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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
}
}
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