Moved classic code to classic branch

src/main/java/org/openautonomousconnection/dns/utils/Utils.java

@@ -0,0 +1,65 @@
+/*
+ * Copyright (C) 2024 Open Autonomous Connection - All Rights Reserved
+ *
+ * You are unauthorized to remove this copyright.
+ * You have to give Credits to the Author in your project and link this GitHub site: https://github.com/Open-Autonomous-Connection
+ * See LICENSE-File if exists
+ */
+
+package org.openautonomousconnection.dns.utils;
+
+import java.nio.charset.StandardCharsets;
+import java.security.MessageDigest;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+public class Utils {
+    public static String createAccessKey(String input) {
+        return sha256(shuffleString(sha256(input) + getAlphaNumericString(5) +
+                sha256(getAlphaNumericString(5)) +
+                sha256(getAlphaNumericString(5)) +
+                sha256(getAlphaNumericString(5))));
+    }
+
+    public static String sha256(final String base) {
+        try {
+            final MessageDigest digest = MessageDigest.getInstance("SHA-256");
+            final byte[] hash = digest.digest(base.getBytes(StandardCharsets.UTF_8));
+            final StringBuilder hexString = new StringBuilder();
+
+            for (byte b : hash) {
+                final String hex = Integer.toHexString(0xff & b);
+                if (hex.length() == 1) hexString.append('0');
+                hexString.append(hex);
+            }
+
+            return hexString.toString();
+        } catch (Exception ex) {
+            throw new RuntimeException(ex);
+        }
+    }
+
+    public static String getAlphaNumericString(int length) {
+        String chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789abcdefghijklmnopqrstuvxyz";
+        StringBuilder builder = new StringBuilder(length);
+
+        for (int i = 0; i < length; i++) {
+            int index = (int) (chars.length() * Math.random());
+            builder.append(chars.charAt(index));
+        }
+
+        return builder.toString();
+    }
+
+    public static String shuffleString(String input) {
+        List<Character> characters = new ArrayList<>();
+        for (char c : input.toCharArray()) characters.add(c);
+
+        Collections.shuffle(characters);
+        StringBuilder shuffledString = new StringBuilder();
+
+        for (char c : characters) shuffledString.append(c);
+        return shuffledString.toString();
+    }
+}