randomizing masterkeys is now a explicit task, so random numbers are not needed when loading a masterkey file from disk. trying to use an uninitialized cryptor results in runtime exceptions

main/crypto-api/src/main/java/org/cryptomator/crypto/AbstractCryptorDecorator.java

@@ -22,6 +22,11 @@ public class AbstractCryptorDecorator implements Cryptor {
 		this.cryptor = cryptor;
 	}
 
+	@Override
+	public void randomizeMasterKey() {
+		cryptor.randomizeMasterKey();
+	}
+
 	@Override
 	public void encryptMasterKey(OutputStream out, CharSequence password) throws IOException {
 		cryptor.encryptMasterKey(out, password);

main/crypto-api/src/main/java/org/cryptomator/crypto/Cryptor.java

@@ -27,6 +27,11 @@ import org.cryptomator.crypto.exceptions.WrongPasswordException;
  */
 public interface Cryptor extends Destroyable {
 
+	/**
+	 * Assigns new random bytes to the keys in this Cryptor instance.
+	 */
+	void randomizeMasterKey();
+
 	/**
 	 * Encrypts the current masterKey with the given password and writes the result to the given output stream.
 	 */