Class SecureRandom

dw.crypto

Class SecureRandom

Object

dw.crypto.SecureRandom

The SecureRandom class provides a cryptographically strong random number generator (RNG). See the Internet Engineering Task Force (IETF) RFC 1750: Randomness Recommendations for Security for more information.

Typical callers of SecureRandom invoke the following methods to retrieve random bytes:

      Bytes bytes...
      SecureRandom random = new SecureRandom();
      Bytes nextBytes = random.nextBytes(bytes);

or more convenient to get a Bytes with the demanded length

      int length = 32;
      SecureRandom random = new SecureRandom();
      Bytes nextBytes = random.nextBytes(length);

dw.crypto.SecureRandom is intentionally an adapter for generating cryptographic hard random numbers.

SecureRandom()

Instantiates a new secure random.

generateSeed(numBytes : Number) : Bytes

Returns the given number of seed bytes, computed using the seed generation algorithm that this class uses to seed itself.

nextBytes(numBits : Number) : Bytes

Generates a user-specified number of random bytes.

nextInt() : Number

Returns the next pseudorandom, uniformly distributed int value from this random number generator's sequence.

nextInt(upperBound : Number) : Number

Returns a pseudorandom, uniformly distributed int value between 0 (inclusive) and the specified value (exclusive), drawn from this random number generator's sequence.

nextNumber() : Number

Returns the next pseudorandom, uniformly distributed Number value between 0.0 (inclusive) and 1.0 (exclusive) from this random number generator's sequence.

setSeed(seed : Bytes) : void

Reseeds this random object.

Methods inherited from class Object

assign, create, create, defineProperties, defineProperty, entries, freeze, fromEntries, getOwnPropertyDescriptor, getOwnPropertyNames, getOwnPropertySymbols, getPrototypeOf, hasOwnProperty, is, isExtensible, isFrozen, isPrototypeOf, isSealed, keys, preventExtensions, propertyIsEnumerable, seal, setPrototypeOf, toLocaleString, toString, valueOf, values

SecureRandom

public SecureRandom()

Instantiates a new secure random.

generateSeed

generateSeed(numBytes : Number) : Bytes

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 - the number of seed bytes to generate.

Returns:

the seed bytes.

nextBytes

nextBytes(numBits : Number) : Bytes

Generates a user-specified number of random bytes.

If a call to setSeed had not occurred previously, the first call to this method forces this SecureRandom object to seed itself. This self-seeding will not occur if setSeed was previously called.

Parameters:

numBits - the demanded number of bits

Returns:

a randomly filled Bytes

nextInt

nextInt() : Number

Returns the next pseudorandom, uniformly distributed int value from this random number generator's sequence. The general contract of nextInt is that one int value is pseudorandomly generated and returned. All 2³² possible int values are produced with (approximately) equal probability.

Returns:

the next pseudorandom, uniformly distributed int value from this random number generator's sequence

nextInt

nextInt(upperBound : Number) : Number

Returns a pseudorandom, uniformly distributed int value between 0 (inclusive) and the specified value (exclusive), drawn from this random number generator's sequence.

Parameters:

upperBound - the bound on the random number to be returned. Must be positive.

Returns:

the next pseudorandom, uniformly distributed int value between 0 (inclusive) and upperBound (exclusive) from this random number generator's sequence

Throws:

IllegalArgumentException - if n is not positive

nextNumber

nextNumber() : Number

Returns the next pseudorandom, uniformly distributed Number value between 0.0 (inclusive) and 1.0 (exclusive) from this random number generator's sequence.

Returns:

the next pseudorandom, uniformly distributed Number value between 0.0 and 1.0 from this random number generator's sequence

setSeed

setSeed(seed : Bytes) : void

Reseeds this random object. The given seed supplements, rather than replaces, the existing seed. Thus, repeated calls are guaranteed never to reduce randomness.

Parameters:

seed - the seed.