ECCurve (core 1.58.0.0 API)

java.lang.Object
- org.spongycastle.math.ec.ECCurve

Direct Known Subclasses:

ECCurve.AbstractF2m, ECCurve.AbstractFp
```
public abstract class ECCurve
extends java.lang.Object
```
base class for an elliptic curve

Nested Class Summary

Nested Classes
Modifier and Type	Class and Description
`static class`	`ECCurve.AbstractF2m`
`static class`	`ECCurve.AbstractFp`
`class`	`ECCurve.Config`
`static class`	`ECCurve.F2m` Elliptic curves over F2m.
`static class`	`ECCurve.Fp` Elliptic curve over Fp

Field Summary

Fields
Modifier and Type	Field and Description
`protected ECFieldElement`	`a`
`protected ECFieldElement`	`b`
`protected java.math.BigInteger`	`cofactor`
`protected int`	`coord`
`static int`	`COORD_AFFINE`
`static int`	`COORD_HOMOGENEOUS`
`static int`	`COORD_JACOBIAN`
`static int`	`COORD_JACOBIAN_CHUDNOVSKY`
`static int`	`COORD_JACOBIAN_MODIFIED`
`static int`	`COORD_LAMBDA_AFFINE`
`static int`	`COORD_LAMBDA_PROJECTIVE`
`static int`	`COORD_SKEWED`
`protected ECEndomorphism`	`endomorphism`
`protected FiniteField`	`field`
`protected ECMultiplier`	`multiplier`
`protected java.math.BigInteger`	`order`

Constructor Summary

Constructors
Modifier Constructor and Description

protected ECCurve(FiniteField field)

Constructors
Modifier	Constructor and Description
`protected`	`ECCurve(FiniteField field)`

Method Summary

All Methods Static Methods Instance Methods Abstract Methods Concrete Methods Deprecated Methods
Modifier and Type	Method and Description
`protected void`	`checkPoint(ECPoint point)`
`protected void`	`checkPoints(ECPoint[] points)`
`protected void`	`checkPoints(ECPoint[] points, int off, int len)`
`protected abstract ECCurve`	`cloneCurve()`
`ECCurve.Config`	`configure()`
`protected ECMultiplier`	`createDefaultMultiplier()`
`ECPoint`	`createPoint(java.math.BigInteger x, java.math.BigInteger y)`
`ECPoint`	`createPoint(java.math.BigInteger x, java.math.BigInteger y, boolean withCompression)` Deprecated. per-point compression property will be removed, use `createPoint(BigInteger, BigInteger)` and refer `ECPoint.getEncoded(boolean)`
`protected abstract ECPoint`	`createRawPoint(ECFieldElement x, ECFieldElement y, boolean withCompression)`
`protected abstract ECPoint`	`createRawPoint(ECFieldElement x, ECFieldElement y, ECFieldElement[] zs, boolean withCompression)`
`ECPoint`	`decodePoint(byte[] encoded)` Decode a point on this curve from its ASN.1 encoding.
`protected abstract ECPoint`	`decompressPoint(int yTilde, java.math.BigInteger X1)`
`boolean`	`equals(ECCurve other)`
`boolean`	`equals(java.lang.Object obj)`
`abstract ECFieldElement`	`fromBigInteger(java.math.BigInteger x)`
`ECFieldElement`	`getA()`
`static int[]`	`getAllCoordinateSystems()`
`ECFieldElement`	`getB()`
`java.math.BigInteger`	`getCofactor()`
`int`	`getCoordinateSystem()`
`ECEndomorphism`	`getEndomorphism()`
`FiniteField`	`getField()`
`abstract int`	`getFieldSize()`
`abstract ECPoint`	`getInfinity()`
`ECMultiplier`	`getMultiplier()` Sets the default `ECMultiplier`, unless already set.
`java.math.BigInteger`	`getOrder()`
`PreCompInfo`	`getPreCompInfo(ECPoint point, java.lang.String name)`
`int`	`hashCode()`
`ECPoint`	`importPoint(ECPoint p)`
`abstract boolean`	`isValidFieldElement(java.math.BigInteger x)`
`void`	`normalizeAll(ECPoint[] points)` 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.
`void`	`normalizeAll(ECPoint[] points, int off, int len, ECFieldElement iso)` 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.
`void`	`setPreCompInfo(ECPoint point, java.lang.String name, PreCompInfo preCompInfo)` Adds `PreCompInfo` for a point on this curve, under a given name.
`boolean`	`supportsCoordinateSystem(int coord)`
`ECPoint`	`validatePoint(java.math.BigInteger x, java.math.BigInteger y)`
`ECPoint`	`validatePoint(java.math.BigInteger x, java.math.BigInteger y, boolean withCompression)` Deprecated. per-point compression property will be removed, use `validatePoint(BigInteger, BigInteger)` and refer `ECPoint.getEncoded(boolean)`

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

Field Detail

COORD_AFFINE
```
public static final int COORD_AFFINE
```
See Also:

Constant Field Values

COORD_HOMOGENEOUS
```
public static final int COORD_HOMOGENEOUS
```
See Also:

Constant Field Values

COORD_JACOBIAN
```
public static final int COORD_JACOBIAN
```
See Also:

Constant Field Values

COORD_JACOBIAN_CHUDNOVSKY
```
public static final int COORD_JACOBIAN_CHUDNOVSKY
```
See Also:

Constant Field Values

COORD_JACOBIAN_MODIFIED
```
public static final int COORD_JACOBIAN_MODIFIED
```
See Also:

Constant Field Values

COORD_LAMBDA_AFFINE
```
public static final int COORD_LAMBDA_AFFINE
```
See Also:

Constant Field Values

COORD_LAMBDA_PROJECTIVE
```
public static final int COORD_LAMBDA_PROJECTIVE
```
See Also:

Constant Field Values

COORD_SKEWED
```
public static final int COORD_SKEWED
```
See Also:

Constant Field Values

field
```
protected FiniteField field
```

a
```
protected ECFieldElement a
```

b
```
protected ECFieldElement b
```

order
```
protected java.math.BigInteger order
```

cofactor

protected java.math.BigInteger cofactor

coord
```
protected int coord
```

endomorphism
```
protected ECEndomorphism endomorphism
```

multiplier
```
protected ECMultiplier multiplier
```

Constructor Detail
- ECCurve
```
protected ECCurve(FiniteField field)
```

Method Detail

getAllCoordinateSystems

public static int[] getAllCoordinateSystems()

getFieldSize
```
public abstract int getFieldSize()
```

fromBigInteger

public abstract ECFieldElement fromBigInteger(java.math.BigInteger x)

isValidFieldElement

public abstract boolean isValidFieldElement(java.math.BigInteger x)

configure
```
public ECCurve.Config configure()
```

validatePoint

public ECPoint validatePoint(java.math.BigInteger x,
                             java.math.BigInteger y)

validatePoint

public ECPoint validatePoint(java.math.BigInteger x,
                             java.math.BigInteger y,
                             boolean withCompression)

Deprecated. per-point compression property will be removed, use validatePoint(BigInteger, BigInteger) and refer ECPoint.getEncoded(boolean)

createPoint

public ECPoint createPoint(java.math.BigInteger x,
                           java.math.BigInteger y)

createPoint

public ECPoint createPoint(java.math.BigInteger x,
                           java.math.BigInteger y,
                           boolean withCompression)

Deprecated. per-point compression property will be removed, use createPoint(BigInteger, BigInteger) and refer ECPoint.getEncoded(boolean)

cloneCurve

protected abstract ECCurve cloneCurve()

createRawPoint

protected abstract ECPoint createRawPoint(ECFieldElement x,
                                          ECFieldElement y,
                                          boolean withCompression)

createRawPoint

protected abstract ECPoint createRawPoint(ECFieldElement x,
                                          ECFieldElement y,
                                          ECFieldElement[] zs,
                                          boolean withCompression)

createDefaultMultiplier

protected ECMultiplier createDefaultMultiplier()

supportsCoordinateSystem

public boolean supportsCoordinateSystem(int coord)

getPreCompInfo

public PreCompInfo getPreCompInfo(ECPoint point,
                                  java.lang.String name)

setPreCompInfo
```
public void setPreCompInfo(ECPoint point,
                           java.lang.String name,
                           PreCompInfo preCompInfo)
```
Adds PreCompInfo for a point on this curve, under a given name. Used by ECMultipliers to save the precomputation for this ECPoint for use by subsequent multiplication.

Parameters:

point - The ECPoint to store precomputations for.

name - A String used to index precomputations of different types.

preCompInfo - The values precomputed by the ECMultiplier.

importPoint

public ECPoint importPoint(ECPoint p)

normalizeAll
```
public void normalizeAll(ECPoint[] points)
```
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. Where more than one point is to be normalized, this method will generally be more efficient than normalizing each point separately.

Parameters:

points - An array of points that will be updated in place with their normalized versions, where necessary

normalizeAll
```
public void normalizeAll(ECPoint[] points,
                         int off,
                         int len,
                         ECFieldElement iso)
```
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. Where more than one point is to be normalized, this method will generally be more efficient than normalizing each point separately. An (optional) z-scaling factor can be applied; effectively each z coordinate is scaled by this value prior to normalization (but only one actual multiplication is needed).

Parameters:

points - An array of points that will be updated in place with their normalized versions, where necessary

off - The start of the range of points to normalize

len - The length of the range of points to normalize

iso - The (optional) z-scaling factor - can be null

getInfinity
```
public abstract ECPoint getInfinity()
```

getField
```
public FiniteField getField()
```

getA
```
public ECFieldElement getA()
```

getB
```
public ECFieldElement getB()
```

getOrder

public java.math.BigInteger getOrder()

getCofactor

public java.math.BigInteger getCofactor()

getCoordinateSystem
```
public int getCoordinateSystem()
```

decompressPoint

protected abstract ECPoint decompressPoint(int yTilde,
                                           java.math.BigInteger X1)

getEndomorphism

public ECEndomorphism getEndomorphism()

getMultiplier
```
public ECMultiplier getMultiplier()
```
Sets the default ECMultiplier, unless already set.

decodePoint
```
public ECPoint decodePoint(byte[] encoded)
```
Decode a point on this curve from its ASN.1 encoding. The different encodings are taken account of, including point compression for F_p (X9.62 s 4.2.1 pg 17).

Returns:

The decoded point.

checkPoint

protected void checkPoint(ECPoint point)

checkPoints

protected void checkPoints(ECPoint[] points)

checkPoints

protected void checkPoints(ECPoint[] points,
                           int off,
                           int len)

equals
```
public boolean equals(ECCurve other)
```

equals

public boolean equals(java.lang.Object obj)

Overrides:: equals in class java.lang.Object

hashCode
```
public int hashCode()
```
Overrides:

hashCode in class java.lang.Object

Class ECCurve

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

COORD_AFFINE

COORD_HOMOGENEOUS

COORD_JACOBIAN

COORD_JACOBIAN_CHUDNOVSKY

COORD_JACOBIAN_MODIFIED

COORD_LAMBDA_AFFINE

COORD_LAMBDA_PROJECTIVE

COORD_SKEWED

field

a

b

order

cofactor

coord

endomorphism

multiplier

Constructor Detail

ECCurve

Method Detail

getAllCoordinateSystems

getFieldSize

fromBigInteger

isValidFieldElement

configure

validatePoint

validatePoint

createPoint

createPoint

cloneCurve

createRawPoint

createRawPoint

createDefaultMultiplier

supportsCoordinateSystem

getPreCompInfo

setPreCompInfo

importPoint

normalizeAll

normalizeAll

getInfinity

getField

getA

getB

getOrder

getCofactor

getCoordinateSystem

decompressPoint

getEndomorphism

getMultiplier

decodePoint

checkPoint

checkPoints

checkPoints

equals

equals

hashCode