Caesar cipher

CaesarCipher.java

import java.util.Arrays;
import java.util.Objects;

public final class CaesarCipher {

    /**
     * Creates a new instance with specified shift.
     *
     * @param shift the shift
     */
    public CaesarCipher(final int shift) {
	super();
	this.shift = shift;
    }

    public byte[] encrypt(final byte[] decrypted) {
	Objects.requireNonNull(decrypted);
	final byte[] encrypted = new byte[decrypted.length];
	for (int i = 0; i < encrypted.length; i++) {
	    encrypted[i] = (byte) (decrypted[i] + shift);
	}
	return encrypted;
    }

    public byte[] decrypt(final byte[] encrypted) {
	Objects.requireNonNull(encrypted);
	final byte[] decrypted = new byte[encrypted.length];
	for (int i = 0; i < decrypted.length; i++) {
	    decrypted[i] = (byte) (encrypted[i] - shift);
	}
	return decrypted;
    }
    
    private final int shift;
}