1 files changed, 110 insertions, 0 deletions
diff --git a/src/main/java/de/thedevstack/conversationsplus/utils/SimpleCryptoUtil.java b/src/main/java/de/thedevstack/conversationsplus/utils/SimpleCryptoUtil.java
new file mode 100644
index 00000000..0a8c80d1
--- /dev/null
+++ b/src/main/java/de/thedevstack/conversationsplus/utils/SimpleCryptoUtil.java
@@ -0,0 +1,110 @@
+package de.thedevstack.conversationsplus.utils;
+
+
+import java.security.InvalidKeyException;
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
+
+import javax.crypto.BadPaddingException;
+import javax.crypto.Cipher;
+import javax.crypto.IllegalBlockSizeException;
+import javax.crypto.NoSuchPaddingException;
+import javax.crypto.SecretKey;
+import javax.crypto.spec.SecretKeySpec;
+
+/**
+ *
+ */
+public final class SimpleCryptoUtil {
+
+    public static String encrypt(String seed, String cleartext) {
+        String result = null;
+        if (null != seed && null != cleartext) {
+            try {
+                byte[] rawKey = getRawKey(seed.getBytes());
+                byte[] encryptedBytes = encrypt(rawKey, cleartext.getBytes());
+                result = toHex(encryptedBytes);
+            } catch (NoSuchAlgorithmException | InvalidKeyException | IllegalBlockSizeException | BadPaddingException | NoSuchPaddingException e) {
+                // FIXME
+            }
+        }
+
+        return result;
+    }
+
+    public static String decrypt(String seed, String encrypted) {
+        String result = null;
+        if (null != seed && null != encrypted) {
+            try {
+                byte[] rawKey = getRawKey(seed.getBytes());
+                byte[] enc = toByte(encrypted);
+                byte[] decryptedBytes = decrypt(rawKey, enc);
+                result = new String(decryptedBytes);
+            } catch (NoSuchAlgorithmException | InvalidKeyException | IllegalBlockSizeException | BadPaddingException | NoSuchPaddingException e) {
+                // FIXME
+            }
+        }
+
+        return result;
+    }
+
+    private static byte[] encrypt(byte[] raw, byte[] clear) throws IllegalBlockSizeException, BadPaddingException, InvalidKeyException, NoSuchAlgorithmException, NoSuchPaddingException {
+        byte[] encrypted = doCipherOperation(raw, clear, Cipher.ENCRYPT_MODE);
+        return encrypted;
+    }
+
+    private static byte[] decrypt(byte[] raw, byte[] encrypted) throws NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException, IllegalBlockSizeException, BadPaddingException {
+        byte[] decrypted = doCipherOperation(raw, encrypted, Cipher.DECRYPT_MODE);
+        return decrypted;
+    }
+
+    private static byte[] doCipherOperation(byte[] raw, byte[] input, int mode) throws NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException, IllegalBlockSizeException, BadPaddingException {
+        SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");
+        Cipher cipher = Cipher.getInstance("AES");
+        cipher.init(mode, skeySpec);
+
+        return cipher.doFinal(input);
+    }
+
+    private static byte[] getRawKey(byte[] seed) throws NoSuchAlgorithmException {
+        MessageDigest md = MessageDigest.getInstance("MD5");
+        byte[] md5Bytes = md.digest(seed); // 128 Bit = 16 byte
+        SecretKey skey = new SecretKeySpec(md5Bytes, "AES");
+        byte[] raw = skey.getEncoded();
+        return raw;
+    }
+
+    public static byte[] toByte(String hexString) {
+        int len = hexString.length() / 2;
+        byte[] result = new byte[len];
+        for (int i = 0; i < len; i++) {
+            result[i] = Integer.valueOf(hexString.substring(2 * i, 2 * i + 2), 16).byteValue();
+        }
+        return result;
+    }
+
+    public static String toHex(byte[] buf) {
+        if (buf == null) {
+            return null;
+        }
+        StringBuffer result = new StringBuffer(2 * buf.length);
+        for (int i = 0; i < buf.length; i++) {
+            appendHex(result, buf[i]);
+        }
+        return result.toString();
+    }
+
+    private final static String HEX = "0123456789ABCDEF";
+
+    private static void appendHex(StringBuffer sb, byte b) {
+        sb.append(HEX.charAt((b >> 4) & 0x0f)).append(HEX.charAt(b & 0x0f));
+    }
+
+    /**
+     * private constructor to avoid instantiation
+     */
+    private SimpleCryptoUtil() {
+        // private constructor to avoid instantiation
+    }
+}
+