sistem sandi caesar dengan JAVA

new caesar().setVisible(true);
}
public String encryptbin(String terang) {
String up = terang.toUpperCase().trim();
char[] chr = new char[up.length()];
for (int i = 0; i < up.length(); i++) {
char temp = (char) (up.charAt(i) + 3);
if(temp > 90) {
chr[i] = (char) ((temp % 90) + 64);
} else {
chr[i] = temp;
}
System.out.println("char: "+(int) chr[i]);
}
return new String(chr);

}
public String decryptbin(String cipher) {
String up = cipher.toUpperCase().trim();
char[] chr = new char[up.length()];
for (int i = 0; i < up.length(); i++) {
char temp = (char) (up.charAt(i) - 3);
if(temp > 90) {
chr[i] = (char) ((temp % 90) + 64);
} else {
chr[i] = temp;
}
System.out.println("char: "+(int) chr[i]);
}
return new String(chr);

}
}