java.security · java.base · since Java 1.1

SecureRandom

declaration

public class SecureRandom extends Random

Cryptographically strong randomness sourced from OS entropy: tokens, salts, IVs, keys. Slower than Random — and the only acceptable choice for security.

Key methods

`static SecureRandom getInstanceStrong()`	The strongest configured algorithm.
`void nextBytes(byte[] bytes)`	Fill with entropy — the salt/IV workhorse.