# SecureRandomSpi Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels) # SecureRandomSpi ``` abstract class SecureRandomSpi : Serializable ``` |---|----------------------------------------------------------------------------------------------------------------| | [kotlin.Any](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-any/index.html) || | ↳ | [java.security.SecureRandomSpi](https://developer.android.com/reference/kotlin/java/security/SecureRandomSpi#) | This class defines the*Service Provider Interface* (**SPI** ) for the[SecureRandom](https://developer.android.com/reference/kotlin/java/security/SecureRandom)class. All the abstract methods in this class must be implemented by each service provider who wishes to supply the implementation of a cryptographically strong pseudo-random number generator. ## Summary | Public constructors || |--------------------------------------------------------------------------------------------------------------------------------------------------------|---| | [SecureRandomSpi](https://developer.android.com/reference/kotlin/java/security/SecureRandomSpi#SecureRandomSpi())`()` Constructor without a parameter. | | Protected constructors || |-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|---| | [SecureRandomSpi](https://developer.android.com/reference/kotlin/java/security/SecureRandomSpi#SecureRandomSpi(java.security.SecureRandomParameters))`(`params:` `[SecureRandomParameters](https://developer.android.com/reference/kotlin/java/security/SecureRandomParameters)!`)` Constructor with a parameter. | | Public methods || |--------------------------------------------------------------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | open[String](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-string/index.html) | [toString](https://developer.android.com/reference/kotlin/java/security/SecureRandomSpi#toString())`()` Returns a Human-readable string representation of this`SecureRandom`. | | Protected methods || |--------------------------------------------------------------------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | abstract[ByteArray](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-byte-array/index.html)! | [engineGenerateSeed](https://developer.android.com/reference/kotlin/java/security/SecureRandomSpi#engineGenerateSeed(kotlin.Int))`(`numBytes:` `[Int](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-int/index.html)`)` Returns the given number of seed bytes. | | open[SecureRandomParameters](https://developer.android.com/reference/kotlin/java/security/SecureRandomParameters)! | [engineGetParameters](https://developer.android.com/reference/kotlin/java/security/SecureRandomSpi#engineGetParameters())`()` Returns the effective[SecureRandomParameters](https://developer.android.com/reference/kotlin/java/security/SecureRandomParameters)for this`SecureRandom`instance. | | abstract[Unit](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-unit/index.html) | [engineNextBytes](https://developer.android.com/reference/kotlin/java/security/SecureRandomSpi#engineNextBytes(kotlin.ByteArray))`(`bytes:` `[ByteArray](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-byte-array/index.html)!`)` Generates a user-specified number of random bytes. | | open[Unit](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-unit/index.html) | [engineNextBytes](https://developer.android.com/reference/kotlin/java/security/SecureRandomSpi#engineNextBytes(kotlin.ByteArray,%20java.security.SecureRandomParameters))`(`bytes:` `[ByteArray](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-byte-array/index.html)!`, `params:` `[SecureRandomParameters](https://developer.android.com/reference/kotlin/java/security/SecureRandomParameters)!`)` Generates a user-specified number of random bytes with additional parameters. | | open[Unit](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-unit/index.html) | [engineReseed](https://developer.android.com/reference/kotlin/java/security/SecureRandomSpi#engineReseed(java.security.SecureRandomParameters))`(`params:` `[SecureRandomParameters](https://developer.android.com/reference/kotlin/java/security/SecureRandomParameters)!`)` Reseeds this random object with entropy input read from its entropy source with additional parameters. | | abstract[Unit](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-unit/index.html) | [engineSetSeed](https://developer.android.com/reference/kotlin/java/security/SecureRandomSpi#engineSetSeed(kotlin.ByteArray))`(`seed:` `[ByteArray](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-byte-array/index.html)!`)` Reseeds this random object with the given seed. | ## Public constructors ### SecureRandomSpi Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels) ``` SecureRandomSpi() ``` Constructor without a parameter. ## Protected constructors ### SecureRandomSpi Added in[API level 35](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels) ``` protected SecureRandomSpi(params: SecureRandomParameters!) ``` Constructor with a parameter. | Parameters || |----------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | `params` | [SecureRandomParameters](https://developer.android.com/reference/kotlin/java/security/SecureRandomParameters)!:the[SecureRandomParameters](https://developer.android.com/reference/kotlin/java/security/SecureRandomParameters)object. This argument can be`null`. | | Exceptions || |--------------------------------------|------------------------------------------------------------------| | `java.lang.IllegalArgumentException` | if`params`is unrecognizable or unsupported by this`SecureRandom` | ## Public methods ### toString Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels) ``` open fun toString(): String ``` Returns a Human-readable string representation of this`SecureRandom`. | Return || |----------------------------------------------------------------------------------|---------------------------| | [String](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-string/index.html) | the string representation | ## Protected methods ### engineGenerateSeed Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels) ``` protected abstract fun engineGenerateSeed(numBytes: Int): ByteArray! ``` Returns the given number of seed bytes. This call may be used to seed other random number generators. | Parameters || |------------|------------------------------------------------------------------------------------------------------------------| | `numBytes` | [Int](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-int/index.html):the number of seed bytes to generate. | | Return || |------------------------------------------------------------------------------------------|-----------------| | [ByteArray](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-byte-array/index.html)! | the seed bytes. | ### engineGetParameters Added in[API level 35](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels) ``` protected open fun engineGetParameters(): SecureRandomParameters! ``` Returns the effective[SecureRandomParameters](https://developer.android.com/reference/kotlin/java/security/SecureRandomParameters)for this`SecureRandom`instance. | Return || |----------------------------------------------------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | [SecureRandomParameters](https://developer.android.com/reference/kotlin/java/security/SecureRandomParameters)! | the effective[SecureRandomParameters](https://developer.android.com/reference/kotlin/java/security/SecureRandomParameters)parameters, or`null`if no parameters were used. | ### engineNextBytes Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels) ``` protected abstract fun engineNextBytes(bytes: ByteArray!): Unit ``` Generates a user-specified number of random bytes. Some random number generators can only generate a limited amount of random bytes per invocation. If the size of`bytes`is greater than this limit, the implementation should invoke its generation process multiple times to completely fill the buffer before returning from this method. | Parameters || |---------|---------------------------------------------------------------------------------------------------------------------------------------| | `bytes` | [ByteArray](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-byte-array/index.html)!:the array to be filled in with random bytes. | ### engineNextBytes Added in[API level 35](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels) ``` protected open fun engineNextBytes(     bytes: ByteArray!,     params: SecureRandomParameters! ): Unit ``` Generates a user-specified number of random bytes with additional parameters. Some random number generators can only generate a limited amount of random bytes per invocation. If the size of`bytes`is greater than this limit, the implementation should invoke its generation process multiple times to completely fill the buffer before returning from this method. | Parameters || |----------|--------------------------------------------------------------------------------------------------------------------------------------| | `bytes` | [ByteArray](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-byte-array/index.html)!:the array to be filled in with random bytes | | `params` | [SecureRandomParameters](https://developer.android.com/reference/kotlin/java/security/SecureRandomParameters)!:additional parameters | | Exceptions || |-------------------------------------------|------------------------------------------------------------------| | `java.lang.UnsupportedOperationException` | if the implementation has not overridden this method | | `java.lang.IllegalArgumentException` | if`params`is`null`, illegal or unsupported by this`SecureRandom` | ### engineReseed Added in[API level 35](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels) ``` protected open fun engineReseed(params: SecureRandomParameters!): Unit ``` Reseeds this random object with entropy input read from its entropy source with additional parameters. If this method is called by[SecureRandom.reseed()](https://developer.android.com/reference/kotlin/java/security/SecureRandom#reseed()),`params`will be`null`. Do not override this method if the implementation does not support reseeding. | Parameters || |----------|------------------------------------------------------------------------------------------------------------------------------------------------| | `params` | [SecureRandomParameters](https://developer.android.com/reference/kotlin/java/security/SecureRandomParameters)!:extra parameters, can be`null`. | | Exceptions || |-------------------------------------------|-----------------------------------------------------------| | `java.lang.UnsupportedOperationException` | if the implementation has not overridden this method | | `java.lang.IllegalArgumentException` | if`params`is illegal or unsupported by this`SecureRandom` | ### engineSetSeed Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element.html#ApiLevels) ``` protected abstract fun engineSetSeed(seed: ByteArray!): Unit ``` Reseeds this random object with the given seed. The seed supplements, rather than replaces, the existing seed. Thus, repeated calls are guaranteed never to reduce randomness. | Parameters || |--------|----------------------------------------------------------------------------------------------------| | `seed` | [ByteArray](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-byte-array/index.html)!:the seed. |