encrypt & decrypt randomly strings

SimpleStringEncryption.java

class SimpleStringEncryption {
  
  public static String encrypt(String str){
    int code;
    String result = "";
    for (int i = 0; i < str.length(); i++) {
      code = Math.round((float) Math.random()*8+1);
      result += code + Integer.toHexString( ((int) str.charAt(i) ) ^ code )+"-";
    }
    return result.substring(0, result.lastIndexOf("-"));
  }

  public static String decrypt(String str){
    str = str.replace("-", "");
    String result = "";
    for (int i = 0; i < str.length(); i+=3) {
      String hex =  str.substring(i+1, i+3);
      result += (char) (Integer.parseInt(hex, 16) ^ (Integer.parseInt(String.valueOf(str.charAt(i)))));
    }
    return result;
  }
  
	public static void main (String[] args) {
		String e = "some text to encrypt";
		String encrypted = encrypt(e);
		System.out.println(encrypted);
		System.out.println(decrypt(encrypted));
	}  
  
}