http://www.bouncycastle.org/java.html: The Bouncy Castle Crypto package is a Java implementation of cryptographic algorithms. This jar contains JCE provider and lightweight API for the Bouncy Castle Cryptography APIs for JDK 1.5 to JDK 1.8.
  • The Legion of the Bouncy Castle Inc. 
package org.bouncycastle.crypto;

import java.security.SecureRandom;


The base class for symmetric, or secret, cipher key generators.

/**
 * The base class for symmetric, or secret, cipher key generators.
 */
public class CipherKeyGenerator
{
    protected SecureRandom  random;
    protected int           strength;

    
initialise the key generator.

Params:
  • param – the parameters to be used for key generation
/**
     * initialise the key generator.
     *
     * @param param the parameters to be used for key generation
     */
    public void init(
        KeyGenerationParameters param)
    {
        this.random = param.getRandom();
        this.strength = (param.getStrength() + 7) / 8;
    }

    
generate a secret key.

Returns:a byte array containing the key value.
/**
     * generate a secret key.
     *
     * @return a byte array containing the key value.
     */
    public byte[] generateKey()
    {
        byte[]  key = new byte[strength];

        random.nextBytes(key);

        return key;
    }
}