Class 0 SMS (flash SMS) on Android

For rooted Android it is possible to bypass an API and send Class 0 SMS. There is a project on Git Hub called ZeroSMS:

ZeroSMS is a proof-of-concept demonstrating a way to send Class 0 SMS on android >=2.3.

Note: this only works on versions 2.2 -> 4.1.2, the sendRawPdu method was removed, so you will need to find a new way to do this.


It was possible to send Flash SMS (that's the term for class 0 SMS) before Android 2.2. Google removed the sendRawPdu API, so even if you used reflection, you wouldn't be able to do it.

Here's how I did it previously (this was tested on Android 1.6 and worked)

private void sendSms(String phone, String sms) {
    if ((phone == null) || (sms == null) || (phone.length() == 0)
            || (sms.length() == 0)) {
        String message = "Phone or message empty!!!";
        Toast notification = Toast.makeText(getBaseContext(), message,
                Toast.LENGTH_SHORT);
        notification.show();
        return;
    }

    // SecurityManager oldSM = System.getSecurityManager();
    // MySecurityManager newSM = new MySecurityManager();
    // System.setSecurityManager(newSM);

    // ServiceManager.getService("isms")
    // ServiceManager.getService("isms");

    SmsManager m = SmsManager.getDefault();
    PendingIntent sentIntent = PendingIntent
            .getBroadcast(this, 0, new Intent(
                    MessageStatusReceiver_MESSAGE_STATUS_RECEIVED_ACTION),
                    0);

    PendingIntent deliveryIntent = PendingIntent.getBroadcast(this, 0,
            new Intent(SmsReceiverService_MESSAGE_SENT_ACTION), 0);

    // String sms = "Message self-destroyed!!!";
    // String phone = "93634096";

    long NOW = System.currentTimeMillis();
    String time = String.valueOf(NOW);

    // // m.sendTextMessage(phone, null, sms, sentIntent, deliveryIntent);
    // working // m.sendTextMessage(phone, null, sms, null, null);
    byte[] bb = new byte[1];
    Method m2 = null;
    try {
        m2 = SmsManager.class.getDeclaredMethod("sendRawPdu",
                bb.getClass(), bb.getClass(), PendingIntent.class,
                PendingIntent.class);
    } catch (SecurityException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (NoSuchMethodException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

    // send message

    SmsMessage.SubmitPdu pdus = SmsMessage.getSubmitPdu(null, phone, sms,
            false);

    // http://android.git.kernel.org/?p=platform/frameworks/base.git;a=blob;f=telephony/java/android/telephony/gsm/SmsMessage.java;h=9ccfa90d2e24e5caea26c1deac641b3c31ae56d4;hb=c883b143ba2b8bfe2f2033d00dee9ff733f1b59c

    boolean submitted = false;
    try {
        byte[] encodedMessage = pdus.encodedMessage;
        // byte[0] = mtiByte
        // byte[1] = TP Message Reference
        // byte[2] = length of source phone
        // byte[3..length] = phone
        // protocol identifier
        int msgLen = encodedMessage[2] / 2;
        // +2 -> length of source phone
        // +2 -> for 91 after the length
        // +1 -> TP PID
        int indexTPDCS = msgLen + 5;
        byte TPDCS = encodedMessage[indexTPDCS];
        // System.out.println(TPDCS);
        System.out.println(getHexString(encodedMessage));
        byte[] changedMessage = encodedMessage.clone();
        // Set bit 4 to 1 using OR (|), indicating there is a message class
        // Set bit 0 and 1 to 0 using AND (&), indicating class 0
        byte newTPDCS = (byte) ((TPDCS | 0x10) & 0xFC); // Flash SMS
        changedMessage[indexTPDCS] = newTPDCS; // Class 0
        System.out.println(getHexString(changedMessage));
        // Log.d(SmsScheduler_TAG, getHexString(changedMessage));
        boolean send = true;
        if (send) {
            m2.invoke(m, pdus.encodedScAddress, changedMessage, null, null);

            // sendSMS(HexDump.bytesToHexString(pdus.encodedScAddress),
            // HexDump.bytesToHexString(changedMessage), null);

            String message = "Flash SMS sent to " + phone
                    + " successfully!";
            Toast notification = Toast.makeText(getBaseContext(), message,
                    Toast.LENGTH_SHORT);
            notification.show();
            Log.d(SmsScheduler_TAG, message);
            submitted = true;
        }
    } catch (IllegalArgumentException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (UnsupportedEncodingException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (IllegalAccessException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (InvocationTargetException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

            // not essential, saves the SMS sent. 
    if (submitted) {
        ContentValues values = new ContentValues();
        values.put(ADDRESS, phone);
        values.put(DATE, time);
        values.put(READ, 0);
        values.put(STATUS, -1);
        values.put(TYPE, MESSAGE_TYPE_SENT);
        values.put(BODY, sms);

        Uri inserted = getContentResolver().insert(
                Uri.parse("content://sms"), values);
    }

    // System.setSecurityManager(oldSM);

}

Scrool's answer is indeed correct, https://stackoverflow.com/a/12873325/3082310 , as ZeroSMS does send flash SMS's; however, it is a Proof-of-Concept and only supports SMS's with 7-bit encoding.

For proper encoding it seems there is a need to modify the code and add if-then or switch-case statements: For 7-bit coding, as in english

use (byte)0xF0

For 16-bit encoding, UCS-2 encoding

use (byte) 0x18

Otherwise, junk characters appear if you enter unsupported language.

Tags:

Android

Sms

Gsm