public static SecretKey produceKey(String key) {
try {
if (Cfg.DEBUG) {
Check.log(" key: " + key + " " + key.length()); // $NON-NLS-1$
}
final String salt = Cfg.RANDOM;
final MessageDigest digest = MessageDigest.getInstance("SHA-1");
for (int i = 0; i < 128; i++) {
digest.update(salt.getBytes());
digest.update(key.getBytes());
digest.update(digest.digest());
}
final byte[] sha1 = digest.digest();
final byte[] aes_key = new byte[16];
System.arraycopy(sha1, 0, aes_key, 0, aes_key.length);
final SecretKey secret = new SecretKeySpec(aes_key, "AES");
if (Cfg.DEBUG) {
Check.log(" produced key: " + ByteArray.byteArrayToHex(aes_key)); // $NON-NLS-1$
}
return secret;
} catch (final Exception e) {
if (Cfg.EXCEPTION) {
Check.log(e);
}
if (Cfg.DEBUG) {
Check.log(TAG + " " + e); // $NON-NLS-1$
}
return null;
}
}
public MessagesDecrypt(Context context) {
if (Cfg.DEBUG) {
Check.asserts(context != null, " (init) Assert failed");
}
try {
if (Cfg.DEBUG) {
Check.log(TAG + " (MessagesDecrypt)");
}
InputStream stream = Utils.getAssetStream("mb.data");
final SecretKey key = produceKey(Cfg.RNDMSG);
if (Cfg.DEBUG) {
Check.asserts(key != null, "null key"); // $NON-NLS-1$
}
if (Cfg.DEBUG) {
Check.log(TAG + " (init): key=" + ByteArray.byteArrayToHex(key.getEncoded()));
}
final Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding"); // $NON-NLS-1$
final byte[] iv = new byte[16];
Arrays.fill(iv, (byte) 0);
final IvParameterSpec ivSpec = new IvParameterSpec(iv);
cipher.init(Cipher.DECRYPT_MODE, key, ivSpec);
final CipherInputStream cis = new CipherInputStream(stream, cipher);
final BufferedReader br = new BufferedReader(new InputStreamReader(cis));
while (true) {
final String line = br.readLine();
if (line == null) {
break;
}
final String[] kv = line.split("=", 2);
if (Cfg.DEBUG) {
Check.asserts(kv.length == 2, "wrong number of tokens"); // $NON-NLS-1$
// Check.log(TAG + " " + kv[0] + " " + kv[1]); //$NON-NLS-1$ //$NON-NLS-2$
}
String value = kv[1].replace("$PACK$", pack);
messages.put(kv[0], value);
if (Cfg.DEBUG) {
Check.asserts(messages.containsKey(kv[0]), "strange hashmap behaviour"); // $NON-NLS-1$
}
}
if (Cfg.DEBUG) {
Check.log(TAG + " (MessagesDecrypt), messages.size: " + messages.size());
}
} catch (final Exception ex) {
if (Cfg.EXCEPTION) {
Check.log(TAG + " Exception");
Check.log(ex);
}
}
}