Java Language Generate Cryptographically Random Data


Example

To generate samples of cryptographically random data:

final byte[] sample = new byte[16];

new SecureRandom().nextBytes(sample);

System.out.println("Sample: " + DatatypeConverter.printHexBinary(sample));

Produces output similar to:

Sample: E4F14CEA2384F70B706B53A6DF8C5EFE

Note that the call to nextBytes() may block while entropy is gathered depending on the algorithm being used.

To specify the algorithm and provider:

final byte[] sample = new byte[16];
final SecureRandom randomness = SecureRandom.getInstance("SHA1PRNG", "SUN");

randomness.nextBytes(sample);

System.out.println("Provider: " + randomness.getProvider());
System.out.println("Algorithm: " + randomness.getAlgorithm());
System.out.println("Sample: " + DatatypeConverter.printHexBinary(sample));

Produces output similar to:

Provider: SUN version 1.8
Algorithm: SHA1PRNG
Sample: C80C44BAEB352FD29FBBE20489E4C0B9