# EllipticCurve Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels) # EllipticCurve ``` open class EllipticCurve ``` |---|----------------------------------------------------------------------------------------------------------------------| | [kotlin.Any](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-any/index.html) || | ↳ | [java.security.spec.EllipticCurve](https://developer.android.com/reference/kotlin/java/security/spec/EllipticCurve#) | This immutable class holds the necessary values needed to represent an elliptic curve. ## Summary | Public constructors || |-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|---| | [EllipticCurve](https://developer.android.com/reference/kotlin/java/security/spec/EllipticCurve#EllipticCurve(java.security.spec.ECField,%20java.math.BigInteger,%20java.math.BigInteger))`(`field:` `[ECField](https://developer.android.com/reference/kotlin/java/security/spec/ECField)!`, `a:` `[BigInteger](https://developer.android.com/reference/kotlin/java/math/BigInteger.html#)!`, `b:` `[BigInteger](https://developer.android.com/reference/kotlin/java/math/BigInteger.html#)!`)` Creates an elliptic curve with the specified elliptic field`field`and the coefficients`a`and`b`. | | [EllipticCurve](https://developer.android.com/reference/kotlin/java/security/spec/EllipticCurve#EllipticCurve(java.security.spec.ECField,%20java.math.BigInteger,%20java.math.BigInteger,%20kotlin.ByteArray))`(`field:` `[ECField](https://developer.android.com/reference/kotlin/java/security/spec/ECField)!`, `a:` `[BigInteger](https://developer.android.com/reference/kotlin/java/math/BigInteger.html#)!`, `b:` `[BigInteger](https://developer.android.com/reference/kotlin/java/math/BigInteger.html#)!`, `seed:` `[ByteArray](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-byte-array/index.html)!`)` Creates an elliptic curve with the specified elliptic field`field`, the coefficients`a`and`b`, and the`seed`used for curve generation. | | Public methods || |----------------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | open[Boolean](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-boolean/index.html) | [equals](https://developer.android.com/reference/kotlin/java/security/spec/EllipticCurve#equals(kotlin.Any))`(`other:` `[Any](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-any/index.html)?`)` Compares this elliptic curve for equality with the specified object. | | open[BigInteger](https://developer.android.com/reference/kotlin/java/math/BigInteger.html#)! | [getA](https://developer.android.com/reference/kotlin/java/security/spec/EllipticCurve#getA())`()` Returns the first coefficient`a`of the elliptic curve. | | open[BigInteger](https://developer.android.com/reference/kotlin/java/math/BigInteger.html#)! | [getB](https://developer.android.com/reference/kotlin/java/security/spec/EllipticCurve#getB())`()` Returns the second coefficient`b`of the elliptic curve. | | open[ECField](https://developer.android.com/reference/kotlin/java/security/spec/ECField)! | [getField](https://developer.android.com/reference/kotlin/java/security/spec/EllipticCurve#getField())`()` Returns the finite field`field`that this elliptic curve is over. | | open[ByteArray](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-byte-array/index.html)! | [getSeed](https://developer.android.com/reference/kotlin/java/security/spec/EllipticCurve#getSeed())`()` Returns the seeding bytes`seed`used during curve generation. | | open[Int](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-int/index.html) | [hashCode](https://developer.android.com/reference/kotlin/java/security/spec/EllipticCurve#hashCode())`()` Returns a hash code value for this elliptic curve. | ## Public constructors ### EllipticCurve Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels) ``` EllipticCurve(     field: ECField!,     a: BigInteger!,     b: BigInteger!) ``` Creates an elliptic curve with the specified elliptic field`field`and the coefficients`a`and`b`. | Parameters || |---------|------------------------------------------------------------------------------------------------------------------------------------------| | `field` | [ECField](https://developer.android.com/reference/kotlin/java/security/spec/ECField)!:the finite field that this elliptic curve is over. | | `a` | [BigInteger](https://developer.android.com/reference/kotlin/java/math/BigInteger.html#)!:the first coefficient of this elliptic curve. | | `b` | [BigInteger](https://developer.android.com/reference/kotlin/java/math/BigInteger.html#)!:the second coefficient of this elliptic curve. | | Exceptions || |--------------------------------------|------------------------------------------| | `java.lang.NullPointerException` | if`field`,`a`, or`b`is null. | | `java.lang.IllegalArgumentException` | if`a`or`b`is not null and not in`field`. | ### EllipticCurve Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels) ``` EllipticCurve(     field: ECField!,     a: BigInteger!,     b: BigInteger!,     seed: ByteArray!) ``` Creates an elliptic curve with the specified elliptic field`field`, the coefficients`a`and`b`, and the`seed`used for curve generation. | Parameters || |---------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | `field` | [ECField](https://developer.android.com/reference/kotlin/java/security/spec/ECField)!:the finite field that this elliptic curve is over. | | `a` | [BigInteger](https://developer.android.com/reference/kotlin/java/math/BigInteger.html#)!:the first coefficient of this elliptic curve. | | `b` | [BigInteger](https://developer.android.com/reference/kotlin/java/math/BigInteger.html#)!:the second coefficient of this elliptic curve. | | `seed` | [ByteArray](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-byte-array/index.html)!:the bytes used during curve generation for later validation. Contents of this array are copied to protect against subsequent modification. | | Exceptions || |--------------------------------------|------------------------------------------| | `java.lang.NullPointerException` | if`field`,`a`, or`b`is null. | | `java.lang.IllegalArgumentException` | if`a`or`b`is not null and not in`field`. | ## Public methods ### equals Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels) ``` open fun equals(other: Any?): Boolean ``` Compares this elliptic curve for equality with the specified object. | Parameters || |-------|----------------------------| | `obj` | the object to be compared. | | Return || |------------------------------------------------------------------------------------|---------------------------------------------------------------------------------------------| | [Boolean](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-boolean/index.html) | true if`obj`is an instance of EllipticCurve and the field, A, and B match, false otherwise. | ### getA Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels) ``` open fun getA(): BigInteger! ``` Returns the first coefficient`a`of the elliptic curve. | Return || |------------------------------------------------------------------------------------------|---------------------------| | [BigInteger](https://developer.android.com/reference/kotlin/java/math/BigInteger.html#)! | the first coefficient`a`. | ### getB Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels) ``` open fun getB(): BigInteger! ``` Returns the second coefficient`b`of the elliptic curve. | Return || |------------------------------------------------------------------------------------------|----------------------------| | [BigInteger](https://developer.android.com/reference/kotlin/java/math/BigInteger.html#)! | the second coefficient`b`. | ### getField Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels) ``` open fun getField(): ECField! ``` Returns the finite field`field`that this elliptic curve is over. | Return || |---------------------------------------------------------------------------------------|------------------------------------------| | [ECField](https://developer.android.com/reference/kotlin/java/security/spec/ECField)! | the field`field`that this curve is over. | ### getSeed Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels) ``` open fun getSeed(): ByteArray! ``` Returns the seeding bytes`seed`used during curve generation. May be null if not specified. | Return || |------------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------| | [ByteArray](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-byte-array/index.html)! | the seeding bytes`seed`. A new array is returned each time this method is called. | ### hashCode Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels) ``` open fun hashCode(): Int ``` Returns a hash code value for this elliptic curve. | Return || |----------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | [Int](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-int/index.html) | a hash code value computed from the hash codes of the field, A, and B, as follows: ```kotlin (field.hashCode() << 6) + (a.hashCode() << 4) + (b.hashCode() << 2) ``` |