# SecureRandom Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) Summary:[Ctors](https://developer.android.com/reference/java/security/SecureRandom#pubctors)\|[Protected Ctors](https://developer.android.com/reference/java/security/SecureRandom#proctors)\|[Methods](https://developer.android.com/reference/java/security/SecureRandom#pubmethods)\|[Protected Methods](https://developer.android.com/reference/java/security/SecureRandom#promethods)\|[Inherited Methods](https://developer.android.com/reference/java/security/SecureRandom#inhmethods) # SecureRandom ` public class SecureRandom ` ` `` extends `[Random](https://developer.android.com/reference/java/util/Random)` `` ` |---|---|----------------------------| | [java.lang.Object](https://developer.android.com/reference/java/lang/Object) ||| | ↳ | [java.util.Random](https://developer.android.com/reference/java/util/Random) || | | ↳ | java.security.SecureRandom |
*** ** * ** *** This class provides a cryptographically strong random number generator (RNG). A cryptographically strong random number minimally complies with the statistical random number generator tests specified in[*FIPS 140-2, Security Requirements for Cryptographic Modules*](http://nvlpubs.nist.gov/nistpubs/FIPS/NIST.FIPS.140-2.pdf), section 4.9.1. Additionally,`SecureRandom`must produce non-deterministic output. Therefore any seed material passed to a`SecureRandom`object must be unpredictable, and all`SecureRandom`output sequences must be cryptographically strong, as described in[*RFC 4086: Randomness Requirements for Security*](http://tools.ietf.org/html/rfc4086). Many`SecureRandom`implementations are in the form of a pseudo-random number generator (PRNG, also known as deterministic random bits generator or DRBG), which means they use a deterministic algorithm to produce a pseudo-random sequence from a random seed. Other implementations may produce true random numbers, and yet others may use a combination of both techniques. A caller obtains a`SecureRandom`instance via the no-argument constructor or one of the`getInstance`methods. For example: > > ``` > SecureRandom r1 = new SecureRandom(); > SecureRandom r2 = SecureRandom.getInstance("NativePRNG"); > SecureRandom r3 = SecureRandom.getInstance("DRBG", > DrbgParameters.instantiation(128, RESEED_ONLY, null)); > ``` The third statement above returns a`SecureRandom`object of the specific algorithm supporting the specific instantiate parameters. The implementation's effective instantiated parameters must match this minimum request but is not necessarily the same. For example, even if the request does not require a certain feature, the actual instantiation can provide the feature. An implementation may lazily instantiate a`SecureRandom`until it's actually used, but the effective instantiate parameters must be determined right after it's created and[getParameters()](https://developer.android.com/reference/java/security/SecureRandom#getParameters())should always return the same result unchanged. Typical callers of`SecureRandom`invoke the following methods to retrieve random bytes: > > ``` > SecureRandom random = new SecureRandom(); > byte[] bytes = new byte[20]; > random.nextBytes(bytes); > ``` Callers may also invoke the[generateSeed(int)](https://developer.android.com/reference/java/security/SecureRandom#generateSeed(int))method to generate a given number of seed bytes (to seed other random number generators, for example): > > ``` > byte[] seed = random.generateSeed(20); > ``` A newly created PRNG`SecureRandom`object is not seeded (except if it is created by[SecureRandom(byte[])](https://developer.android.com/reference/java/security/SecureRandom#SecureRandom(byte[]))). The first call to`nextBytes`will force it to seed itself from an implementation- specific entropy source. This self-seeding will not occur if`setSeed`was previously called. A`SecureRandom`can be reseeded at any time by calling the`reseed`or`setSeed`method. The`reseed`method reads entropy input from its entropy source to reseed itself. The`setSeed`method requires the caller to provide the seed. Please note that`reseed`may not be supported by all`SecureRandom`implementations. Some`SecureRandom`implementations may accept a[SecureRandomParameters](https://developer.android.com/reference/java/security/SecureRandomParameters)parameter in its[nextBytes(byte[], java.security.SecureRandomParameters)](https://developer.android.com/reference/java/security/SecureRandom#nextBytes(byte[],%20java.security.SecureRandomParameters))and[reseed(java.security.SecureRandomParameters)](https://developer.android.com/reference/java/security/SecureRandom#reseed(java.security.SecureRandomParameters))methods to further control the behavior of the methods. Note: Depending on the implementation, the`generateSeed`,`reseed`and`nextBytes`methods may block as entropy is being gathered, for example, if the entropy source is /dev/random on various Unix-like operating systems. ## Thread safety `SecureRandom`objects are safe for use by multiple concurrent threads.
**See also:** - [SecureRandomSpi](https://developer.android.com/reference/java/security/SecureRandomSpi) - [Random](https://developer.android.com/reference/java/util/Random) ## Summary | ### Public constructors || |--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|---| | ` `[SecureRandom](https://developer.android.com/reference/java/security/SecureRandom#SecureRandom())`() ` Constructs a secure random number generator (RNG) implementing the default random number algorithm. | | ` `[SecureRandom](https://developer.android.com/reference/java/security/SecureRandom#SecureRandom(byte[]))`(byte[] seed) ` Constructs a secure random number generator (RNG) implementing the default random number algorithm. | | ### Protected constructors || |--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|---| | ` `[SecureRandom](https://developer.android.com/reference/java/security/SecureRandom#SecureRandom(java.security.SecureRandomSpi,%20java.security.Provider))`(`[SecureRandomSpi](https://developer.android.com/reference/java/security/SecureRandomSpi)` secureRandomSpi, `[Provider](https://developer.android.com/reference/java/security/Provider)` provider) ` Creates a`SecureRandom`object. | | ### Public methods || |-----------------------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | ` byte[]` | ` `[generateSeed](https://developer.android.com/reference/java/security/SecureRandom#generateSeed(int))`(int numBytes) ` Returns the given number of seed bytes, computed using the seed generation algorithm that this class uses to seed itself. | | ` `[String](https://developer.android.com/reference/java/lang/String) | ` `[getAlgorithm](https://developer.android.com/reference/java/security/SecureRandom#getAlgorithm())`() ` Returns the name of the algorithm implemented by this`SecureRandom`object. | | ` static `[SecureRandom](https://developer.android.com/reference/java/security/SecureRandom) | ` `[getInstance](https://developer.android.com/reference/java/security/SecureRandom#getInstance(java.lang.String))`(`[String](https://developer.android.com/reference/java/lang/String)` algorithm) ` Returns a`SecureRandom`object that implements the specified Random Number Generator (RNG) algorithm. | | ` static `[SecureRandom](https://developer.android.com/reference/java/security/SecureRandom) | ` `[getInstance](https://developer.android.com/reference/java/security/SecureRandom#getInstance(java.lang.String,%20java.lang.String))`(`[String](https://developer.android.com/reference/java/lang/String)` algorithm, `[String](https://developer.android.com/reference/java/lang/String)` provider) ` Returns a`SecureRandom`object that implements the specified Random Number Generator (RNG) algorithm. | | ` static `[SecureRandom](https://developer.android.com/reference/java/security/SecureRandom) | ` `[getInstance](https://developer.android.com/reference/java/security/SecureRandom#getInstance(java.lang.String,%20java.security.SecureRandomParameters))`(`[String](https://developer.android.com/reference/java/lang/String)` algorithm, `[SecureRandomParameters](https://developer.android.com/reference/java/security/SecureRandomParameters)` params) ` Returns a`SecureRandom`object that implements the specified Random Number Generator (RNG) algorithm and supports the specified`SecureRandomParameters`request. | | ` static `[SecureRandom](https://developer.android.com/reference/java/security/SecureRandom) | ` `[getInstance](https://developer.android.com/reference/java/security/SecureRandom#getInstance(java.lang.String,%20java.security.Provider))`(`[String](https://developer.android.com/reference/java/lang/String)` algorithm, `[Provider](https://developer.android.com/reference/java/security/Provider)` provider) ` Returns a`SecureRandom`object that implements the specified Random Number Generator (RNG) algorithm. | | ` static `[SecureRandom](https://developer.android.com/reference/java/security/SecureRandom) | ` `[getInstance](https://developer.android.com/reference/java/security/SecureRandom#getInstance(java.lang.String,%20java.security.SecureRandomParameters,%20java.lang.String))`(`[String](https://developer.android.com/reference/java/lang/String)` algorithm, `[SecureRandomParameters](https://developer.android.com/reference/java/security/SecureRandomParameters)` params, `[String](https://developer.android.com/reference/java/lang/String)` provider) ` Returns a`SecureRandom`object that implements the specified Random Number Generator (RNG) algorithm and supports the specified`SecureRandomParameters`request. | | ` static `[SecureRandom](https://developer.android.com/reference/java/security/SecureRandom) | ` `[getInstance](https://developer.android.com/reference/java/security/SecureRandom#getInstance(java.lang.String,%20java.security.SecureRandomParameters,%20java.security.Provider))`(`[String](https://developer.android.com/reference/java/lang/String)` algorithm, `[SecureRandomParameters](https://developer.android.com/reference/java/security/SecureRandomParameters)` params, `[Provider](https://developer.android.com/reference/java/security/Provider)` provider) ` Returns a`SecureRandom`object that implements the specified Random Number Generator (RNG) algorithm and supports the specified`SecureRandomParameters`request. | | ` static `[SecureRandom](https://developer.android.com/reference/java/security/SecureRandom) | ` `[getInstanceStrong](https://developer.android.com/reference/java/security/SecureRandom#getInstanceStrong())`() ` Returns a`SecureRandom`object. | | ` `[SecureRandomParameters](https://developer.android.com/reference/java/security/SecureRandomParameters) | ` `[getParameters](https://developer.android.com/reference/java/security/SecureRandom#getParameters())`() ` Returns the effective[SecureRandomParameters](https://developer.android.com/reference/java/security/SecureRandomParameters)for this`SecureRandom`instance. | | ` final `[Provider](https://developer.android.com/reference/java/security/Provider) | ` `[getProvider](https://developer.android.com/reference/java/security/SecureRandom#getProvider())`() ` Returns the provider of this`SecureRandom`object. | | ` static byte[]` | ` `[getSeed](https://developer.android.com/reference/java/security/SecureRandom#getSeed(int))`(int numBytes) ` Returns the given number of seed bytes, computed using the seed generation algorithm that this class uses to seed itself. | | ` void` | ` `[nextBytes](https://developer.android.com/reference/java/security/SecureRandom#nextBytes(byte[],%20java.security.SecureRandomParameters))`(byte[] bytes, `[SecureRandomParameters](https://developer.android.com/reference/java/security/SecureRandomParameters)` params) ` Generates a user-specified number of random bytes with additional parameters. | | ` void` | ` `[nextBytes](https://developer.android.com/reference/java/security/SecureRandom#nextBytes(byte[]))`(byte[] bytes) ` Generates a user-specified number of random bytes. | | ` void` | ` `[reseed](https://developer.android.com/reference/java/security/SecureRandom#reseed(java.security.SecureRandomParameters))`(`[SecureRandomParameters](https://developer.android.com/reference/java/security/SecureRandomParameters)` params) ` Reseeds this`SecureRandom`with entropy input read from its entropy source with additional parameters. | | ` void` | ` `[reseed](https://developer.android.com/reference/java/security/SecureRandom#reseed())`() ` Reseeds this`SecureRandom`with entropy input read from its entropy source. | | ` void` | ` `[setSeed](https://developer.android.com/reference/java/security/SecureRandom#setSeed(long))`(long seed) ` Reseeds this random object, using the eight bytes contained in the given`long seed`. | | ` void` | ` `[setSeed](https://developer.android.com/reference/java/security/SecureRandom#setSeed(byte[]))`(byte[] seed) ` Reseeds this random object with the given seed. | | ` `[String](https://developer.android.com/reference/java/lang/String) | ` `[toString](https://developer.android.com/reference/java/security/SecureRandom#toString())`() ` Returns a Human-readable string representation of this`SecureRandom`. | | ### Protected methods || |--------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | ` final int` | ` `[next](https://developer.android.com/reference/java/security/SecureRandom#next(int))`(int numBits) ` Generates an integer containing the user-specified number of pseudo-random bits (right justified, with leading zeros). | | ### Inherited methods | |-----------------------|---| | From class` `[java.util.Random](https://developer.android.com/reference/java/util/Random)` ` |------------------------------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | ` `[DoubleStream](https://developer.android.com/reference/java/util/stream/DoubleStream) | ` `[doubles](https://developer.android.com/reference/java/util/Random#doubles(long))`(long streamSize) ` Returns a stream producing the given`streamSize`number of pseudorandom`double`values, each between zero (inclusive) and one (exclusive). | | ` `[DoubleStream](https://developer.android.com/reference/java/util/stream/DoubleStream) | ` `[doubles](https://developer.android.com/reference/java/util/Random#doubles())`() ` Returns an effectively unlimited stream of pseudorandom`double`values, each between zero (inclusive) and one (exclusive). | | ` `[DoubleStream](https://developer.android.com/reference/java/util/stream/DoubleStream) | ` `[doubles](https://developer.android.com/reference/java/util/Random#doubles(double,%20double))`(double randomNumberOrigin, double randomNumberBound) ` Returns an effectively unlimited stream of pseudorandom`double`values, each conforming to the given origin (inclusive) and bound (exclusive). | | ` `[DoubleStream](https://developer.android.com/reference/java/util/stream/DoubleStream) | ` `[doubles](https://developer.android.com/reference/java/util/Random#doubles(long,%20double,%20double))`(long streamSize, double randomNumberOrigin, double randomNumberBound) ` Returns a stream producing the given`streamSize`number of pseudorandom`double`values, each conforming to the given origin (inclusive) and bound (exclusive). | | ` static `[Random](https://developer.android.com/reference/java/util/Random) | ` `[from](https://developer.android.com/reference/java/util/Random#from(java.util.random.RandomGenerator))`(`[RandomGenerator](https://developer.android.com/reference/java/util/random/RandomGenerator)` generator) ` Returns an instance of`Random`that delegates method calls to the[RandomGenerator](https://developer.android.com/reference/java/util/random/RandomGenerator)argument. | | ` `[IntStream](https://developer.android.com/reference/java/util/stream/IntStream) | ` `[ints](https://developer.android.com/reference/java/util/Random#ints(long))`(long streamSize) ` Returns a stream producing the given`streamSize`number of pseudorandom`int`values. | | ` `[IntStream](https://developer.android.com/reference/java/util/stream/IntStream) | ` `[ints](https://developer.android.com/reference/java/util/Random#ints(int,%20int))`(int randomNumberOrigin, int randomNumberBound) ` Returns an effectively unlimited stream of pseudorandom`int`values, each conforming to the given origin (inclusive) and bound (exclusive). | | ` `[IntStream](https://developer.android.com/reference/java/util/stream/IntStream) | ` `[ints](https://developer.android.com/reference/java/util/Random#ints(long,%20int,%20int))`(long streamSize, int randomNumberOrigin, int randomNumberBound) ` Returns a stream producing the given`streamSize`number of pseudorandom`int`values, each conforming to the given origin (inclusive) and bound (exclusive). | | ` `[IntStream](https://developer.android.com/reference/java/util/stream/IntStream) | ` `[ints](https://developer.android.com/reference/java/util/Random#ints())`() ` Returns an effectively unlimited stream of pseudorandom`int`values. | | ` `[LongStream](https://developer.android.com/reference/java/util/stream/LongStream) | ` `[longs](https://developer.android.com/reference/java/util/Random#longs())`() ` Returns an effectively unlimited stream of pseudorandom`long`values. | | ` `[LongStream](https://developer.android.com/reference/java/util/stream/LongStream) | ` `[longs](https://developer.android.com/reference/java/util/Random#longs(long))`(long streamSize) ` Returns a stream producing the given`streamSize`number of pseudorandom`long`values. | | ` `[LongStream](https://developer.android.com/reference/java/util/stream/LongStream) | ` `[longs](https://developer.android.com/reference/java/util/Random#longs(long,%20long))`(long randomNumberOrigin, long randomNumberBound) ` Returns an effectively unlimited stream of pseudorandom`long`values, each conforming to the given origin (inclusive) and bound (exclusive). | | ` `[LongStream](https://developer.android.com/reference/java/util/stream/LongStream) | ` `[longs](https://developer.android.com/reference/java/util/Random#longs(long,%20long,%20long))`(long streamSize, long randomNumberOrigin, long randomNumberBound) ` Returns a stream producing the given`streamSize`number of pseudorandom`long`, each conforming to the given origin (inclusive) and bound (exclusive). | | ` int` | ` `[next](https://developer.android.com/reference/java/util/Random#next(int))`(int bits) ` Generates the next pseudorandom number. | | ` boolean` | ` `[nextBoolean](https://developer.android.com/reference/java/util/Random#nextBoolean())`() ` Returns the next pseudorandom, uniformly distributed`boolean`value from this random number generator's sequence. | | ` void` | ` `[nextBytes](https://developer.android.com/reference/java/util/Random#nextBytes(byte[]))`(byte[] bytes) ` Generates random bytes and places them into a user-supplied byte array. | | ` double` | ` `[nextDouble](https://developer.android.com/reference/java/util/Random#nextDouble())`() ` Returns the next pseudorandom, uniformly distributed`double`value between`0.0`and`1.0`from this random number generator's sequence. | | ` float` | ` `[nextFloat](https://developer.android.com/reference/java/util/Random#nextFloat())`() ` Returns the next pseudorandom, uniformly distributed`float`value between`0.0`and`1.0`from this random number generator's sequence. | | ` double` | ` `[nextGaussian](https://developer.android.com/reference/java/util/Random#nextGaussian())`() ` Returns the next pseudorandom, Gaussian ("normally") distributed`double`value with mean`0.0`and standard deviation`1.0`from this random number generator's sequence. | | ` int` | ` `[nextInt](https://developer.android.com/reference/java/util/Random#nextInt())`() ` Returns the next pseudorandom, uniformly distributed`int`value from this random number generator's sequence. | | ` int` | ` `[nextInt](https://developer.android.com/reference/java/util/Random#nextInt(int))`(int bound) ` Returns a pseudorandom, uniformly distributed`int`value between 0 (inclusive) and the specified value (exclusive), drawn from this random number generator's sequence. | | ` long` | ` `[nextLong](https://developer.android.com/reference/java/util/Random#nextLong())`() ` Returns the next pseudorandom, uniformly distributed`long`value from this random number generator's sequence. | | ` void` | ` `[setSeed](https://developer.android.com/reference/java/util/Random#setSeed(long))`(long seed) ` Sets or updates the seed of this random number generator using the provided`long`seed value (optional operation). | || | From class` `[java.lang.Object](https://developer.android.com/reference/java/lang/Object)` ` |--------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | ` `[Object](https://developer.android.com/reference/java/lang/Object) | ` `[clone](https://developer.android.com/reference/java/lang/Object#clone())`() ` Creates and returns a copy of this object. | | ` boolean` | ` `[equals](https://developer.android.com/reference/java/lang/Object#equals(java.lang.Object))`(`[Object](https://developer.android.com/reference/java/lang/Object)` obj) ` Indicates whether some other object is "equal to" this one. | | ` void` | ` `[finalize](https://developer.android.com/reference/java/lang/Object#finalize())`() ` Called by the garbage collector on an object when garbage collection determines that there are no more references to the object. | | ` final `[Class](https://developer.android.com/reference/java/lang/Class)`` | ` `[getClass](https://developer.android.com/reference/java/lang/Object#getClass())`() ` Returns the runtime class of this`Object`. | | ` int` | ` `[hashCode](https://developer.android.com/reference/java/lang/Object#hashCode())`() ` Returns a hash code value for the object. | | ` final void` | ` `[notify](https://developer.android.com/reference/java/lang/Object#notify())`() ` Wakes up a single thread that is waiting on this object's monitor. | | ` final void` | ` `[notifyAll](https://developer.android.com/reference/java/lang/Object#notifyAll())`() ` Wakes up all threads that are waiting on this object's monitor. | | ` `[String](https://developer.android.com/reference/java/lang/String) | ` `[toString](https://developer.android.com/reference/java/lang/Object#toString())`() ` Returns a string representation of the object. | | ` final void` | ` `[wait](https://developer.android.com/reference/java/lang/Object#wait(long,%20int))`(long timeoutMillis, int nanos) ` Causes the current thread to wait until it is awakened, typically by being*notified* or*interrupted*, or until a certain amount of real time has elapsed. | | ` final void` | ` `[wait](https://developer.android.com/reference/java/lang/Object#wait(long))`(long timeoutMillis) ` Causes the current thread to wait until it is awakened, typically by being*notified* or*interrupted*, or until a certain amount of real time has elapsed. | | ` final void` | ` `[wait](https://developer.android.com/reference/java/lang/Object#wait())`() ` Causes the current thread to wait until it is awakened, typically by being*notified* or*interrupted*. | || | From interface` `[java.util.random.RandomGenerator](https://developer.android.com/reference/java/util/random/RandomGenerator)` ` |-------------------------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | ` default `[DoubleStream](https://developer.android.com/reference/java/util/stream/DoubleStream) | ` `[doubles](https://developer.android.com/reference/java/util/random/RandomGenerator#doubles(long,%20double,%20double))`(long streamSize, double randomNumberOrigin, double randomNumberBound) ` Returns a stream producing the given`streamSize`number of pseudorandomly chosen`double`values, where each value is between the specified origin (inclusive) and the specified bound (exclusive). | | ` default `[DoubleStream](https://developer.android.com/reference/java/util/stream/DoubleStream) | ` `[doubles](https://developer.android.com/reference/java/util/random/RandomGenerator#doubles(long))`(long streamSize) ` Returns a stream producing the given`streamSize`number of pseudorandomly chosen`double`values. | | ` default `[DoubleStream](https://developer.android.com/reference/java/util/stream/DoubleStream) | ` `[doubles](https://developer.android.com/reference/java/util/random/RandomGenerator#doubles())`() ` Returns an effectively unlimited stream of pseudorandomly chosen`double`values. | | ` default `[DoubleStream](https://developer.android.com/reference/java/util/stream/DoubleStream) | ` `[doubles](https://developer.android.com/reference/java/util/random/RandomGenerator#doubles(double,%20double))`(double randomNumberOrigin, double randomNumberBound) ` Returns an effectively unlimited stream of pseudorandomly chosen`double`values, where each value is between the specified origin (inclusive) and the specified bound (exclusive). | | ` static `[RandomGenerator](https://developer.android.com/reference/java/util/random/RandomGenerator) | ` `[getDefault](https://developer.android.com/reference/java/util/random/RandomGenerator#getDefault())`() ` Returns a[RandomGenerator](https://developer.android.com/reference/java/util/random/RandomGenerator)meeting the minimal requirement of having an[algorithm](https://developer.android.com/reference/java/security/package-summary#algorithms)whose state bits are greater than or equal 64. | | ` default `[IntStream](https://developer.android.com/reference/java/util/stream/IntStream) | ` `[ints](https://developer.android.com/reference/java/util/random/RandomGenerator#ints(long))`(long streamSize) ` Returns a stream producing the given`streamSize`number of pseudorandomly chosen`int`values. | | ` default `[IntStream](https://developer.android.com/reference/java/util/stream/IntStream) | ` `[ints](https://developer.android.com/reference/java/util/random/RandomGenerator#ints(int,%20int))`(int randomNumberOrigin, int randomNumberBound) ` Returns an effectively unlimited stream of pseudorandomly chosen`int`values, where each value is between the specified origin (inclusive) and the specified bound (exclusive). | | ` default `[IntStream](https://developer.android.com/reference/java/util/stream/IntStream) | ` `[ints](https://developer.android.com/reference/java/util/random/RandomGenerator#ints())`() ` Returns an effectively unlimited stream of pseudorandomly chosen`int`values. | | ` default `[IntStream](https://developer.android.com/reference/java/util/stream/IntStream) | ` `[ints](https://developer.android.com/reference/java/util/random/RandomGenerator#ints(long,%20int,%20int))`(long streamSize, int randomNumberOrigin, int randomNumberBound) ` Returns a stream producing the given`streamSize`number of pseudorandomly chosen`int`values, where each value is between the specified origin (inclusive) and the specified bound (exclusive). | | ` default boolean` | ` `[isDeprecated](https://developer.android.com/reference/java/util/random/RandomGenerator#isDeprecated())`() ` Return true if the implementation of RandomGenerator (algorithm) has been marked for deprecation. | | ` default `[LongStream](https://developer.android.com/reference/java/util/stream/LongStream) | ` `[longs](https://developer.android.com/reference/java/util/random/RandomGenerator#longs(long))`(long streamSize) ` Returns a stream producing the given`streamSize`number of pseudorandomly chosen`long`values. | | ` default `[LongStream](https://developer.android.com/reference/java/util/stream/LongStream) | ` `[longs](https://developer.android.com/reference/java/util/random/RandomGenerator#longs())`() ` Returns an effectively unlimited stream of pseudorandomly chosen`long`values. | | ` default `[LongStream](https://developer.android.com/reference/java/util/stream/LongStream) | ` `[longs](https://developer.android.com/reference/java/util/random/RandomGenerator#longs(long,%20long))`(long randomNumberOrigin, long randomNumberBound) ` Returns an effectively unlimited stream of pseudorandomly chosen`long`values, where each value is between the specified origin (inclusive) and the specified bound (exclusive). | | ` default `[LongStream](https://developer.android.com/reference/java/util/stream/LongStream) | ` `[longs](https://developer.android.com/reference/java/util/random/RandomGenerator#longs(long,%20long,%20long))`(long streamSize, long randomNumberOrigin, long randomNumberBound) ` Returns a stream producing the given`streamSize`number of pseudorandomly chosen`long`values, where each value is between the specified origin (inclusive) and the specified bound (exclusive). | | ` default boolean` | ` `[nextBoolean](https://developer.android.com/reference/java/util/random/RandomGenerator#nextBoolean())`() ` Returns a pseudorandomly chosen`boolean`value. | | ` default void` | ` `[nextBytes](https://developer.android.com/reference/java/util/random/RandomGenerator#nextBytes(byte[]))`(byte[] bytes) ` Fills a user-supplied byte array with generated byte values pseudorandomly chosen uniformly from the range of values between -128 (inclusive) and 127 (inclusive). | | ` default double` | ` `[nextDouble](https://developer.android.com/reference/java/util/random/RandomGenerator#nextDouble())`() ` Returns a pseudorandom`double`value between zero (inclusive) and one (exclusive). | | ` default double` | ` `[nextDouble](https://developer.android.com/reference/java/util/random/RandomGenerator#nextDouble(double))`(double bound) ` Returns a pseudorandomly chosen`double`value between zero (inclusive) and the specified bound (exclusive). | | ` default double` | ` `[nextDouble](https://developer.android.com/reference/java/util/random/RandomGenerator#nextDouble(double,%20double))`(double origin, double bound) ` Returns a pseudorandomly chosen`double`value between the specified origin (inclusive) and the specified bound (exclusive). | | ` default double` | ` `[nextExponential](https://developer.android.com/reference/java/util/random/RandomGenerator#nextExponential())`() ` Returns a nonnegative`double`value pseudorandomly chosen from an exponential distribution whose mean is 1. | | ` default float` | ` `[nextFloat](https://developer.android.com/reference/java/util/random/RandomGenerator#nextFloat(float,%20float))`(float origin, float bound) ` Returns a pseudorandomly chosen`float`value between the specified origin (inclusive) and the specified bound (exclusive). | | ` default float` | ` `[nextFloat](https://developer.android.com/reference/java/util/random/RandomGenerator#nextFloat())`() ` Returns a pseudorandom`float`value between zero (inclusive) and one (exclusive). | | ` default float` | ` `[nextFloat](https://developer.android.com/reference/java/util/random/RandomGenerator#nextFloat(float))`(float bound) ` Returns a pseudorandomly chosen`float`value between zero (inclusive) and the specified bound (exclusive). | | ` default double` | ` `[nextGaussian](https://developer.android.com/reference/java/util/random/RandomGenerator#nextGaussian(double,%20double))`(double mean, double stddev) ` Returns a`double`value pseudorandomly chosen from a Gaussian (normal) distribution with a mean and standard deviation specified by the arguments. | | ` default double` | ` `[nextGaussian](https://developer.android.com/reference/java/util/random/RandomGenerator#nextGaussian())`() ` Returns a`double`value pseudorandomly chosen from a Gaussian (normal) distribution whose mean is 0 and whose standard deviation is 1. | | ` default int` | ` `[nextInt](https://developer.android.com/reference/java/util/random/RandomGenerator#nextInt(int,%20int))`(int origin, int bound) ` Returns a pseudorandomly chosen`int`value between the specified origin (inclusive) and the specified bound (exclusive). | | ` default int` | ` `[nextInt](https://developer.android.com/reference/java/util/random/RandomGenerator#nextInt())`() ` Returns a pseudorandomly chosen`int`value. | | ` default int` | ` `[nextInt](https://developer.android.com/reference/java/util/random/RandomGenerator#nextInt(int))`(int bound) ` Returns a pseudorandomly chosen`int`value between zero (inclusive) and the specified bound (exclusive). | | ` default long` | ` `[nextLong](https://developer.android.com/reference/java/util/random/RandomGenerator#nextLong(long,%20long))`(long origin, long bound) ` Returns a pseudorandomly chosen`long`value between the specified origin (inclusive) and the specified bound (exclusive). | | ` default long` | ` `[nextLong](https://developer.android.com/reference/java/util/random/RandomGenerator#nextLong(long))`(long bound) ` Returns a pseudorandomly chosen`long`value between zero (inclusive) and the specified bound (exclusive). | | ` abstract long` | ` `[nextLong](https://developer.android.com/reference/java/util/random/RandomGenerator#nextLong())`() ` Returns a pseudorandomly chosen`long`value. | | ` static `[RandomGenerator](https://developer.android.com/reference/java/util/random/RandomGenerator) | ` `[of](https://developer.android.com/reference/java/util/random/RandomGenerator#of(java.lang.String))`(`[String](https://developer.android.com/reference/java/lang/String)` name) ` Returns an instance of[RandomGenerator](https://developer.android.com/reference/java/util/random/RandomGenerator)that utilizes the`name`[algorithm](https://developer.android.com/reference/java/security/package-summary#algorithms). | || ## Public constructors ### SecureRandom Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public SecureRandom () ``` Constructs a secure random number generator (RNG) implementing the default random number algorithm. This constructor traverses the list of registered security Providers, starting with the most preferred Provider. A new`SecureRandom`object encapsulating the`SecureRandomSpi`implementation from the first Provider that supports a`SecureRandom`(RNG) algorithm is returned. If none of the Providers support a RNG algorithm, then an implementation-specific default is returned. Note that the list of registered providers may be retrieved via the[Security.getProviders()](https://developer.android.com/reference/java/security/Security#getProviders())method. See the`SecureRandom`section in the[Java Security Standard Algorithm Names Specification](https://docs.oracle.com/en/java/javase/17/docs/specs/security/standard-names.html#securerandom-number-generation-algorithms)for information about standard RNG algorithm names.
### SecureRandom Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public SecureRandom (byte[] seed) ``` Constructs a secure random number generator (RNG) implementing the default random number algorithm. The`SecureRandom`instance is seeded with the specified seed bytes. This constructor traverses the list of registered security Providers, starting with the most preferred Provider. A new`SecureRandom`object encapsulating the`SecureRandomSpi`implementation from the first Provider that supports a`SecureRandom`(RNG) algorithm is returned. If none of the Providers support a RNG algorithm, then an implementation-specific default is returned. Note that the list of registered providers may be retrieved via the[Security.getProviders()](https://developer.android.com/reference/java/security/Security#getProviders())method. See the`SecureRandom`section in the[Java Security Standard Algorithm Names Specification](https://docs.oracle.com/en/java/javase/17/docs/specs/security/standard-names.html#securerandom-number-generation-algorithms)for information about standard RNG algorithm names.
| Parameters || |--------|--------------------------| | `seed` | `byte`: the seed.
| ## Protected constructors ### SecureRandom Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` protected SecureRandom (SecureRandomSpi secureRandomSpi, Provider provider) ``` Creates a`SecureRandom`object.
| Parameters || |-------------------|------------------------------------------------------------| | `secureRandomSpi` | `SecureRandomSpi`: the`SecureRandom`implementation.
| | `provider` | `Provider`: the provider.
| ## Public methods ### generateSeed Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public byte[] generateSeed (int numBytes) ``` Returns the given number of seed bytes, computed using the seed generation algorithm that this class uses to seed itself. This call may be used to seed other random number generators.
| Parameters || |------------|-----------------------------------------------------| | `numBytes` | `int`: the number of seed bytes to generate.
| | Returns || |----------|------------------------| | `byte[]` | the seed bytes.
| | Throws || |--------------------------------------------------------------------------------------------------------|-------------------------| | [IllegalArgumentException](https://developer.android.com/reference/java/lang/IllegalArgumentException) | if`numBytes`is negative | ### getAlgorithm Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public String getAlgorithm () ``` Returns the name of the algorithm implemented by this`SecureRandom`object.
| Returns || |--------------------------------------------------------------------|-----------------------------------------------------------------------------------------| | [String](https://developer.android.com/reference/java/lang/String) | the name of the algorithm or`unknown`if the algorithm name cannot be determined.
| ### getInstance Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public static SecureRandom getInstance (String algorithm) ``` Returns a`SecureRandom`object that implements the specified Random Number Generator (RNG) algorithm. This method traverses the list of registered security Providers, starting with the most preferred Provider. A new`SecureRandom`object encapsulating the`SecureRandomSpi`implementation from the first Provider that supports the specified algorithm is returned. Note that the list of registered providers may be retrieved via the[Security.getProviders()](https://developer.android.com/reference/java/security/Security#getProviders())method.
##### Implementation Note: - The JDK Reference Implementation additionally uses the`jdk.security.provider.preferred`[Security](https://developer.android.com/reference/java/security/Security#getProperty(java.lang.String))property to determine the preferred provider order for the specified algorithm. This may be different than the order of providers returned by[Security.getProviders()](https://developer.android.com/reference/java/security/Security#getProviders()). | Parameters || |-------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | `algorithm` | `String`: the name of the RNG algorithm. See the`SecureRandom`section in the[Java Security Standard Algorithm Names Specification](https://docs.oracle.com/en/java/javase/17/docs/specs/security/standard-names.html#securerandom-number-generation-algorithms)for information about standard RNG algorithm names.
| | Returns || |------------------------------------------------------------------------------------|------------------------------------| | [SecureRandom](https://developer.android.com/reference/java/security/SecureRandom) | the new`SecureRandom`object
| | Throws || |------------------------------------------------------------------------------------------------------------|--------------------------------------------------------------------------------------| | [NoSuchAlgorithmException](https://developer.android.com/reference/java/security/NoSuchAlgorithmException) | if no`Provider`supports a`SecureRandomSpi`implementation for the specified algorithm | | [NullPointerException](https://developer.android.com/reference/java/lang/NullPointerException) | if`algorithm`is`null` | **See also:** - [Provider](https://developer.android.com/reference/java/security/Provider) ### getInstance Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public static SecureRandom getInstance (String algorithm, String provider) ``` Returns a`SecureRandom`object that implements the specified Random Number Generator (RNG) algorithm. A new`SecureRandom`object encapsulating the`SecureRandomSpi`implementation from the specified provider is returned. The specified provider must be registered in the security provider list. Note that the list of registered providers may be retrieved via the[Security.getProviders()](https://developer.android.com/reference/java/security/Security#getProviders())method.
| Parameters || |-------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | `algorithm` | `String`: the name of the RNG algorithm. See the`SecureRandom`section in the[Java Security Standard Algorithm Names Specification](https://docs.oracle.com/en/java/javase/17/docs/specs/security/standard-names.html#securerandom-number-generation-algorithms)for information about standard RNG algorithm names.
| | `provider` | `String`: the name of the provider.
| | Returns || |------------------------------------------------------------------------------------|------------------------------------| | [SecureRandom](https://developer.android.com/reference/java/security/SecureRandom) | the new`SecureRandom`object
| | Throws || |------------------------------------------------------------------------------------------------------------|--------------------------------------------------------------------------------------------------------------| | [IllegalArgumentException](https://developer.android.com/reference/java/lang/IllegalArgumentException) | if the provider name is`null`or empty | | [NoSuchAlgorithmException](https://developer.android.com/reference/java/security/NoSuchAlgorithmException) | if a`SecureRandomSpi`implementation for the specified algorithm is not available from the specified provider | | [NoSuchProviderException](https://developer.android.com/reference/java/security/NoSuchProviderException) | if the specified provider is not registered in the security provider list | | [NullPointerException](https://developer.android.com/reference/java/lang/NullPointerException) | if`algorithm`is`null` | **See also:** - [Provider](https://developer.android.com/reference/java/security/Provider) ### getInstance Added in[API level 35](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public static SecureRandom getInstance (String algorithm, SecureRandomParameters params) ``` Returns a`SecureRandom`object that implements the specified Random Number Generator (RNG) algorithm and supports the specified`SecureRandomParameters`request. This method traverses the list of registered security Providers, starting with the most preferred Provider. A new`SecureRandom`object encapsulating the`SecureRandomSpi`implementation from the first Provider that supports the specified algorithm and the specified`SecureRandomParameters`is returned. Note that the list of registered providers may be retrieved via the[Security.getProviders()](https://developer.android.com/reference/java/security/Security#getProviders())method.
##### Implementation Note: - The JDK Reference Implementation additionally uses the`jdk.security.provider.preferred`property to determine the preferred provider order for the specified algorithm. This may be different than the order of providers returned by[Security.getProviders()](https://developer.android.com/reference/java/security/Security#getProviders()). | Parameters || |-------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | `algorithm` | `String`: the name of the RNG algorithm. See the`SecureRandom`section in the[Java Security Standard Algorithm Names Specification](https://docs.oracle.com/en/java/javase/17/docs/specs/security/standard-names.html#securerandom-number-generation-algorithms)for information about standard RNG algorithm names.
| | `params` | `SecureRandomParameters`: the`SecureRandomParameters`the newly created`SecureRandom`object must support.
| | Returns || |------------------------------------------------------------------------------------|------------------------------------| | [SecureRandom](https://developer.android.com/reference/java/security/SecureRandom) | the new`SecureRandom`object
| | Throws || |------------------------------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------| | [IllegalArgumentException](https://developer.android.com/reference/java/lang/IllegalArgumentException) | if the specified params is`null` | | [NoSuchAlgorithmException](https://developer.android.com/reference/java/security/NoSuchAlgorithmException) | if no Provider supports a`SecureRandomSpi`implementation for the specified algorithm and parameters | | [NullPointerException](https://developer.android.com/reference/java/lang/NullPointerException) | if`algorithm`is`null` | **See also:** - [Provider](https://developer.android.com/reference/java/security/Provider) ### getInstance Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public static SecureRandom getInstance (String algorithm, Provider provider) ``` Returns a`SecureRandom`object that implements the specified Random Number Generator (RNG) algorithm. A new`SecureRandom`object encapsulating the`SecureRandomSpi`implementation from the specified`Provider`object is returned. Note that the specified`Provider`object does not have to be registered in the provider list.
| Parameters || |-------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | `algorithm` | `String`: the name of the RNG algorithm. See the`SecureRandom`section in the[Java Security Standard Algorithm Names Specification](https://docs.oracle.com/en/java/javase/17/docs/specs/security/standard-names.html#securerandom-number-generation-algorithms)for information about standard RNG algorithm names.
| | `provider` | `Provider`: the provider.
| | Returns || |------------------------------------------------------------------------------------|------------------------------------| | [SecureRandom](https://developer.android.com/reference/java/security/SecureRandom) | the new`SecureRandom`object
| | Throws || |------------------------------------------------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------| | [IllegalArgumentException](https://developer.android.com/reference/java/lang/IllegalArgumentException) | if the specified provider is`null` | | [NoSuchAlgorithmException](https://developer.android.com/reference/java/security/NoSuchAlgorithmException) | if a`SecureRandomSpi`implementation for the specified algorithm is not available from the specified`Provider`object | | [NullPointerException](https://developer.android.com/reference/java/lang/NullPointerException) | if`algorithm`is`null` | **See also:** - [Provider](https://developer.android.com/reference/java/security/Provider) ### getInstance Added in[API level 35](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public static SecureRandom getInstance (String algorithm, SecureRandomParameters params, String provider) ``` Returns a`SecureRandom`object that implements the specified Random Number Generator (RNG) algorithm and supports the specified`SecureRandomParameters`request. A new`SecureRandom`object encapsulating the`SecureRandomSpi`implementation from the specified provider is returned. The specified provider must be registered in the security provider list. Note that the list of registered providers may be retrieved via the[Security.getProviders()](https://developer.android.com/reference/java/security/Security#getProviders())method.
| Parameters || |-------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | `algorithm` | `String`: the name of the RNG algorithm. See the`SecureRandom`section in the[Java Security Standard Algorithm Names Specification](https://docs.oracle.com/en/java/javase/17/docs/specs/security/standard-names.html#securerandom-number-generation-algorithms)for information about standard RNG algorithm names.
| | `params` | `SecureRandomParameters`: the`SecureRandomParameters`the newly created`SecureRandom`object must support.
| | `provider` | `String`: the name of the provider.
| | Returns || |------------------------------------------------------------------------------------|------------------------------------| | [SecureRandom](https://developer.android.com/reference/java/security/SecureRandom) | the new`SecureRandom`object
| | Throws || |------------------------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------| | [IllegalArgumentException](https://developer.android.com/reference/java/lang/IllegalArgumentException) | if the provider name is`null`or empty, or params is`null` | | [NoSuchAlgorithmException](https://developer.android.com/reference/java/security/NoSuchAlgorithmException) | if the specified provider does not support a`SecureRandomSpi`implementation for the specified algorithm and parameters | | [NoSuchProviderException](https://developer.android.com/reference/java/security/NoSuchProviderException) | if the specified provider is not registered in the security provider list | | [NullPointerException](https://developer.android.com/reference/java/lang/NullPointerException) | if`algorithm`is`null` | **See also:** - [Provider](https://developer.android.com/reference/java/security/Provider) ### getInstance Added in[API level 35](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public static SecureRandom getInstance (String algorithm, SecureRandomParameters params, Provider provider) ``` Returns a`SecureRandom`object that implements the specified Random Number Generator (RNG) algorithm and supports the specified`SecureRandomParameters`request. A new`SecureRandom`object encapsulating the`SecureRandomSpi`implementation from the specified`Provider`object is returned. Note that the specified`Provider`object does not have to be registered in the provider list.
| Parameters || |-------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | `algorithm` | `String`: the name of the RNG algorithm. See the`SecureRandom`section in the[Java Security Standard Algorithm Names Specification](https://docs.oracle.com/en/java/javase/17/docs/specs/security/standard-names.html#securerandom-number-generation-algorithms)for information about standard RNG algorithm names.
| | `params` | `SecureRandomParameters`: the`SecureRandomParameters`the newly created`SecureRandom`object must support.
| | `provider` | `Provider`: the provider.
| | Returns || |------------------------------------------------------------------------------------|------------------------------------| | [SecureRandom](https://developer.android.com/reference/java/security/SecureRandom) | the new`SecureRandom`object
| | Throws || |------------------------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------| | [IllegalArgumentException](https://developer.android.com/reference/java/lang/IllegalArgumentException) | if the specified provider or params is`null` | | [NoSuchAlgorithmException](https://developer.android.com/reference/java/security/NoSuchAlgorithmException) | if the specified provider does not support a`SecureRandomSpi`implementation for the specified algorithm and parameters | | [NullPointerException](https://developer.android.com/reference/java/lang/NullPointerException) | if`algorithm`is`null` | **See also:** - [Provider](https://developer.android.com/reference/java/security/Provider) ### getInstanceStrong Added in[API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public static SecureRandom getInstanceStrong () ``` Returns a`SecureRandom`object. In Android this is equivalent to get a SHA1PRNG from AndroidOpenSSL. Some situations require strong random values, such as when creating high-value/long-lived secrets like RSA public/private keys. To help guide applications in selecting a suitable strong`SecureRandom`implementation, Java distributions include a list of known strong`SecureRandom`implementations in the`securerandom.strongAlgorithms`Security property. Every implementation of the Java platform is required to support at least one strong`SecureRandom`implementation.
| Returns || |------------------------------------------------------------------------------------|---------------------------------------------| | [SecureRandom](https://developer.android.com/reference/java/security/SecureRandom) | a strong`SecureRandom`implementation
| | Throws || |------------------------------------------------------------------------------------------------------------|------------------------------| | [NoSuchAlgorithmException](https://developer.android.com/reference/java/security/NoSuchAlgorithmException) | if no algorithm is available | **See also:** - [Security.getProperty(String)](https://developer.android.com/reference/java/security/Security#getProperty(java.lang.String)) ### getParameters Added in[API level 35](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public SecureRandomParameters getParameters () ``` Returns the effective[SecureRandomParameters](https://developer.android.com/reference/java/security/SecureRandomParameters)for this`SecureRandom`instance. The returned value can be different from the`SecureRandomParameters`object passed into a`getInstance`method, but it cannot change during the lifetime of this`SecureRandom`object. A caller can use the returned value to find out what features this`SecureRandom`supports.
| Returns || |--------------------------------------------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | [SecureRandomParameters](https://developer.android.com/reference/java/security/SecureRandomParameters) | the effective[SecureRandomParameters](https://developer.android.com/reference/java/security/SecureRandomParameters)parameters, or`null`if no parameters were used.
| **See also:** - [SecureRandomSpi](https://developer.android.com/reference/java/security/SecureRandomSpi) ### getProvider Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public final Provider getProvider () ``` Returns the provider of this`SecureRandom`object.
| Returns || |----------------------------------------------------------------------------|--------------------------------------------------| | [Provider](https://developer.android.com/reference/java/security/Provider) | the provider of this`SecureRandom`object.
| ### getSeed Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public static byte[] getSeed (int numBytes) ``` Returns the given number of seed bytes, computed using the seed generation algorithm that this class uses to seed itself. This call may be used to seed other random number generators. This method is only included for backwards compatibility. The caller is encouraged to use one of the alternative`getInstance`methods to obtain a`SecureRandom`object, and then call the`generateSeed`method to obtain seed bytes from that object.
| Parameters || |------------|-----------------------------------------------------| | `numBytes` | `int`: the number of seed bytes to generate.
| | Returns || |----------|------------------------| | `byte[]` | the seed bytes.
| | Throws || |--------------------------------------------------------------------------------------------------------|-------------------------| | [IllegalArgumentException](https://developer.android.com/reference/java/lang/IllegalArgumentException) | if`numBytes`is negative | **See also:** - [setSeed(byte)](https://developer.android.com/reference/java/security/SecureRandom#setSeed(byte[])) ### nextBytes Added in[API level 35](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public void nextBytes (byte[] bytes, SecureRandomParameters params) ``` Generates a user-specified number of random bytes with additional parameters.
| Parameters || |----------|------------------------------------------------------------| | `bytes` | `byte`: the array to be filled in with random bytes
| | `params` | `SecureRandomParameters`: additional parameters
| | Throws || |------------------------------------------------------------------------------------------------------------------|--------------------------------------------------------------------------| | [NullPointerException](https://developer.android.com/reference/java/lang/NullPointerException) | if`bytes`is null | | [UnsupportedOperationException](https://developer.android.com/reference/java/lang/UnsupportedOperationException) | if the underlying provider implementation has not overridden this method | | [IllegalArgumentException](https://developer.android.com/reference/java/lang/IllegalArgumentException) | if`params`is`null`, illegal or unsupported by this`SecureRandom` | ### nextBytes Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public void nextBytes (byte[] bytes) ``` Generates a user-specified number of random bytes.
| Parameters || |---------|-------------------------------------------------------------| | `bytes` | `byte`: the array to be filled in with random bytes.
| ### reseed Added in[API level 35](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public void reseed (SecureRandomParameters params) ``` Reseeds this`SecureRandom`with entropy input read from its entropy source with additional parameters. Note that entropy is obtained from an entropy source. While some data in`params`may contain entropy, its main usage is to provide diversity.
| Parameters || |----------|---------------------------------------------------| | `params` | `SecureRandomParameters`: extra parameters
| | Throws || |------------------------------------------------------------------------------------------------------------------|---------------------------------------------------------------------------| | [UnsupportedOperationException](https://developer.android.com/reference/java/lang/UnsupportedOperationException) | if the underlying provider implementation has not overridden this method. | | [IllegalArgumentException](https://developer.android.com/reference/java/lang/IllegalArgumentException) | if`params`is`null`, illegal or unsupported by this`SecureRandom` | ### reseed Added in[API level 35](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public void reseed () ``` Reseeds this`SecureRandom`with entropy input read from its entropy source.
| Throws || |------------------------------------------------------------------------------------------------------------------|---------------------------------------------------------------------------| | [UnsupportedOperationException](https://developer.android.com/reference/java/lang/UnsupportedOperationException) | if the underlying provider implementation has not overridden this method. | ### setSeed Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public void setSeed (long seed) ``` Reseeds this random object, using the eight bytes contained in the given`long seed`. The given seed supplements, rather than replaces, the existing seed. Thus, repeated calls are guaranteed never to reduce randomness. This method is defined for compatibility with`java.util.Random`.
| Parameters || |--------|--------------------------| | `seed` | `long`: the seed.
| **See also:** - [getSeed(int)](https://developer.android.com/reference/java/security/SecureRandom#getSeed(int)) ### setSeed Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public void setSeed (byte[] seed) ``` 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. A PRNG`SecureRandom`will not seed itself automatically if`setSeed`is called before any`nextBytes`or`reseed`calls. The caller should make sure that the`seed`argument contains enough entropy for the security of this`SecureRandom`.
| Parameters || |--------|--------------------------| | `seed` | `byte`: the seed.
| **See also:** - [getSeed(int)](https://developer.android.com/reference/java/security/SecureRandom#getSeed(int)) ### toString Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` public String toString () ``` Returns a Human-readable string representation of this`SecureRandom`.
| Returns || |--------------------------------------------------------------------|----------------------------------| | [String](https://developer.android.com/reference/java/lang/String) | the string representation
| ## Protected methods ### next Added in[API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) ``` protected final int next (int numBits) ``` Generates an integer containing the user-specified number of pseudo-random bits (right justified, with leading zeros). This method overrides a`java.util.Random`method, and serves to provide a source of random bits to all of the methods inherited from that class (for example,`nextInt`,`nextLong`, and`nextFloat`).
| Parameters || |-----------|----------------------------------------------------------------------------------------| | `numBits` | `int`: number of pseudo-random bits to be generated, where`0 <= numBits <= 32`.
| | Returns || |-------|-----------------------------------------------------------------------------------------------------------------| | `int` | an`int`containing the user-specified number of pseudo-random bits (right justified, with leading zeros).
|