org.cryptimeleon.craco.accumulator

Interface AccumulatorScheme<AccumulatedType extends org.cryptimeleon.math.serialization.Representable>

Type Parameters:

AccumulatedType - the type of values that can be accumulated with this scheme.

All Superinterfaces:

org.cryptimeleon.math.serialization.Representable, org.cryptimeleon.math.serialization.annotations.RepresentationRestorer, org.cryptimeleon.math.serialization.StandaloneRepresentable

All Known Implementing Classes:

NguyenAccumulatorScheme

public interface AccumulatorScheme<AccumulatedType extends org.cryptimeleon.math.serialization.Representable>
extends org.cryptimeleon.math.serialization.StandaloneRepresentable, org.cryptimeleon.math.serialization.annotations.RepresentationRestorer

An accumulator scheme is essentially a hash function that takes a set of values and creates a short digest for this set. One can compute witnesses for elements included in the digest, which enables fast verification of set membership.

Method Summary

Modifier and Type	Method and Description
AccumulatorDigest	createDigest(java.util.Collection<? extends AccumulatedType> setOfValues) Creates the accumulator for the given set of values (essentially a collision-resistant hash of setOfValues).
AccumulatorWitness	createWitness(AccumulatorDigest digest, java.util.Collection<? extends AccumulatedType> setOfAccumulatedValues, AccumulatedType valueToComputeWitnessFor) Creates a short witness that can be used to verify set membership in an accumulator.
default AccumulatorDigest	delete(AccumulatorDigest digest, java.util.Collection<? extends AccumulatedType> setOfValues, AccumulatedType valueToDelete) Given an accumulator for setOfValues, computes an accumulator for setOfValues \ {additionalValue}.
java.lang.Integer	getMaxNumAccumulatedValues() Returns maximum number of AccumulatedTypes that can be simultaneously accumulated in the Accumulator or null if unbounded.
default AccumulatorDigest	insert(AccumulatorDigest digest, java.util.Collection<? extends AccumulatedType> setOfValues, AccumulatedType additionalValue) Given an accumulator for setOfValues, computes an accumulator for setOfValues union {additionalValue}.
AccumulatedType	restoreAccumulatedValue(org.cryptimeleon.math.serialization.Representation repr) Restores an accumulated value of type AccumulatorType from its representation.
AccumulatorDigest	restoreDigest(org.cryptimeleon.math.serialization.Representation repr) Restores an AccumulatorDigest from its representation.
default java.lang.Object	restoreFromRepresentation(java.lang.reflect.Type type, org.cryptimeleon.math.serialization.Representation repr)
AccumulatorWitness	restoreWitness(org.cryptimeleon.math.serialization.Representation repr) Restores an AccumulatorWitness from its representation.
default AccumulatorWitness	updateWitness(AccumulatorDigest oldDigest, AccumulatorDigest newDigest, java.util.Collection<? extends AccumulatedType> oldAccumulatedSet, java.util.Collection<? extends AccumulatedType> newAccumulatedSet, AccumulatedType valueToComputeWitnessFor, AccumulatorWitness oldWitnessToBeUpdated) Updates a set membership witness with regard to accumulator changes.
boolean	verify(AccumulatorDigest accumulatorDigest, AccumulatedType singleValue, AccumulatorWitness witnessForSingleValue) Verifies that the given singleValue is indeed part of the accumulated set.

Methods inherited from interface org.cryptimeleon.math.serialization.Representable

getRepresentation

Method Detail

createDigest

AccumulatorDigest createDigest(java.util.Collection<? extends AccumulatedType> setOfValues)

Creates the accumulator for the given set of values (essentially a collision-resistant hash of setOfValues).

createWitness

AccumulatorWitness createWitness(AccumulatorDigest digest,
                                 java.util.Collection<? extends AccumulatedType> setOfAccumulatedValues,
                                 AccumulatedType valueToComputeWitnessFor)

Creates a short witness that can be used to verify set membership in an accumulator.

Parameters:

setOfAccumulatedValues - the set of values accumulated (including valueToComputeWitnessFor)

valueToComputeWitnessFor - the one value you want to prove is in there

Returns:

a short witness to be used in verify(AccumulatorDigest, Representable, AccumulatorWitness)

verify

boolean verify(AccumulatorDigest accumulatorDigest,
               AccumulatedType singleValue,
               AccumulatorWitness witnessForSingleValue)

Verifies that the given singleValue is indeed part of the accumulated set.

insert

default AccumulatorDigest insert(AccumulatorDigest digest,
                                 java.util.Collection<? extends AccumulatedType> setOfValues,
                                 AccumulatedType additionalValue)

Given an accumulator for setOfValues, computes an accumulator for setOfValues union {additionalValue}.

delete

default AccumulatorDigest delete(AccumulatorDigest digest,
                                 java.util.Collection<? extends AccumulatedType> setOfValues,
                                 AccumulatedType valueToDelete)

Given an accumulator for setOfValues, computes an accumulator for setOfValues \ {additionalValue}.

updateWitness

default AccumulatorWitness updateWitness(AccumulatorDigest oldDigest,
                                         AccumulatorDigest newDigest,
                                         java.util.Collection<? extends AccumulatedType> oldAccumulatedSet,
                                         java.util.Collection<? extends AccumulatedType> newAccumulatedSet,
                                         AccumulatedType valueToComputeWitnessFor,
                                         AccumulatorWitness oldWitnessToBeUpdated)

Updates a set membership witness with regard to accumulator changes. Equivalent to recomputing a witness using createWitness(AccumulatorDigest, Collection, Representable), but this method may be more efficient.

Parameters:

oldDigest - the "old" digest

newDigest - the "new" digest

oldAccumulatedSet - the set accumulated in oldDigest

newAccumulatedSet - the set accumulated in newDigest

valueToComputeWitnessFor - the value (present in oldDigest and in newDigest) for which a witness shall be computed

oldWitnessToBeUpdated - a witness for valueToComputeWitnessFor being part of oldDigest

Returns:

a witness for valueToComputeWitnessFor being part of newDigest (same as createWitness(newAccumulatedSet, valueToComputeWitnessFor))

getMaxNumAccumulatedValues

java.lang.Integer getMaxNumAccumulatedValues()

Returns maximum number of AccumulatedTypes that can be simultaneously accumulated in the Accumulator or null if unbounded.

restoreWitness

AccumulatorWitness restoreWitness(org.cryptimeleon.math.serialization.Representation repr)

Restores an AccumulatorWitness from its representation.

restoreDigest

AccumulatorDigest restoreDigest(org.cryptimeleon.math.serialization.Representation repr)

Restores an AccumulatorDigest from its representation.

restoreAccumulatedValue

AccumulatedType restoreAccumulatedValue(org.cryptimeleon.math.serialization.Representation repr)

Restores an accumulated value of type AccumulatorType from its representation.

restoreFromRepresentation

default java.lang.Object restoreFromRepresentation(java.lang.reflect.Type type,
                                                   org.cryptimeleon.math.serialization.Representation repr)
                                            throws java.lang.IllegalArgumentException

Specified by:

restoreFromRepresentation in interface org.cryptimeleon.math.serialization.annotations.RepresentationRestorer

Throws:

java.lang.IllegalArgumentException