import java.security.AlgorithmParameters;
import java.security.SecureRandom;
import java.security.spec.KeySpec;
import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.PBEKeySpec;
import javax.crypto.spec.SecretKeySpec;
class SecurityUtils {
private static final byte[] salt = { (byte) 0xA4, (byte) 0x0B, (byte) 0xC8,
(byte) 0x34, (byte) 0xD6, (byte) 0x95, (byte) 0xF3, (byte) 0x13 };
private static int BLOCKS = 128;
public static byte[] encryptAES(String seed, String cleartext)
throws Exception {
byte[] rawKey = getRawKey(seed.getBytes("UTF8"));
SecretKeySpec skeySpec = new SecretKeySpec(rawKey, "AES");
Cipher cipher = Cipher.getInstance("AES");
cipher.init(Cipher.ENCRYPT_MODE, skeySpec);
return cipher.doFinal(cleartext.getBytes("UTF8"));
}
public static byte[] decryptAES(String seed, byte[] data) throws Exception {
byte[] rawKey = getRawKey(seed.getBytes("UTF8"));
SecretKeySpec skeySpec = new SecretKeySpec(rawKey, "AES");
Cipher cipher = Cipher.getInstance("AES");
cipher.init(Cipher.DECRYPT_MODE, skeySpec);
return cipher.doFinal(data);
}
private static byte[] getRawKey(byte[] seed) throws Exception {
KeyGenerator kgen = KeyGenerator.getInstance("AES");
SecureRandom sr = SecureRandom.getInstance("SHA1PRNG");
sr.setSeed(seed);
kgen.init(BLOCKS, sr); // 192 and 256 bits may not be available
SecretKey skey = kgen.generateKey();
byte[] raw = skey.getEncoded();
return raw;
}
private static byte[] pad(byte[] seed) {
byte[] nseed = new byte[BLOCKS / 8];
for (int i = 0; i < BLOCKS / 8; i++)
nseed[i] = 0;
for (int i = 0; i < seed.length; i++)
nseed[i] = seed[i];
return nseed;
}
public static byte[] encryptPBE(String password, String cleartext)
throws Exception {
SecretKeyFactory factory = SecretKeyFactory
.getInstance("PBKDF2WithHmacSHA1");
KeySpec spec = new PBEKeySpec(password.toCharArray(), salt, 1024, 256);
SecretKey tmp = factory.generateSecret(spec);
SecretKey secret = new SecretKeySpec(tmp.getEncoded(), "AES");
Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
cipher.init(Cipher.ENCRYPT_MODE, secret);
AlgorithmParameters params = cipher.getParameters();
byte[] iv = params.getParameterSpec(IvParameterSpec.class).getIV();
return cipher.doFinal(cleartext.getBytes("UTF-8"));
}
public static String decryptPBE(SecretKey secret, String ciphertext,
byte[] iv) throws Exception {
Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
cipher.init(Cipher.DECRYPT_MODE, secret, new IvParameterSpec(iv));
return new String(cipher.doFinal(ciphertext.getBytes()), "UTF-8");
}
}