VernumCipherCode

package monoalphabeticcipher;

/**
 *
 * @author Md Ali Shaikh
 */
public class VernamCipher {
    public static String ALPHABET = "abcdefghijklmnopqrstuvwxyz";

    public String getCipheredText(String plainText, String oneTimePad){
        plainText = plainText.toLowerCase();
        oneTimePad = oneTimePad.toLowerCase();
        String cipheredText = "";
        boolean doExit = false;
        
        if(plainText.length() == oneTimePad.length()){
            String[] pTArr = plainText.split(" ");
            String[] oTPArr = oneTimePad.split(" ");
            
            if(pTArr.length == oTPArr.length){
                for (int i = 0; i < pTArr.length; i++) {
                    if(pTArr[i].length() == oTPArr[i].length()){
                    String plainTextWord = pTArr[i], oneTimePadWord = oTPArr[i];
                    int len = plainTextWord.length();
                        for (int j = 0; j < len; j++) {
                            String ptChar = String.valueOf(plainTextWord.charAt(j));
                            String otpChar = String.valueOf(oneTimePadWord.charAt(j));
                            int ptPos = ALPHABET.indexOf(ptChar);
                            int otpPos = ALPHABET.indexOf(otpChar);
                            int initial = ptPos + otpPos;
                            if(initial>25){
                                initial = initial - 26; 
                            }
                            
                            cipheredText += ALPHABET.charAt(initial);
                        }
                        cipheredText += " ";
                    }else{
                        doExit = true;
                        break;
                    }
                }
   
            }
            else{
                doExit = true;
            }
        }else{
            doExit = true;
        }
        if (doExit) {
            System.out.println("The sequence for the plain text and OTP is not equal..");
            System.exit(0);
        }
        return cipheredText;
    }

    public static void main(String[] args) {
        VernamCipher vc = new VernamCipher();
        String plainText = "i am fine thanku";
        String oneTimePad = "x mp ypgn hnlpqr";
        //System.out.println(plainText + " + " + oneTimePad );
        System.out.println("plainText: "+plainText);
        System.out.println("oneTimePad: "+oneTimePad);
        String cipheredText = vc.getCipheredText(plainText, oneTimePad);
        System.out.println("cipheredText: "+cipheredText);
    }
}