ECPoint (Bouncy Castle Library 1.73 API Specification)

java.lang.Object
- org.bouncycastle.math.ec.ECPoint

Direct Known Subclasses:

ECPoint.AbstractF2m, ECPoint.AbstractFp
```
public abstract class ECPoint
extends java.lang.Object
```
base class for points on elliptic curves.

Nested Class Summary

Nested Classes
Modifier and Type	Class and Description
`static class`	`ECPoint.AbstractF2m`
`static class`	`ECPoint.AbstractFp`
`static class`	`ECPoint.F2m` Elliptic curve points over F2m
`static class`	`ECPoint.Fp` Elliptic curve points over Fp

Field Summary

Fields
Modifier and Type	Field and Description
`protected ECCurve`	`curve`
`protected static ECFieldElement[]`	`EMPTY_ZS`
`protected java.util.Hashtable`	`preCompTable`
`protected ECFieldElement`	`x`
`protected ECFieldElement`	`y`
`protected ECFieldElement[]`	`zs`

Constructor Summary

Constructors
Modifier	Constructor and Description
`protected`	`ECPoint(ECCurve curve, ECFieldElement x, ECFieldElement y)`
`protected`	`ECPoint(ECCurve curve, ECFieldElement x, ECFieldElement y, ECFieldElement[] zs)`

Method Summary

All Methods Static Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method and Description
`abstract ECPoint`	`add(ECPoint b)`
`protected void`	`checkNormalized()`
`protected ECPoint`	`createScaledPoint(ECFieldElement sx, ECFieldElement sy)`
`protected abstract ECPoint`	`detach()`
`boolean`	`equals(ECPoint other)`
`boolean`	`equals(java.lang.Object other)`
`ECFieldElement`	`getAffineXCoord()` Returns the affine x-coordinate after checking that this point is normalized.
`ECFieldElement`	`getAffineYCoord()` Returns the affine y-coordinate after checking that this point is normalized
`protected abstract boolean`	`getCompressionYTilde()`
`ECCurve`	`getCurve()`
`protected int`	`getCurveCoordinateSystem()`
`ECPoint`	`getDetachedPoint()`
`byte[]`	`getEncoded(boolean compressed)` Get an encoding of the point value, optionally in compressed format.
`protected static ECFieldElement[]`	`getInitialZCoords(ECCurve curve)`
`ECFieldElement`	`getRawXCoord()`
`ECFieldElement`	`getRawYCoord()`
`protected ECFieldElement[]`	`getRawZCoords()`
`ECFieldElement`	`getXCoord()` Returns the x-coordinate.
`ECFieldElement`	`getYCoord()` Returns the y-coordinate.
`ECFieldElement`	`getZCoord(int index)`
`ECFieldElement[]`	`getZCoords()`
`int`	`hashCode()`
`boolean`	`isInfinity()`
`boolean`	`isNormalized()`
`boolean`	`isValid()`
`ECPoint`	`multiply(java.math.BigInteger k)` Multiplies this `ECPoint` by the given number.
`abstract ECPoint`	`negate()`
`ECPoint`	`normalize()` Normalization ensures that any projective coordinate is 1, and therefore that the x, y coordinates reflect those of the equivalent point in an affine coordinate system.
`protected abstract boolean`	`satisfiesCurveEquation()`
`protected boolean`	`satisfiesOrder()`
`ECPoint`	`scaleX(ECFieldElement scale)`
`ECPoint`	`scaleXNegateY(ECFieldElement scale)`
`ECPoint`	`scaleY(ECFieldElement scale)`
`ECPoint`	`scaleYNegateX(ECFieldElement scale)`
`abstract ECPoint`	`subtract(ECPoint b)`
`ECPoint`	`threeTimes()`
`ECPoint`	`timesPow2(int e)`
`java.lang.String`	`toString()`
`abstract ECPoint`	`twice()`
`ECPoint`	`twicePlus(ECPoint b)`

Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

EMPTY_ZS

protected static final ECFieldElement[] EMPTY_ZS

curve
```
protected ECCurve curve
```

x
```
protected ECFieldElement x
```

y
```
protected ECFieldElement y
```

zs
```
protected ECFieldElement[] zs
```

preCompTable

protected java.util.Hashtable preCompTable

Constructor Detail

ECPoint

protected ECPoint(ECCurve curve,
                  ECFieldElement x,
                  ECFieldElement y)

ECPoint

protected ECPoint(ECCurve curve,
                  ECFieldElement x,
                  ECFieldElement y,
                  ECFieldElement[] zs)

Method Detail
- getInitialZCoords
```
protected static ECFieldElement[] getInitialZCoords(ECCurve curve)
```
- satisfiesCurveEquation
```
protected abstract boolean satisfiesCurveEquation()
```
- satisfiesOrder
```
protected boolean satisfiesOrder()
```
- getDetachedPoint
```
public final ECPoint getDetachedPoint()
```
- getCurve
```
public ECCurve getCurve()
```
- detach
```
protected abstract ECPoint detach()
```
- getCurveCoordinateSystem
```
protected int getCurveCoordinateSystem()
```
- getAffineXCoord
```
public ECFieldElement getAffineXCoord()
```
  Returns the affine x-coordinate after checking that this point is normalized.
  
  Returns:
  
  The affine x-coordinate of this point
  
  Throws:
  
  java.lang.IllegalStateException - if the point is not normalized
- getAffineYCoord
```
public ECFieldElement getAffineYCoord()
```
  Returns the affine y-coordinate after checking that this point is normalized
  
  Returns:
  
  The affine y-coordinate of this point
  
  Throws:
  
  java.lang.IllegalStateException - if the point is not normalized
- getXCoord
```
public ECFieldElement getXCoord()
```
  Returns the x-coordinate. Caution: depending on the curve's coordinate system, this may not be the same value as in an affine coordinate system; use normalize() to get a point where the coordinates have their affine values, or use getAffineXCoord() if you expect the point to already have been normalized.
  
  Returns:
  
  the x-coordinate of this point
- getYCoord
```
public ECFieldElement getYCoord()
```
  Returns the y-coordinate. Caution: depending on the curve's coordinate system, this may not be the same value as in an affine coordinate system; use normalize() to get a point where the coordinates have their affine values, or use getAffineYCoord() if you expect the point to already have been normalized.
  
  Returns:
  
  the y-coordinate of this point
- getZCoord
```
public ECFieldElement getZCoord(int index)
```
- getZCoords
```
public ECFieldElement[] getZCoords()
```
- getRawXCoord
```
public final ECFieldElement getRawXCoord()
```
- getRawYCoord
```
public final ECFieldElement getRawYCoord()
```
- getRawZCoords
```
protected final ECFieldElement[] getRawZCoords()
```
- checkNormalized
```
protected void checkNormalized()
```
- isNormalized
```
public boolean isNormalized()
```
- normalize
```
public ECPoint normalize()
```
  Normalization ensures that any projective coordinate is 1, and therefore that the x, y coordinates reflect those of the equivalent point in an affine coordinate system.
  
  Returns:
  
  a new ECPoint instance representing the same point, but with normalized coordinates
- createScaledPoint
```
protected ECPoint createScaledPoint(ECFieldElement sx,
                                    ECFieldElement sy)
```
- isInfinity
```
public boolean isInfinity()
```
- isValid
```
public boolean isValid()
```
- scaleX
```
public ECPoint scaleX(ECFieldElement scale)
```
- scaleXNegateY
```
public ECPoint scaleXNegateY(ECFieldElement scale)
```
- scaleY
```
public ECPoint scaleY(ECFieldElement scale)
```
- scaleYNegateX
```
public ECPoint scaleYNegateX(ECFieldElement scale)
```
- equals
```
public boolean equals(ECPoint other)
```
- 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
- toString
```
public java.lang.String toString()
```
  Overrides:
  
  toString in class java.lang.Object
- getEncoded
```
public byte[] getEncoded(boolean compressed)
```
  Get an encoding of the point value, optionally in compressed format.
  
  Parameters:
  
  compressed - whether to generate a compressed point encoding.
  
  Returns:
  
  the point encoding
- getCompressionYTilde
```
protected abstract boolean getCompressionYTilde()
```
- add
```
public abstract ECPoint add(ECPoint b)
```
- negate
```
public abstract ECPoint negate()
```
- subtract
```
public abstract ECPoint subtract(ECPoint b)
```
- timesPow2
```
public ECPoint timesPow2(int e)
```
- twice
```
public abstract ECPoint twice()
```
- twicePlus
```
public ECPoint twicePlus(ECPoint b)
```
- threeTimes
```
public ECPoint threeTimes()
```
- multiply
```
public ECPoint multiply(java.math.BigInteger k)
```
  Multiplies this ECPoint by the given number.
  
  Parameters:
  
  k - The multiplicator.
  
  Returns:
  
  k * this.

Class ECPoint

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

EMPTY_ZS

curve

x

y

zs

preCompTable

Constructor Detail

ECPoint

ECPoint

Method Detail

getInitialZCoords

satisfiesCurveEquation

satisfiesOrder

getDetachedPoint

getCurve

detach

getCurveCoordinateSystem

getAffineXCoord

getAffineYCoord

getXCoord

getYCoord

getZCoord

getZCoords

getRawXCoord

getRawYCoord

getRawZCoords

checkNormalized

isNormalized

normalize

createScaledPoint

isInfinity

isValid

scaleX

scaleXNegateY

scaleY

scaleYNegateX

equals

equals

hashCode

toString

getEncoded

getCompressionYTilde

add

negate

subtract

timesPow2

twice

twicePlus

threeTimes

multiply