org.cryptimeleon.craco.protocols.arguments.sigma

Class ZnChallengeSpace

java.lang.Object

org.cryptimeleon.craco.protocols.arguments.sigma.ZnChallengeSpace

All Implemented Interfaces:

ChallengeSpace, org.cryptimeleon.math.serialization.annotations.RepresentationRestorer

public class ZnChallengeSpace
extends java.lang.Object
implements ChallengeSpace

A challenge space where elements can be interpreted as integers 0, 1, ... size()-1.

Field Summary

Fields

Modifier and Type	Field and Description
protected org.cryptimeleon.math.structures.rings.zn.Zn	zn

Constructor Summary

Constructors

Constructor and Description
ZnChallengeSpace(java.math.BigInteger size)
ZnChallengeSpace(org.cryptimeleon.math.structures.rings.zn.Zn zn)

Method Summary

Modifier and Type	Method and Description
boolean	equals(java.lang.Object o)
ZnChallenge	generateRandomChallenge()
int	hashCode()
ZnChallenge	hashIntoChallengeSpace(byte[] bytes) Hashes the given bytes into this challenge space (in a random-oracle-like manner).
ZnChallenge	mapIntoChallengeSpace(byte[] bytes) Creates a challenge from the given byte[].
ZnChallenge	restoreChallenge(org.cryptimeleon.math.serialization.Representation repr) Restores a given challenge from representation.
java.math.BigInteger	size() Returns the size of the challenge space.
Challenge	subtract(Challenge challengeToSplit, Challenge share1) Returns the unique challenge share2 such that subtract(challengeToSplit, share2).equals(share1).

Methods inherited from class java.lang.Object

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

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

restoreFromRepresentation

Field Detail

zn

protected org.cryptimeleon.math.structures.rings.zn.Zn zn

Constructor Detail

ZnChallengeSpace

public ZnChallengeSpace(org.cryptimeleon.math.structures.rings.zn.Zn zn)

ZnChallengeSpace

public ZnChallengeSpace(java.math.BigInteger size)

Method Detail

generateRandomChallenge

public ZnChallenge generateRandomChallenge()

Specified by:

generateRandomChallenge in interface ChallengeSpace

size

public java.math.BigInteger size()
                          throws java.lang.UnsupportedOperationException

Description copied from interface: ChallengeSpace

Returns the size of the challenge space. null for infinite size, throws UnsupportedOperationException if unknown.

Specified by:

size in interface ChallengeSpace

Throws:

java.lang.UnsupportedOperationException

restoreChallenge

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

Description copied from interface: ChallengeSpace

Restores a given challenge from representation.

Specified by:

restoreChallenge in interface ChallengeSpace

mapIntoChallengeSpace

public ZnChallenge mapIntoChallengeSpace(byte[] bytes)

Description copied from interface: ChallengeSpace

Creates a challenge from the given byte[].

Given two random byte[] of the same (arbitrary) length, it should be unlikely that their challenge collides.

Specified by:

mapIntoChallengeSpace in interface ChallengeSpace

hashIntoChallengeSpace

public ZnChallenge hashIntoChallengeSpace(byte[] bytes)

Description copied from interface: ChallengeSpace

Hashes the given bytes into this challenge space (in a random-oracle-like manner). If two challenge spaces are equal, then the behavior of this method is consistent.

Specified by:

hashIntoChallengeSpace in interface ChallengeSpace

subtract

public Challenge subtract(Challenge challengeToSplit,
                          Challenge share1)
                   throws java.lang.UnsupportedOperationException

Description copied from interface: ChallengeSpace

Returns the unique challenge share2 such that subtract(challengeToSplit, share2).equals(share1). This is akin to secret sharing. For all challengeToSplit, subtract(challengeToSplit, generateRandomChallenge()) shall be distributed like generateRandomChallenge().

Specified by:

subtract in interface ChallengeSpace

Throws:

java.lang.UnsupportedOperationException - if this challenge space does not support splitting challenges.

equals

public boolean equals(java.lang.Object o)

Overrides:

equals in class java.lang.Object

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object