Method xor

src/main/java/com/thealgorithms/ciphers/Blowfish.java:1121–1130

This method returns a string obtained by XOR-ing two strings of same length passed a method parameters @param String a and b are string objects which will be XORed and are to be of same length @return String object obtained by XOR operation on String a and String b

(String a, String b)

     * @return String object obtained by XOR operation on String a and String b
     * */
    private String xor(String a, String b) {
        a = hexToBin(a);
        b = hexToBin(b);
        StringBuilder ans = new StringBuilder();
        for (int i = 0; i < a.length(); i++) {
            ans.append((char) (((a.charAt(i) - '0') ^ (b.charAt(i) - '0')) + '0'));
        }
        ans = new StringBuilder(binToHex(ans.toString()));
        return ans.toString();
    }

    /**
     * This method returns addition of two hexadecimal numbers passed as parameters and moded with