public class

SecureRandom

extends Random

java.lang.Object
↳	java.util.Random
	↳	java.security.SecureRandom

Class Overview

SecureRandom is an engine class which is capable of generating cryptographically secure pseudo-random numbers.

Summary

Public Constructors
	SecureRandom() Constructs a new instance of `SecureRandom`.
	SecureRandom(byte[] seed) Constructs a new instance of `SecureRandom`.

Protected Constructors
	SecureRandom(SecureRandomSpi secureRandomSpi, Provider provider) Constructs a new instance of `SecureRandom` using the given implementation from the specified provider.

Public Methods
byte[]	generateSeed(int numBytes) Generates and returns the specified number of seed bytes, computed using the seed generation algorithm used by this `SecureRandom`.
String	getAlgorithm() Returns the name of the algorithm of this `SecureRandom`.
static SecureRandom	getInstance(String algorithm, String provider) Returns a new instance of `SecureRandom` that utilizes the specified algorithm from the specified provider.
static SecureRandom	getInstance(String algorithm, Provider provider) Returns a new instance of `SecureRandom` that utilizes the specified algorithm from the specified provider.
static SecureRandom	getInstance(String algorithm) Returns a new instance of `SecureRandom` that utilizes the specified algorithm.
final Provider	getProvider() Returns the provider associated with this `SecureRandom`.
static byte[]	getSeed(int numBytes) Generates and returns the specified number of seed bytes, computed using the seed generation algorithm used by this `SecureRandom`.
synchronized void	nextBytes(byte[] bytes) Generates and stores random bytes in the given `byte[]` for each array element.
synchronized void	setSeed(byte[] seed) Reseeds this `SecureRandom` instance with the specified `seed`.
void	setSeed(long seed) Reseeds this this `SecureRandom` instance with the eight bytes described by the representation of the given `long seed`.

Protected Methods
final int	next(int numBits) Generates and returns an `int` containing the specified number of random bits (right justified, with leading zeros).

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Inherited Methods

From class java.util.Random

synchronized int	next(int bits) Returns a pseudo-random uniformly distributed `int` value of the number of bits specified by the argument `bits` as described by Donald E.
boolean	nextBoolean() Returns the next pseudo-random, uniformly distributed `boolean` value generated by this generator.
void	nextBytes(byte[] buf) Modifies the `byte` array by a random sequence of `byte`s generated by this random number generator.
double	nextDouble() Generates a normally distributed random `double` number between 0.0 inclusively and 1.0 exclusively.
float	nextFloat() Generates a normally distributed random `float` number between 0.0 inclusively and 1.0 exclusively.
synchronized double	nextGaussian() Pseudo-randomly generates (approximately) a normally distributed `double` value with mean 0.0 and a standard deviation value of `1.0` using the polar method of G.
int	nextInt(int n) Returns a new pseudo-random `int` value which is uniformly distributed between 0 (inclusively) and the value of `n` (exclusively).
int	nextInt() Generates a uniformly distributed 32-bit `int` value from the random number sequence.
long	nextLong() Generates a uniformly distributed 64-bit integer value from the random number sequence.
synchronized void	setSeed(long seed) Modifies the seed a using linear congruential formula presented in The Art of Computer Programming, Volume 2, Section 3.2.1.

From class java.lang.Object

Object	clone() Creates and returns a copy of this `Object`.
boolean	equals(Object o) Compares this instance with the specified object and indicates if they are equal.
void	finalize() Is called before the object's memory is being reclaimed by the VM.
final Class<? extends Object>	getClass() Returns the unique instance of `Class` which represents this object's class.
int	hashCode() Returns an integer hash code for this object.
final void	notify() Causes a thread which is waiting on this object's monitor (by means of calling one of the `wait()` methods) to be woken up.
final void	notifyAll() Causes all threads which are waiting on this object's monitor (by means of calling one of the `wait()` methods) to be woken up.
String	toString() Returns a string containing a concise, human-readable description of this object.
final void	wait(long millis, int nanos) Causes the calling thread to wait until another thread calls the `notify()` or `notifyAll()` method of this object or until the specified timeout expires.
final void	wait(long millis) Causes the calling thread to wait until another thread calls the `notify()` or `notifyAll()` method of this object or until the specified timeout expires.
final void	wait() Causes the calling thread to wait until another thread calls the `notify()` or `notifyAll()` method of this object.

Public Constructors

public SecureRandom ()

Since: API Level 1

Constructs a new instance of SecureRandom. An implementation for the highest-priority provider is returned. The constructed instance will not have been seeded.

public SecureRandom (byte[] seed)

Since: API Level 1

Constructs a new instance of SecureRandom. An implementation for the highest-priority provider is returned. The constructed instance will be seeded with the parameter.

Parameters

seed	the seed for this generator.

Protected Constructors

protected SecureRandom (SecureRandomSpi secureRandomSpi, Provider provider)

Since: API Level 1

Constructs a new instance of SecureRandom using the given implementation from the specified provider.

Parameters

secureRandomSpi	the implementation.
provider	the security provider.

Public Methods

public byte[] generateSeed (int numBytes)

Since: API Level 1

Generates and returns the specified number of seed bytes, computed using the seed generation algorithm used by this SecureRandom.

Parameters

numBytes	the number of seed bytes.

Returns

the seed bytes.

public String getAlgorithm ()

Since: API Level 1

Returns the name of the algorithm of this SecureRandom.

Returns

the name of the algorithm of this SecureRandom.

public static SecureRandom getInstance (String algorithm, String provider)

Since: API Level 1

Returns a new instance of SecureRandom that utilizes the specified algorithm from the specified provider.

Parameters

algorithm	the name of the algorithm to use.
provider	the name of the provider.

Returns

a new instance of SecureRandom that utilizes the specified algorithm from the specified provider.

Throws

NoSuchAlgorithmException	if the specified algorithm is not available.
NoSuchProviderException	if the specified provider is not available.
NullPointerException	if `algorithm` is `null`.

public static SecureRandom getInstance (String algorithm, Provider provider)

Since: API Level 1

Returns a new instance of SecureRandom that utilizes the specified algorithm from the specified provider.

Parameters

algorithm	the name of the algorithm to use.
provider	the security provider.

Returns

a new instance of SecureRandom that utilizes the specified algorithm from the specified provider.

Throws

NoSuchAlgorithmException	if the specified algorithm is not available.
NullPointerException	if `algorithm` is `null`.

public static SecureRandom getInstance (String algorithm)

Since: API Level 1

Returns a new instance of SecureRandom that utilizes the specified algorithm.

Parameters

algorithm	the name of the algorithm to use.

Returns

a new instance of SecureRandom that utilizes the specified algorithm.

Throws

NoSuchAlgorithmException	if the specified algorithm is not available.
NullPointerException	if `algorithm` is `null`.

public final Provider getProvider ()

Since: API Level 1

Returns the provider associated with this SecureRandom.

Returns

the provider associated with this SecureRandom.

public static byte[] getSeed (int numBytes)

Since: API Level 1

Generates and returns the specified number of seed bytes, computed using the seed generation algorithm used by this SecureRandom.

Parameters

numBytes	the number of seed bytes.

Returns

the seed bytes

public synchronized void nextBytes (byte[] bytes)

Since: API Level 1

Generates and stores random bytes in the given byte[] for each array element.

Parameters

bytes	the `byte[]` to be filled with random bytes.

public synchronized void setSeed (byte[] seed)

Since: API Level 1

Reseeds this SecureRandom instance with the specified seed. The seed of this SecureRandom instance is supplemented, not replaced.

Parameters

seed	the new seed.

public void setSeed (long seed)

Since: API Level 1

Reseeds this this SecureRandom instance with the eight bytes described by the representation of the given long seed. The seed of this SecureRandom instance is supplemented, not replaced.

Parameters

seed	the new seed.

Protected Methods

protected final int next (int numBits)

Since: API Level 1

Generates and returns an int containing the specified number of random bits (right justified, with leading zeros).

Parameters

numBits	number of bits to be generated. An input value should be in the range [0, 32].

Returns

an int containing the specified number of random bits.

Interfaces

Classes

Enums

Exceptions

SecureRandom

Class Overview

Summary

Public Constructors

public SecureRandom ()

public SecureRandom (byte[] seed)

Parameters

Protected Constructors

protected SecureRandom (SecureRandomSpi secureRandomSpi, Provider provider)

Parameters

Public Methods

public byte[] generateSeed (int numBytes)

Parameters

Returns

public String getAlgorithm ()

Returns

public static SecureRandom getInstance (String algorithm, String provider)

Parameters

Returns

Throws

public static SecureRandom getInstance (String algorithm, Provider provider)

Parameters

Returns

Throws

public static SecureRandom getInstance (String algorithm)

Parameters

Returns

Throws

public final Provider getProvider ()

Returns

public static byte[] getSeed (int numBytes)

Parameters

Returns

public synchronized void nextBytes (byte[] bytes)

Parameters

public synchronized void setSeed (byte[] seed)

Parameters

public void setSeed (long seed)

Parameters

Protected Methods

protected final int next (int numBits)

Parameters

Returns