- java.lang.Object
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- java.security.spec.EllipticCurve
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public class EllipticCurve extends Object
This immutable class holds the necessary values needed to represent an elliptic curve.- Since:
- 1.5
- See Also:
ECField,ECFieldFp,ECFieldF2m
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Constructor Summary
Constructors Constructor Description EllipticCurve(ECField field, BigInteger a, BigInteger b)Creates an elliptic curve with the specified elliptic fieldfieldand the coefficientsaandb.EllipticCurve(ECField field, BigInteger a, BigInteger b, byte[] seed)Creates an elliptic curve with the specified elliptic fieldfield, the coefficientsaandb, and theseedused for curve generation.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description booleanequals(Object obj)Compares this elliptic curve for equality with the specified object.BigIntegergetA()Returns the first coefficientaof the elliptic curve.BigIntegergetB()Returns the second coefficientbof the elliptic curve.ECFieldgetField()Returns the finite fieldfieldthat this elliptic curve is over.byte[]getSeed()Returns the seeding bytesseedused during curve generation.inthashCode()Returns a hash code value for this elliptic curve.
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Constructor Detail
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EllipticCurve
public EllipticCurve(ECField field, BigInteger a, BigInteger b)
Creates an elliptic curve with the specified elliptic fieldfieldand the coefficientsaandb.- Parameters:
field- the finite field that this elliptic curve is over.a- the first coefficient of this elliptic curve.b- the second coefficient of this elliptic curve.- Throws:
NullPointerException- iffield,a, orbis null.IllegalArgumentException- ifaorbis not null and not infield.
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EllipticCurve
public EllipticCurve(ECField field, BigInteger a, BigInteger b, byte[] seed)
Creates an elliptic curve with the specified elliptic fieldfield, the coefficientsaandb, and theseedused for curve generation.- Parameters:
field- the finite field that this elliptic curve is over.a- the first coefficient of this elliptic curve.b- the second coefficient of this elliptic curve.seed- the bytes used during curve generation for later validation. Contents of this array are copied to protect against subsequent modification.- Throws:
NullPointerException- iffield,a, orbis null.IllegalArgumentException- ifaorbis not null and not infield.
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Method Detail
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getField
public ECField getField()
Returns the finite fieldfieldthat this elliptic curve is over.- Returns:
- the field
fieldthat this curve is over.
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getA
public BigInteger getA()
Returns the first coefficientaof the elliptic curve.- Returns:
- the first coefficient
a.
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getB
public BigInteger getB()
Returns the second coefficientbof the elliptic curve.- Returns:
- the second coefficient
b.
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getSeed
public byte[] getSeed()
Returns the seeding bytesseedused during curve generation. May be null if not specified.- Returns:
- the seeding bytes
seed. A new array is returned each time this method is called.
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equals
public boolean equals(Object obj)
Compares this elliptic curve for equality with the specified object.- Overrides:
equalsin classObject- Parameters:
obj- the object to be compared.- Returns:
- true if
objis an instance of EllipticCurve and the field, A, and B match, false otherwise. - See Also:
Object.hashCode(),HashMap
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hashCode
public int hashCode()
Returns a hash code value for this elliptic curve.- Overrides:
hashCodein classObject- Returns:
- a hash code value computed from the hash codes of the field, A,
and B, as follows:
(field.hashCode() << 6) + (a.hashCode() << 4) + (b.hashCode() << 2) - See Also:
Object.equals(java.lang.Object),System.identityHashCode(java.lang.Object)
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