import java.util.*;

public class KeySchedule {

// Circular left shift by 1 bit

public static String shiftIt(String input) {

return input.substring(1) + input.charAt(0);

}

// for encryption:

public static Queue<String> generateKeys(String inputKey) {

Queue<String> keys = new LinkedList<>();

String binaryKey = Main.toBinary(inputKey).substring(0, 56); // force exactly 56 bits

String C = binaryKey.substring(0, 28);

String D = binaryKey.substring(28);

// generate for loop for 10 subkeys:

for (int i = 0; i < 10; i++) {

C = shiftIt(C);

D = shiftIt(D);

String combined = C + D; // 56 bits

String subkey = combined.substring(0, 32); // first 32 bits

keys.add(subkey);

}

return keys;

}

// for decryption:

public static Stack<String> generateKeysReverse(String inputKey) {

Stack<String> reversed = new Stack<>();

List<String> forward = new ArrayList<>(generateKeys(inputKey));

for (int i = forward.size() - 1; i >= 0; i--) {

reversed.push(forward.get(i));

}

return reversed;

}

}