpace getChallengeSpace(CommonInput commonInput)

Description copied from interface: SigmaProtocol

Returns the challenge space used by this protocol.

Specified by:

getChallengeSpace in interface SigmaProtocol

generateAnnouncementSecret

public AnnouncementSecret generateAnnouncementSecret(CommonInput commonInput,
                                                     SecretInput secretInput)

Description copied from interface: SigmaProtocol

Used by the prover to generate a secret value that will be input for future method calls.

For example, for an implementation of the original Schnorr protocol, the announcement secret would be a random exponent r.

Specified by:

generateAnnouncementSecret in interface SigmaProtocol

Parameters:

commonInput - input to the overall protocol that both prover and verifier use

secretInput - input to the overall protocol that only the prover gets

Returns:

a secret (internal) value used for generating announcements and responses

generateAnnouncement

public Announcement generateAnnouncement(CommonInput commonInput,
                                         SecretInput secretInput,
                                         AnnouncementSecret announcementSecret)

Description copied from interface: SigmaProtocol

Used by the prover to generate an announcement (the first message sent in the protocol).

Specified by:

generateAnnouncement in interface SigmaProtocol

generateResponse

public Response generateResponse(CommonInput commonInput,
                                 SecretInput secretInput,
                                 Announcement announcement,
                                 AnnouncementSecret announcementSecret,
                                 Challenge challenge)

Description copied from interface: SigmaProtocol

Used by the prover to generate a response (the third and last message sent in the protocol).

Specified by:

generateResponse in interface SigmaProtocol

checkTranscriptAsExpression

public org.cryptimeleon.math.expressions.bool.BooleanExpression checkTranscriptAsExpression(CommonInput commonInput,
                                                                                            Announcement announcement,
                                                                                            Challenge challenge,
                                                                                            Response response)

Description copied from interface: SigmaProtocol

Used by the verifier to check whether the given transcript is accepting. The result is a BooleanExpression, which makes it easier to provide optimization for composed protocols.

Specified by:

checkTranscriptAsExpression in interface SigmaProtocol

Returns:

a BooleanExpression without variables that evaluates to true (for accepting transcripts) or false.

generateSimulatedTranscript

public SigmaProtocolTranscript generateSimulatedTranscript(CommonInput commonInput,
                                                           Challenge challenge)

Description copied from interface: SigmaProtocol

Generates a random transcript with the same distribution as an honestly generated one that contains the given Challenge.

Specified by:

generateSimulatedTranscript in interface SigmaProtocol

restoreAnnouncement

public Announcement restoreAnnouncement(CommonInput commonInput,
                                        org.cryptimeleon.math.serialization.Representation repr)

Specified by:

restoreAnnouncement in interface SigmaProtocol

restoreChallenge

public ZnChallenge restoreChallenge(CommonInput commonInput,
                                    org.cryptimeleon.math.serialization.Representation repr)

Specified by:

restoreChallenge in interface SigmaProtocol

restoreResponse

public Response restoreResponse(CommonInput commonInput,
                                Announcement announcement,
                                Challenge challenge,
                                org.cryptimeleon.math.serialization.Representation repr)

Specified by:

restoreResponse in interface SigmaProtocol

compressTranscript

public org.cryptimeleon.math.serialization.Representation compressTranscript(CommonInput commonInput,
                                                                             SigmaProtocolTranscript transcript)

Description copied from interface: SigmaProtocol

Returns a compressed (shorter) version of the given transcript.

Useful for FiatShamirProofSystem. Compressed transcript does not necessarily contain the challenge (see SigmaProtocol.decompressTranscript(CommonInput, Challenge, Representation))

Specified by:

compressTranscript in interface SigmaProtocol

decompressTranscript

public SigmaProtocolTranscript decompressTranscript(CommonInput commonInput,
                                                    Challenge challenge,
                                                    org.cryptimeleon.math.serialization.Representation compressedTranscript)
                                             throws java.lang.IllegalArgumentException

Description copied from interface: SigmaProtocol

Decompresses a transcript compressed with SigmaProtocol.compressTranscript(CommonInput, SigmaProtocolTranscript)

The guarantee is that if a transcript is valid, then compressing and decompressing yields the same transcript. Additionally, any transcript output by this method is valid (i.e. SigmaProtocol.checkTranscript(CommonInput, SigmaProtocolTranscript) returns true).

Specified by:

decompressTranscript in interface SigmaProtocol

Throws:

java.lang.IllegalArgumentException - is the given compressedTranscript cannot be decompressed into a valid transcript.

debugProof

public void debugProof(CommonInput commonInput,
                       SecretInput secretInput)

Description copied from interface: InteractiveArgument

Checks if commonInput and secretInput are valid inputs for this protocol. Use for debugging. Throws an exception if something is wrong.

Specified by:

debugProof in interface InteractiveArgument