org.cryptimeleon.craco.commitment

Interface CommitmentScheme

All Superinterfaces:

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

All Known Implementing Classes:

HashThenCommitCommitmentScheme, PedersenCommitmentScheme, TCAKOT15CommitmentScheme, TCGAKOT15CommitmentScheme

public interface CommitmentScheme
extends org.cryptimeleon.math.serialization.StandaloneRepresentable, org.cryptimeleon.math.serialization.annotations.RepresentationRestorer

Interface used to implement commitment schemes.

Method Summary

Modifier and Type	Method and Description
CommitmentPair	commit(PlainText plainText) Creates a commitment to the given PlainText.
int	getMaxNumberOfBytesForMapToPlaintext() Returns the maximal number of bytes that can be mapped injectively to a PlainText by mapToPlaintext(byte[])
PlainText	mapToPlaintext(byte[] bytes) Provides an injective mapping of the given byte[] to a PlainText usable with this scheme (which may be a MessageBlock).
Commitment	restoreCommitment(org.cryptimeleon.math.serialization.Representation repr)
default CommitmentPair	restoreCommitmentPair(org.cryptimeleon.math.serialization.Representation repr)
default java.lang.Object	restoreFromRepresentation(java.lang.reflect.Type type, org.cryptimeleon.math.serialization.Representation repr)
OpenValue	restoreOpenValue(org.cryptimeleon.math.serialization.Representation repr)
boolean	verify(Commitment commitment, OpenValue openValue, PlainText plainText) Verifies that the given announced PlainText equals the result of opening the Commitment with the OpenValue.

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

getRepresentation

Method Detail

commit

CommitmentPair commit(PlainText plainText)

Creates a commitment to the given PlainText.

Parameters:

plainText - the message to commit to

Returns:

the CommitmentPair containing the commitment and an OpenValue that can be used to reveal the committed message.

verify

boolean verify(Commitment commitment,
               OpenValue openValue,
               PlainText plainText)

Verifies that the given announced PlainText equals the result of opening the Commitment with the OpenValue.

A commitment scheme such as HashThenCommitCommitmentScheme may also hash the message before committing to it. This method can take this into account, i.e. by hashing the given announced plaintext before comparing.

Parameters:

commitment - commitment to verify

openValue - used to open the commitment and reveal the content

plainText - the hash of this will be compared with the opened commitment message

Returns:

true if verification succeeds, else false

mapToPlaintext

PlainText mapToPlaintext(byte[] bytes)

Provides an injective mapping of the given byte[] to a PlainText usable with this scheme (which may be a MessageBlock). It only guarantees injectivity for arrays of the same length. Applications that would like to use mapToPlaintext with multiple different array lengths may want to devise a padding method and then only call mapToPlaintext with byte arrays of the same (padded) length.

Parameters:

bytes - byte[] to map to a PlainText that can be committed to using this commitment scheme

Returns:

PlainText usable with this commitment scheme

Throws:

java.lang.IllegalArgumentException - if there is no injective PlainText element corresponding to the given bytes, for example if the byte array is too long

getMaxNumberOfBytesForMapToPlaintext

int getMaxNumberOfBytesForMapToPlaintext()

Returns the maximal number of bytes that can be mapped injectively to a PlainText by mapToPlaintext(byte[])

As described in mapToPlaintext(byte[]) there might be no injective PlainText for some byte arrays, e.g. if the byte array is too long. Therefore, this method provides the maximal number of bytes that can be mapped injectively to a PlainText.

Returns:

maximal number of bytes that can be given to mapToPlaintext(byte[]).

restoreCommitmentPair

default CommitmentPair restoreCommitmentPair(org.cryptimeleon.math.serialization.Representation repr)

restoreCommitment

Commitment restoreCommitment(org.cryptimeleon.math.serialization.Representation repr)

restoreOpenValue

OpenValue restoreOpenValue(org.cryptimeleon.math.serialization.Representation repr)

restoreFromRepresentation

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

Specified by:

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