Go App Shit

So it's been a while since I wrote.. I now have an opportunity to get involved with Apps.. So I'm gonna write as I learn.

Specifically when I talk about App, I'm gonna write about Mobile Apps.

You can definitions on http://en.wikipedia.org/wiki/Mobile_app

A mobile app is a software application running on your phone, tablet etc...

It allows you as a user to perform certain specific tasks. Depends on your requirement, be accounts, entertainment, news you have apps for almost everything these days. 

Some Apps are bundled with devices/handset providers for easy access to users.

There are 3 steps if you're considering making an App:

1. Development

2. Management

3. Distribution

Sonar Cellphones

I’m sure you’ve watched Dark Night and were blown away by the awesome Phone Mr Fox develops which can emit sound pulses.

A sonar image of surrounding area of the phone gets reconstructed by the reflections of these pulses. And you’re like WTF, is this even possible. Well, its not impossible, difficult but not impossible.

You know that submarines use it to detect their surrounding areas and ultrasound machines are used to check on unborn babies. These surroundings however, aren’t cluttered with noise. Move back to Batman, how does he do this in a crowded place? Low frequencies cant see around corners. They cannot bend around obstacles. You need to have a direct and unobstructed path to be able to see something.Just like a sonogram.

 

A cell phone frequency is faced with multiple obstacles and hence a clear picture might not be possible. As frequency increases the wavelength keeps getting thinner. At high frequencies cause severe reductions which limits your cell range terribly.

 

And if you’re an avid cellphone user, you will agree, signaling isn’t real time. And your phone wll never pick up the direction of the wave or even send information in the direction of the wave.

Now Batman, like our Rajnikanth, also arranges for his program code to be installed in every cellphone in Gotham city. This turn every bloody cellphone into a spy detector, which continuously listens to its surrounding areas and transforms them into sonar signals which is ultimately sent to this Giant computer. This computer scans for the Jokers voice just to find his location.

Well this it seems is reality. Apparently after the 9/11 attacks, the US government has installed these tracking software in every cellphone(Yea right!). There are rumors that the NSA’s ECHELON program can pick out voices from millions of calls. Read more onhttp://en.wikipedia.org/wiki/Echelon_(signals_intelligence)

 

Hmmm….i hate the idea of “Someone Somewher is WATCHING”

Sonar Cellphones

I’m sure you’ve watched Dark Night and were blown away by the awesome Phone Mr Fox develops which can emit sound pulses.

A sonar image of surrounding area of the phone gets reconstructed by the reflections of these pulses. And you’re like WTF, is this even possible. Well, its not impossible, difficult but not impossible.

You know that submarines use it to detect their surrounding areas and ultrasound machines are used to check on unborn babies. These surroundings however, aren’t cluttered with noise. Move back to Batman, how does he do this in a crowded place? Low frequencies cant see around corners. They cannot bend around obstacles. You need to have a direct and unobstructed path to be able to see something.Just like a sonogram.

 

A cell phone frequency is faced with multiple obstacles and hence a clear picture might not be possible. As frequency increases the wavelength keeps getting thinner. At high frequencies cause severe reductions which limits your cell range terribly.

 

And if you’re an avid cellphone user, you will agree, signaling isn’t real time. And your phone wll never pick up the direction of the wave or even send information in the direction of the wave.

Now Batman, like our Rajnikanth, also arranges for his program code to be installed in every cellphone in Gotham city. This turn every bloody cellphone into a spy detector, which continuously listens to its surrounding areas and transforms them into sonar signals which is ultimately sent to this Giant computer. This computer scans for the Jokers voice just to find his location.

Well this it seems is reality. Apparently after the 9/11 attacks, the US government has installed these tracking software in every cellphone(Yea right!). There are rumors that the NSA’s ECHELON program can pick out voices from millions of calls. Read more onhttp://en.wikipedia.org/wiki/Echelon_(signals_intelligence)

 

Hmmm….i hate the idea of “Someone Somewher is WATCHING”

Bluejacking

I believe everyone has played at least 1 prank in the entire life not necessarily on April Fools day. If you haven’t, then I’m sure someone has most definitely played a prank on you. The most common prank I can think of are blank calls. Although it might just get you into trouble, if you have a cranky called party its  quite harmless I’d like to think.

 

For the more technically inclined original pranksters – Prank Phone calls = BlueJacking. You would need to have Bluetooth technology though. BlueJacking just takes advantage of the loophole in the messaging system of Bluetooth technology. It allows a user to send unsolicited message to other Bluetooth users in the nearby area.

 

A bluejacker will find his victims in crowded locations, like malls, railway stations, airports, even in his own office. Basically areas with higher potential of Bluetooth users.

 

So how is bluejacking actually done? What is the loophole?

 

 

You might be aware that Bluetooth technology generally operates via low power radio waves @ a frequency of 2 GHZ. This is also known as the ISM band- which is an open, unlicensed band which is actually supposed to be used for industrial, scientific and medical devices( check DOT for more info).

 

So, in the same area multiple Bluetooth devices share the same ISM band and are able to locate and communicate with each other.

 

That’s how you can share music, pictures, text messages etc. Here your device will search for the other device it needs to connect to and tap into its resources. Bluejackers have devised a very simple technique to trick their victims. Instead of creating a legitimate name in the address book, the bluejacker's message takes the place of the name. The prank essentially erases the "from" part of the equation, allowing the Bluejacker to send anything he wishes without indentifying himself.

 

For example imagine yourself at Café Coffee day, you notice a pleasant couple (Bluetooth users)sipping on some hot chocolate. You can set up a contact as “Is your chocolate hot enough?” After choosing to send the SMS via Bluetooth, your mobile will search for Bluetooth devices in its vicinity.

What follows is a mixed expression of confusion and fear much to the Bluejackers delight.

 

IN - Blocking of prepaid subscribers white UAT

I always felt configurations at the IN were as follows while testing your prepaid cards in other networks.

SCP: CAMEL phase and VLR address

SDP: Rates and profile

HLR: CAMEL phase

VLR : CAMEL Phase

The camel phase in all 3 nodes had to be equal or back compatible.

I also felt that there was no way of restricting usage on the VLR. As the VLR wouldn’t be able to identify if the inroamer is prepaid or postpaid and before you have a CAMEL tie-up you need to first have a postpaid( GSM ) launch. In other words, your postpaid customers should be able to roam first. So, if a network is open for postpaid subscribers, it is by default it is open for prepaid guys.

The restriction has to be done at your HLR. So, if they opened a particular VLR, they would allow every prepaid guy to make usage in the network that VLR supports.

Today, I learnt that you can create a separate profile for only those test IMSIs and allow only them to roam on another network.

You might wonder why this concept isn’t used for HNIs and why you need a hub like Roamware to determine preference settings when your HLR can so perfectly restrict usage to a particular network.

The HLR can restrict not determine 1^st and 2^nd preference.

History of GSM

First Networks were MTS (Mobile Telephone Service)

· Pre cellular radio service

· There had to be operator assisted at all times on both sides ie. If you called from a landline, the operator would answer and transfer the call to another operator who would transfer the call to the recipient

· Channels are prone to network congestion & Interference

0G:

· IMTS (Improved Mobile Telephone Service)

· Links PSTNs( Public switched Telephone network) commonly known as Landlines

· No need for an operator

· Used only for voice calls

· Analog Mode

· Most common IMTS phone was the Motorola TLD 1100

· It uses two circuit boards to perform channel scanning and digit decoding

· All logic is performed with transistors

· In a given city, one IMTS base station channel is marked Idle by the transmission of a steady 2000 Hz "idle" tone. Mobiles would scan the available frequencies and lock on to the channel transmitting the idle tone.

· When a call is placed to a mobile, the idle tone would change to 1800 Hz "channel seize" tone, and the 7 digit mobile number (3 digits of area code and 4 digits of subscriber number) would be sent out as rotary dial pulses, switching between 2000 and 1800 Hz to represent digits.

· Any mobile recognizing that the call was for someone else would resume scanning for marked idle tone, while the called mobile would then transmit 2150 Hz "guard" tone back to the base station. This would also initiate ringing at the mobile, and when the mobile subscriber picked up the phone, 1633 Hz "connect" tone would be sent back to the base station to indicate answer supervision and the voice path would be cut through. When the mobile hung up, a burst of alternating 1336 "disconnect" and 1800 Hz "seize" tones would be sent to allow the base station to service another call.

· Mobiles would originate calls by sending a burst of connect tone, to which the base station responded with a burst of seize tone. The mobile would then respond with its identification, consisting of its area code and last four digits of the phone number sent at 20 pulses per second, just as in inward dialing but with the addition of rudimentary parity checking. Digits are formed with a pulsetrain of alternating tones, either connect and silence (for odd digits) or connect and guard (for even digits). When the base station received the calling party's identification, it would send dialtone to the mobile. The user would then use the rotary dial, which would send the dialed digits as an alternating 10 pps pulse train (originally, directly formed by the rotary dial) of connect and guard tones.

1 G:

· AMPS ( Advanced Mobile Phone system)

· Single Frequency was used for a single user

· Similar to 0G but it uses more computing power to select frequencies, hand off to PSTNS, handle billing and Call set-up

Network Jammers & Interceptors

What are Jammers?
So, what is the basic functionality of jammers? Jammers are high frequency transmitters deployed for blocking mobile signals from reaching BTS (for outgoing calls) or mobile phones (for incoming calls).

The jammers can act as a virtual transmitter and interfere with the normal working of cellphones, blocking both incoming and outgoing calls.

Jammers Vs Interceptors

Used mainly by military and law-enforcing agencies, deployment of jammers is considered illegal in most of the countries. The primary goal of jammers is to block cellphones in areas where they are forbidden by law, such as jails and in other places where it creates a nuisance, such as: churches, theatres, concerts halls, or conference halls.

For jails, service providers can opt for either of two solutions-detectors & jammers; and interceptors. In the first case, radio signals are detected by putting detectors in different cells, wherever required, and when the signals are detected it jams the signals.

This helps in jamming a particular area of the jail where prisoner movement takes place rather than jamming the entire jail and affecting the entire communications system. Its cost ranges between RS 200,000 and Rs 14,00,000.

Also, service providers can opt for interceptors that are currently in use by majority of the jails worldwide. Considered to be an intelligent device, the interceptors act as an all in one device and perform functionalities of a sensor, jammer, and recording system.

So, depending upon the conversation, one can either jam or record. The intelligent system costs are on a higher side and it is in the range of Rs 80,00,000.

But before deploying any of the two solutions, the service provider has to do a site survey to test the signal as is done in the case of installation of BTS. Since, jamming range is a function of signal strength received form a nearby base station and varies from one location to another. Even the jamming range varies with respect to different networks in a given location. Jamming also depends on topography of that area, thickness of the wall, reflection/absorption of signals in the given area, area to be covered, and frequencies to be jammed.

Once the survey is done, the service providers are in a better position to design an efficient system by knowing the number and positioning of the jammers. The service providers can either opt for a particular frequency band (GSM/CDMA) or can opt for a mix of VHF/UHF/CDMA/GSM/satellite phone/WI-Fi/Bluetooth/DECT. Care should also be taken to see that in case of power failure there are adequate backup facilities so that the jamming/interception systems can function even without assured power supply.

Once all these factors are taken into account, service providers can ensure that jamming/interception system is foolproof and will also help in preventing highly influential and powerful personalities from misusing mobile phones while being lodged in jail.