ch.epfl.dedis.lib.crypto.bn256

Class BN.G2

java.lang.Object

ch.epfl.dedis.lib.crypto.bn256.BN.G2

Enclosing class:

BN

public static class BN.G2
extends Object

A point in G2. This object is not thread-safe.

Field Summary

Fields

Modifier and Type	Field and Description
static int	ELEM_SIZE
static int	MARSHAL_SIZE

Constructor Summary

Constructors

Constructor and Description
G2() Construct a G2 point.
G2(BigInteger k) Construct a point for a scalar.
G2(BN.G2 p) Copy construct for G2.
G2(ch.epfl.dedis.lib.crypto.bn256.TwistPoint p) Construct a G2 point from an existing TwistPoint.

Method Summary

Modifier and Type	Method and Description
BN.G2	add(BN.G2 a, BN.G2 b) Perform a point addition.
boolean	isInfinity() Checks whether the point is an infinity (zero) point.
byte[]	marshal() Turns the point into its byte representation.
BN.G2	neg(BN.G2 a) Perform a point negation.
static BN.PairG2	rand(Random rnd) Generate a random pair of a point and a scalar that is used to create the point.
BN.G2	scalarBaseMul(BigInteger k) Perform a scalar multiplication with the generator point.
BN.G2	scalarMul(BN.G2 a, BigInteger k) Perform a scalar multiplication.
BN.G2	setInfinity() Set the point to the infinity (zero) point.
String	toString()
BN.G2	unmarshal(byte[] m) Turns the byte representation to the point.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

ELEM_SIZE

public static final int ELEM_SIZE

See Also:

Constant Field Values

MARSHAL_SIZE

public static final int MARSHAL_SIZE

See Also:

Constant Field Values

Constructor Detail

G2

public G2()

Construct a G2 point. We make no guarantee on its value, please set it later.

G2

public G2(ch.epfl.dedis.lib.crypto.bn256.TwistPoint p)

Construct a G2 point from an existing TwistPoint.

Parameters:

p - is the twist point.

G2

public G2(BN.G2 p)

Copy construct for G2.

Parameters:

p - is G2 point to be copied.

G2

public G2(BigInteger k)

Construct a point for a scalar.

Parameters:

k - is the scalar that is multiplied to the generator point to create the object.

Method Detail

rand

public static BN.PairG2 rand(Random rnd)

Generate a random pair of a point and a scalar that is used to create the point.

Parameters:

rnd - is the random source.

Returns:

a pair of a point and a scalar.

toString

public String toString()

Overrides:

toString in class Object

scalarBaseMul

public BN.G2 scalarBaseMul(BigInteger k)

Perform a scalar multiplication with the generator point.

Parameters:

k - is the scalar.

Returns:

the result which is also this object.

scalarMul

public BN.G2 scalarMul(BN.G2 a,
                       BigInteger k)

Perform a scalar multiplication.

Parameters:

a - is the point.

k - is the scalar.

Returns:

the result which is also this object.

add

public BN.G2 add(BN.G2 a,
                 BN.G2 b)

Perform a point addition.

Parameters:

a - is a point.

b - is a point.

Returns:

the resulting point which is also this object.

neg

public BN.G2 neg(BN.G2 a)

Perform a point negation.

Parameters:

a - is the point to negate.

Returns:

the resulting point which is also this object.

setInfinity

public BN.G2 setInfinity()

Set the point to the infinity (zero) point.

isInfinity

public boolean isInfinity()

Checks whether the point is an infinity (zero) point.

Returns:

true if the point is at infinity.

marshal

public byte[] marshal()

Turns the point into its byte representation.

Returns:

the marshalled bytes.

unmarshal

public BN.G2 unmarshal(byte[] m)

Turns the byte representation to the point.

Parameters:

m - the input bytes.

Returns:

an unmarshalled point when successful, otherwise null.