it.unisa.dia.gas.jpbc

Interface Pairing

public interface Pairing

This interface gives access to the pairing functions. Pairings involve three groups of prime order r called G1, G2, and GT. The pairing is a bilinear map that takes two elements as input, one from G1 and one from G2, and outputs an element of GT. Sometimes G1 and G2 are the same group (i.e. the pairing is symmetric) so their elements can be mixed freely. In this case the #isSymmetric() function returns true.

Since:

1.0.0

Author:

Angelo De Caro (jpbclib@gmail.com)

See Also:

Element, Field, PairingPreProcessing

Method Summary

Methods

Modifier and Type	Method and Description
int	getDegree() Returns the degree of the pairing.
Field	getFieldAt(int index) Returns the field at level index.
int	getFieldIndex(Field field) Returns the index of the field if it belongs to this pairing, otherwise it returns -1.
Field	getG1() Return the G1 group.
Field	getG2() Return the G2 group.
Field	getGT() Return the GT group which is the group of rth roots of unity.
PairingPreProcessing	getPairingPreProcessingFromBytes(byte[] source) Reads a PairingPreProcessing from the buffer source.
PairingPreProcessing	getPairingPreProcessingFromBytes(byte[] source, int offset) Reads a PairingPreProcessing from the buffer source starting from offset.
PairingPreProcessing	getPairingPreProcessingFromElement(Element in1) Get ready to perform a pairing whose first input is in1, returns the results of time-saving pre-computation.
int	getPairingPreProcessingLengthInBytes() Returns the length in bytes needed to represent a PairingPreProcessing structure.
Field	getZr() Return the Zr group.
boolean	isProductPairingSupported() Returns true if optimized product of pairing is supported, false otherwise.
boolean	isSymmetric() Returns true if this pairing is symmetric, false otherwise.
Element	pairing(Element[] in1, Element[] in2) Computes the product of pairings, that is 'e'('in1'[0], 'in2'[0]) ...
Element	pairing(Element in1, Element in2) Applies the bilinear map.

Method Detail

isSymmetric

boolean isSymmetric()

Returns true if this pairing is symmetric, false otherwise.

Returns:

true if this pairing is symmetric, false otherwise.

Since:

1.0.0

getDegree

int getDegree()

Returns the degree of the pairing. For bilinear maps, this value is 2. For multilinear maps, this value represents the degree of linearity supported.

Returns:

the degree of the pairing.

Since:

2.0.0

getG1

Field getG1()

Return the G1 group.

Returns:

the G1 group.

Since:

1.0.0

getG2

Field getG2()

Return the G2 group.

Returns:

the G2 group.

Since:

1.0.0

getGT

Field getGT()

Return the GT group which is the group of rth roots of unity.

Returns:

the GT group.

Since:

1.0.0

getZr

Field getZr()

Return the Zr group.

Returns:

the Zr group.

Since:

1.0.0

getFieldAt

Field getFieldAt(int index)

Returns the field at level index. For bilinear maps, Zr has index 0, G1 has index 1, G2 has index 2 and GT has index 3.

Returns:

Returns the field at level index

Since:

2.0.0

getFieldIndex

int getFieldIndex(Field field)

Returns the index of the field if it belongs to this pairing, otherwise it returns -1.

Parameters:

field - the field whose index has to be determine.

Returns:

the index of the field if it belongs to this pairing, otherwise it returns Unknown.

Since:

2.0.0

See Also:

getFieldAt(int)

pairing

Element pairing(Element in1,
              Element in2)

Applies the bilinear map. It returns e(in1, in2). g1 must be in the group G1, g2 must be in the group G2.

Parameters:

in1 - an element from G1.

in2 - an element from G2.

Returns:

an element from GT whose value is assigned by this map applied to in1 and in2.

Since:

1.0.0

isProductPairingSupported

boolean isProductPairingSupported()

Returns true if optimized product of pairing is supported, false otherwise. If optimized product of pairing is supported then invoking the #pairing(Element[], Element[]) method should guarantee better performance.

Returns:

true if optimized product of pairing is supported, false otherwise.

Since:

2.0.0

See Also:

pairing(Element[], Element[])

pairing

Element pairing(Element[] in1,
              Element[] in2)

Computes the product of pairings, that is 'e'('in1'[0], 'in2'[0]) ... 'e'('in1'[n-1], 'in2'[n-1]).

Parameters:

in1 - must have at least 'n' elements belonging to the groups G1

in2 - must have at least 'n' elements belonging to the groups G2

Returns:

the product of pairings, that is 'e'('in1'[0], 'in2'[0]) ... 'e'('in1'[n-1], 'in2'[n-1]).

Since:

1.1.0

getPairingPreProcessingLengthInBytes

int getPairingPreProcessingLengthInBytes()

Returns the length in bytes needed to represent a PairingPreProcessing structure.

Returns:

the length in bytes needed to represent a PairingPreProcessing structure.

Since:

1.2.0

See Also:

getPairingPreProcessingFromBytes(byte[]), getPairingPreProcessingFromElement(Element), PairingPreProcessing

getPairingPreProcessingFromElement

PairingPreProcessing getPairingPreProcessingFromElement(Element in1)

Get ready to perform a pairing whose first input is in1, returns the results of time-saving pre-computation.

Parameters:

in1 - the first input of a pairing execution, used to pre-compute the pairing.

Returns:

the results of time-saving pre-computation.

Since:

1.0.0

getPairingPreProcessingFromBytes

PairingPreProcessing getPairingPreProcessingFromBytes(byte[] source)

Reads a PairingPreProcessing from the buffer source.

Parameters:

source - the source of bytes.

Returns:

the PairingPreProcessing instance.

Since:

1.2.0

getPairingPreProcessingFromBytes

PairingPreProcessing getPairingPreProcessingFromBytes(byte[] source,
                                                    int offset)

Reads a PairingPreProcessing from the buffer source starting from offset.

Parameters:

source - the source of bytes.

offset - the starting offset.

Returns:

the PairingPreProcessing instance.

Since:

1.2.0