org.cryptimeleon.math.structures.groups.counting

Class CountingBilinearGroup

java.lang.Object

org.cryptimeleon.math.structures.groups.counting.CountingBilinearGroup

All Implemented Interfaces:

Representable, StandaloneRepresentable, BilinearGroup

public class CountingBilinearGroup
extends java.lang.Object
implements BilinearGroup

A BilinearGroup implementing a fast, but insecure pairing over Zn. Allows for counting group operations and (multi-)exponentiations as well as pairings on the bilinear group level.

The counting capability is implemented by wrapping two LazyBilinearGroups which contain CountingBilinearGroupImpls themselves. All operations are executed in both groups, one counts total group operations and one counts each (multi-)exponentiation as one unit. This allows for tracking both kinds of data.

Nested Class Summary

Nested classes/interfaces inherited from interface org.cryptimeleon.math.structures.groups.elliptic.BilinearGroup

BilinearGroup.Type

Field Summary

Fields

Modifier and Type	Field and Description
protected CountingBilinearMap	bilMap The underlying bilinear map used for applying the pairing function and counting it.
protected LazyBilinearGroup	expMultiExpBilGroup The bilinear group responsible for counting (multi-)exponentiations and group operations outside of those.
protected BilinearGroup.Type	pairingType The type of pairing this bilinear group should offer.
protected java.lang.Integer	securityParameter The security level offered by this bilinear group in number of bits.
protected LazyBilinearGroup	totalBilGroup The bilinear group responsible for counting total group operations.

Constructor Summary

Constructors

Constructor and Description
CountingBilinearGroup(BilinearGroup.Type pairingType) Initializes this prime order bilinear group of 128 bit size
CountingBilinearGroup(int securityParameter, BilinearGroup.Type pairingType) Initializes this bilinear group with the given security level, pairing type and prime group order.
CountingBilinearGroup(int securityParameter, BilinearGroup.Type pairingType, int numPrimeFactors) Initializes this bilinear group with the given security level, pairing type, and group order factoring into the given number of prime factors.
CountingBilinearGroup(Representation repr)

Method Summary

Modifier and Type	Method and Description
boolean	equals(java.lang.Object other)
java.lang.String	formatCounterData() Returns a string with all count data formatted for printing.
BilinearMap	getBilinearMap() Returns the BilinearMap (contains the pairing operation) belonging to this BilinearGroup.
Group	getG1() Returns the source group G1 associated with this bilinear group.
Group	getG2() Returns the source group G2 associated with this bilinear group.
Group	getGT() Returns the target group GT associated with this bilinear group.
HashIntoGroup	getHashIntoG1() Retrieves a hash function that maps byte arrays to G1.
HashIntoGroup	getHashIntoG2() Retrieves a hash function that maps byte arrays to G2.
HashIntoGroup	getHashIntoGT() Retrieves a hash function that maps byte arrays to GT.
GroupHomomorphism	getHomomorphismG2toG1() Retrieves the homomorphism from G2 to G1 if it exists.
long	getNumPairings() Returns the number of pairings computed in this bilinear group.
BilinearGroup.Type	getPairingType()
Representation	getRepresentation() The representation of this object.
java.lang.Integer	getSecurityLevel()
int	hashCode()
protected void	init() Initializes the underlying bilinear map bilMap.
void	resetCounters() Resets all counters, including the ones in groups G1, G2, GT.
void	resetNumPairings() Resets pairing counter.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.cryptimeleon.math.structures.groups.elliptic.BilinearGroup

getHashIntoZGroupExponent, getZn, size

Field Detail

securityParameter

protected java.lang.Integer securityParameter

The security level offered by this bilinear group in number of bits.

pairingType

protected BilinearGroup.Type pairingType

The type of pairing this bilinear group should offer.

totalBilGroup

protected LazyBilinearGroup totalBilGroup

The bilinear group responsible for counting total group operations.

expMultiExpBilGroup

protected LazyBilinearGroup expMultiExpBilGroup

The bilinear group responsible for counting (multi-)exponentiations and group operations outside of those.

bilMap

protected CountingBilinearMap bilMap

The underlying bilinear map used for applying the pairing function and counting it.

Constructor Detail

CountingBilinearGroup

public CountingBilinearGroup(int securityParameter,
                             BilinearGroup.Type pairingType,
                             int numPrimeFactors)

Initializes this bilinear group with the given security level, pairing type, and group order factoring into the given number of prime factors.

Parameters:

securityParameter - the security level in number of bits

pairingType - the type of pairing that should be offered by this bilinear group

numPrimeFactors - the number of prime factors the group order should have

CountingBilinearGroup

public CountingBilinearGroup(int securityParameter,
                             BilinearGroup.Type pairingType)

Initializes this bilinear group with the given security level, pairing type and prime group order.

Parameters:

securityParameter - the security level in number of bits

pairingType - the type of pairing that should be offered by this bilinear group

CountingBilinearGroup

public CountingBilinearGroup(BilinearGroup.Type pairingType)

Initializes this prime order bilinear group of 128 bit size

Parameters:

pairingType - the type of pairing that should be offered by this bilinear group

CountingBilinearGroup

public CountingBilinearGroup(Representation repr)

Method Detail

init

protected void init()

Initializes the underlying bilinear map bilMap.

getG1

public Group getG1()

Description copied from interface: BilinearGroup

Returns the source group G1 associated with this bilinear group.

Specified by:

getG1 in interface BilinearGroup

getG2

public Group getG2()

Description copied from interface: BilinearGroup

Returns the source group G2 associated with this bilinear group.

Specified by:

getG2 in interface BilinearGroup

getGT

public Group getGT()

Description copied from interface: BilinearGroup

Returns the target group GT associated with this bilinear group.

Specified by:

getGT in interface BilinearGroup

getBilinearMap

public BilinearMap getBilinearMap()

Description copied from interface: BilinearGroup

Returns the BilinearMap (contains the pairing operation) belonging to this BilinearGroup.

Specified by:

getBilinearMap in interface BilinearGroup

getHomomorphismG2toG1

public GroupHomomorphism getHomomorphismG2toG1()
                                        throws java.lang.UnsupportedOperationException

Description copied from interface: BilinearGroup

Retrieves the homomorphism from G2 to G1 if it exists.

Specified by:

getHomomorphismG2toG1 in interface BilinearGroup

Throws:

java.lang.UnsupportedOperationException - if no such homomorphism exists or the bilinear group is not configured to support such functionality

getHashIntoG1

public HashIntoGroup getHashIntoG1()
                            throws java.lang.UnsupportedOperationException

Description copied from interface: BilinearGroup

Retrieves a hash function that maps byte arrays to G1.

Specified by:

getHashIntoG1 in interface BilinearGroup

Throws:

java.lang.UnsupportedOperationException - if no such hash function exists or the bilinear group is not configured to support such functionality

getHashIntoG2

public HashIntoGroup getHashIntoG2()
                            throws java.lang.UnsupportedOperationException

Description copied from interface: BilinearGroup

Retrieves a hash function that maps byte arrays to G2.

Specified by:

getHashIntoG2 in interface BilinearGroup

Throws:

java.lang.UnsupportedOperationException - if no such hash function exists or the bilinear group is not configured to support such functionality

getHashIntoGT

public HashIntoGroup getHashIntoGT()
                            throws java.lang.UnsupportedOperationException

Description copied from interface: BilinearGroup

Retrieves a hash function that maps byte arrays to GT.

Specified by:

getHashIntoGT in interface BilinearGroup

Throws:

java.lang.UnsupportedOperationException - if no such hash function exists or the bilinear group is not configured to support such functionality

getSecurityLevel

public java.lang.Integer getSecurityLevel()

Specified by:

getSecurityLevel in interface BilinearGroup

getPairingType

public BilinearGroup.Type getPairingType()

Specified by:

getPairingType in interface BilinearGroup

getRepresentation

public Representation getRepresentation()

Description copied from interface: Representable

The representation of this object. Used for serialization. A convenient way to implement this is using @link ReprUtil

Specified by:

getRepresentation in interface Representable

Returns:

a Representation or null if an equal object can be recreated without any information.

See Also:

Representation

equals

public boolean equals(java.lang.Object other)

Overrides:

equals in class java.lang.Object

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object

getNumPairings

public long getNumPairings()

Returns the number of pairings computed in this bilinear group.

resetNumPairings

public void resetNumPairings()

Resets pairing counter.

resetCounters

public void resetCounters()

Resets all counters, including the ones in groups G1, G2, GT.

formatCounterData

public java.lang.String formatCounterData()

Returns a string with all count data formatted for printing.