private String decryptServicesDotXml() throws Exception {
byte[] encryptedData = null;
String decryptedString = null;
// retrieve the key
long timestamp = System.currentTimeMillis();
timestamp -= timestamp % timestampMod;
URL url =
new URL(
String.format(
"http://services.appmobi.com/external/clientservices.aspx?feed=OA&appname=%s×tamp=%d",
activity.configData.appName, timestamp));
InputStream in = url.openConnection().getInputStream();
ByteArrayOutputStream keyStream = new ByteArrayOutputStream();
FileUtils.copyInputStream(in, keyStream);
in.close();
byte[] keyBytes = new byte[24], keyStreamBytes = keyStream.toByteArray();
String keyMark = "key=\"";
System.arraycopy(
keyStreamBytes,
(new String(keyStreamBytes).indexOf(keyMark) + keyMark.length()),
keyBytes,
0,
keyBytes.length);
keyStream.close();
// read the encrypted data from file into byte[]
File servicesDotXml = new File(activity.baseDir(), "services.xml");
InputStream is = new FileInputStream(servicesDotXml);
long length = servicesDotXml.length();
encryptedData = new byte[(int) length];
int offset = 0, numRead = 0;
while (offset < encryptedData.length
&& (numRead = is.read(encryptedData, offset, encryptedData.length - offset)) >= 0) {
offset += numRead;
}
is.close();
// set up crypto objects
final SecretKey key = new SecretKeySpec(keyBytes, "DESede");
final Cipher decipher = Cipher.getInstance("DESede/ECB/NoPadding");
decipher.init(Cipher.DECRYPT_MODE, key);
// decrypt data and return string
final byte[] plainText = decipher.doFinal(encryptedData);
decryptedString = new String(plainText, "UTF-8");
return decryptedString;
}
