// Scanner object for user input

Scanner keyboard = new Scanner(System.in);

// Constants and array variables

final int DELTA_ONE = 0x11111111;

final int DELTA_TWO = 0x22222222;

int[] K = new int[4];

int[] L = new int[3];

int[] R = new int[3];

public static void main(String[] args) {

TEA_Encryption Tea = new TEA_Encryption();

// Call method to get user keys

Tea.getKeys();

// Call method to get user plaintext

Tea.getPlaintext();

// Call method to initialize L[] and R[]

Tea.initializeLR();

// Call method to encrypt the plaintext in L[0] and R[0]

Tea.encrypt();

System.out.println();

// Call method to print the output

Tea.printCiphertext();

}

// Get keys from user

public void getKeys() {

for(int i = 0; i < K.length; i++) {

System.out.print("Please input K[" + i + "] in Hex String (without '0x'): ");

String key = keyboard.nextLine();

K[i] = Integer.parseUnsignedInt(key, 0, key.length(), 16);

System.out.println();

}

}

// Get plaintext from user

public void getPlaintext() {

// Getting L[0]

System.out.print("Please input L[0] in Hex String (without '0x'): ");

String L0 = keyboard.nextLine();

L[0] = Integer.parseUnsignedInt(L0, 0, L0.length(), 16);

System.out.println();

// Getting R[0]

System.out.print("Please input R[0] in Hex String (without '0x'): ");

String R0 = keyboard.nextLine();

R[0] = Integer.parseUnsignedInt(R0, 0, R0.length(), 16);

}

// Initialize L[] and R[]

public void initializeLR() {

// Initializing L[1], L[2], R[1], and R[2] as 0x00000000

for(int i = 1; i < L.length; i++) {

L[i] = R[i] = 0x00000000;

}

}

// TEA algorithm for encryption

public void encrypt() {

for(int i = 1; i < 2; i++) {

// i will only be 1, using it for index

L[i] = R[i-1];

R[i] = (L[i-1] + (((R[i-1] << 4) + K[i-1]) ^ ((R[i-1] >>> 5) + K[i]) ^ (R[i-1] + DELTA_ONE)));

L[i+1] = R[i];

R[i+1] = (L[i] + (((R[i] << 4) + K[i+1]) ^ ((R[i] >>> 5) + K[i+2]) ^ (R[i] + DELTA_TWO)));

}

}

// Print method for ciphertext

public void printCiphertext() {

// for loop to run through all L[] and R[] values

for(int i = 0; i < L.length; i++) {

// Format Hex Strings

String leftHex = String.format("%1$08X", L[i]);

String rightHex = String.format("%1$08X", R[i]);

// Print output

System.out.print("L[" + i + "] = " + leftHex + "\t\t");

System.out.println("R[" + i + "] = " + rightHex);

}

}

}