com.github.davidcarboni.cryptolite

Class Random

java.lang.Object

com.github.davidcarboni.cryptolite.Random

public class Random
extends Object

This class provides random functions, such as Salt, ID and password generation. It also allows you to get a singleton SecureRandom instance.

Author:

David Carboni

Field Summary

Fields

Modifier and Type	Field and Description
static String	ALGORITHM The algorithm for the SecureRandom instance: "SHA1PRNG".
static int	ID_BITS The length of IDs: 256.
static int	SALT_BYTES The length of salt values: 16.

Constructor Summary

Constructors

Constructor and Description
Random()

Method Summary

Methods

Modifier and Type	Method and Description
static byte[]	bytes(int length) Convenience method to instantiate and populate a byte array of the specified length.
static SecureRandom	getInstance()
static String	id()
static InputStream	inputStream(long length) Convenience method to instantiate an InputStream of random data of the specified length.
static String	password(int length) Convenience method to generate a random password.
static String	salt() Generates a random salt value.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

ID_BITS

public static final int ID_BITS

The length of IDs: 256.

See Also:

Constant Field Values

ALGORITHM

public static final String ALGORITHM

The algorithm for the SecureRandom instance: "SHA1PRNG".

See Also:

Constant Field Values

SALT_BYTES

public static final int SALT_BYTES

The length of salt values: 16.

See Also:

Constant Field Values

Constructor Detail

Random

public Random()

Method Detail

getInstance

public static SecureRandom getInstance()

Returns:

A lazily-instantiated, cached SecureRandom instance for the algorithm "SHA1PRNG". This is a global instance and is thread-safe. The only consideration is whether thread contention could be an issue. See http://stackoverflow.com/questions /1461568/is-securerandom-thread-safe for more details.

bytes

public static byte[] bytes(int length)

Convenience method to instantiate and populate a byte array of the specified length.

Parameters:

length - The length of the array.

Returns:

SecureRandom.nextBytes(byte[])

inputStream

public static InputStream inputStream(long length)

Convenience method to instantiate an InputStream of random data of the specified length.

Parameters:

length - The length of the stream.

Returns:

SecureRandom.nextBytes(byte[])

id

public static String id()

Returns:

A 256-bit (32 byte) random ID as a hexadecimal string.

password

public static String password(int length)

Convenience method to generate a random password. This method no longer uses Apache RandomStringUtils.random(int, int, int, boolean, boolean, char[], java.util.Random) , because the implementation of that method calls Random.nextInt(), which is not overridden by the SecureRandom returned by getInstance(). That means passwords wouldn't be generated using cryptographically strong pseudo random numbers, despite passing a SecureRandom.

Parameters:

length - The length of the password to be returned.

Returns:

A String of the specified length, composed of uppercase letters, lowercase letters and numbers.

salt

public static String salt()

Generates a random salt value. If a salt value is needed by an API call, the JavaDoc of that method should reference this method. Other than than, it should not be necessary to call this in normal usage of this library.

Returns:

A 16-byte random salt value as a base64-encoded string (for easy storage).