/*******************************************************************************
 *******************************************************************************/
package at.gv.egiz.eaaf.core.impl.idp.process.support;

import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;

/**
 * Holder for a secure random instance following the initialization on demand holder design pattern. The secure random
 * instance is a singleton that is initialized on first usage.
 * 
 * @author tknall
 * 
 */
public class SecureRandomHolder {

	private SecureRandomHolder() {
	}

	private static final SecureRandom SRND_INSTANCE;
	static {
		try {
			SRND_INSTANCE = SecureRandom.getInstance("SHA1PRNG");
		} catch (NoSuchAlgorithmException e) {
			throw new RuntimeException("Unable to instantiate SHA1PRNG.", e);
		}
	}

	/**
	 * Returns a secure random generator instance.
	 * @return The secure random instance.
	 */
	public static SecureRandom getInstance() {
		return SecureRandomHolder.SRND_INSTANCE;
	}

}