org.cryptimeleon.math.structures.groups.counting

Class CountingBilinearMap

java.lang.Object

org.cryptimeleon.math.structures.groups.counting.CountingBilinearMap

All Implemented Interfaces:

java.util.function.BiFunction<GroupElement,GroupElement,GroupElement>, BilinearMap

public class CountingBilinearMap
extends java.lang.Object
implements BilinearMap

A BilinearMap 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 bilinear map works by mapping (Zn,+) x (Zn,+) to (Zn,+) via (a,b) -> a*b (multiplication in Zn). It is insecure since DLOG is trivial in Zn.

The counting capability is implemented by wrapping two LazyBilinearMaps 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.

See Also:

CountingBilinearGroup

Constructor Summary

Constructors

Constructor and Description
CountingBilinearMap(LazyBilinearMap totalBilMap, LazyBilinearMap expMultiExpBilMap)
CountingBilinearMap(Representation repr)

Method Summary

Modifier and Type	Method and Description
GroupElement	apply(GroupElement g1, GroupElement g2) Corresponds to this.apply(g1, g2, 1).
GroupElement	apply(GroupElement g1, GroupElement g2, java.math.BigInteger exponent) Computes \(e(g1,g2)^\text{exponent}\).
boolean	equals(java.lang.Object other)
java.lang.String	formatCounterData()
Group	getG1() Returns the source group G1 associated with this bilinear map.
Group	getG2() Returns the source group G2 associated with this bilinear map.
Group	getGT() Returns the target group GT associated with this bilinear map.
long	getNumPairings() Retrieves number of pairings computed in this bilinear group.
int	hashCode()
boolean	isSymmetric() Returns true if e(g,h).equals(e(h,g)) for all g, h.
void	resetNumPairings() Resets pairing counter.
java.lang.String	toString()

Methods inherited from class java.lang.Object

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

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

apply, apply, applyExpr, applyExpr, applyExpr, applyExpr, innerProduct

Methods inherited from interface java.util.function.BiFunction

andThen

Constructor Detail

CountingBilinearMap

public CountingBilinearMap(LazyBilinearMap totalBilMap,
                           LazyBilinearMap expMultiExpBilMap)

CountingBilinearMap

public CountingBilinearMap(Representation repr)

Method Detail

getG1

public Group getG1()

Description copied from interface: BilinearMap

Returns the source group G1 associated with this bilinear map.

Specified by:

getG1 in interface BilinearMap

getG2

public Group getG2()

Description copied from interface: BilinearMap

Returns the source group G2 associated with this bilinear map.

Specified by:

getG2 in interface BilinearMap

getGT

public Group getGT()

Description copied from interface: BilinearMap

Returns the target group GT associated with this bilinear map.

Specified by:

getGT in interface BilinearMap

apply

public GroupElement apply(GroupElement g1,
                          GroupElement g2,
                          java.math.BigInteger exponent)

Description copied from interface: BilinearMap

Computes \(e(g1,g2)^\text{exponent}\).

Depending on the bilinear map and the involved groups, this may be more efficiently implemented than computing it directly via apply(g1,g2).pow(exponent). For example, implementations should do exponentiation in the group with the cheapest group operation.

Specified by:

apply in interface BilinearMap

Parameters:

g1 - left hand side argument for the pairing function

g2 - right hand side argument for the pairing function

exponent - the exponent to apply to the result of the pairing

apply

public GroupElement apply(GroupElement g1,
                          GroupElement g2)

Description copied from interface: BilinearMap

Corresponds to this.apply(g1, g2, 1).

Specified by:

apply in interface java.util.function.BiFunction<GroupElement,GroupElement,GroupElement>

Specified by:

apply in interface BilinearMap

Parameters:

g1 - left hand side argument for the pairing function

g2 - right hand side argument for the pairing function

isSymmetric

public boolean isSymmetric()

Description copied from interface: BilinearMap

Returns true if e(g,h).equals(e(h,g)) for all g, h.

Specified by:

isSymmetric in interface BilinearMap

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()

Retrieves number of pairings computed in this bilinear group.

resetNumPairings

public void resetNumPairings()

Resets pairing counter.

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

formatCounterData

public java.lang.String formatCounterData()