CRIPTOFONINO
The GSM phone that cannot be intercepted

The technology invents for us more and more powerful devices that overrides the distances and increase the productivity. The system of mobile telephony GSM (Global System for Mobile Communications) represents one of the more significant steps toward the global communication. More than 2 billions of people in all the world, exchange informations (voice, messages, images) with GSM phones that can be reached on international scale, thanks to Roaming contracts. All these informations travels in the air through the "cells" of the radiomobile network and then in the computers of telephony operators, in the form of digital data. But are them safe from intrusive ears and eyes?
 


THE SECURITY OF GSM SYSTEM

The system GSM foresees a cryptography of the conversations, to guarantee the users' privacy.
Cryptography algorithms protect the communication between telephone and BTS (Basic Tranceiver Station, the radio repeater). The communication between BTS and rest of the net is not protected, so it is easily interceptable.
Actually, also between telephone and BTS the security is not ensured. With a special back pack, it is possible to simulate the presence of a radio repeater and decode the conversations sent from the GSM telephone, by exploiting the weakness of the encrypting system. This sort of espionage called man-in-the-middle, is frequently used to grab the industrial secrets.
 

The term "cryptography" derives from greek words kryptós that means hidden and gráphein that means to write. The "hidden writings" are obtained with math functions which change the data of origin in incomprehensible symbols (ciphering). These symbols can be "deciphered" if one knows the "ciphering key". The data processing security is based on numerous ciphering systems called "ciphering algorithms".


HOW THE CRIPTOFONINO WORKS

To get round these security leaks an only system exists: to use a more efficient ciphering algorithm and to do an end-to-end ciphering (that is from phone to phone). The Criptofonino starts from the voice turns it into data (coding) with AES256 ciphering algorithm (the system used by USA government to protect top secret documents). A coding key is used, that is a set of numbers and letters that combines with the data and "signs" them in a univocal way. In receipt data are decrypted with a decoding key and again turned into voice. The process is bidirectional to allow the normal telephone conversation. This way all the data sent to the GSM network are already encrypted and can be only understood by another Criptofonino qualified to receive them. Ciphering keys are password protected and can be modified by the user or produced automatically. It is possible to associate different keys to every user in the phone book of the Criptofonino and Caspertech can neither know the used keys. Ciphering is done in such a way that the same datum ciphered with the same password will result different every time it come encrypted.
 


- The users of a Criptofonino use their SIM CARD, so they must not change number and operator. Only exception if the operator does not support the use of the data channel, indispensable to make sure telephone calls. In this case is always possible using the ciphedred SMS with the same security guarantees.

- The Criptofonino can keep on making normal telephone calls not encrypted, that obviously stay not sure. Who owns a Criptofonino, can use all the GSM networs in international Roaming. So two Criptofonino can make a sure telephone call from a head the other of the world.

- The informations exchanged by the Criptofonino are not interceptable neither at the telephony operators'. However, if the security force consider it necessary, the GSM network manager can disable the not interceptable telephone users.



AUDIO QUALITY AND CALL COSTS

The greater challenge of realtime (that is without high delays) audio ciphering systems is to preserve the quality of the speech. After years of study on the coding systems and thanks to the elaboration power of the modern mobile telephones (true computers in miniature) is now possible to guarantee an audio of excellent quality. The only difference between the "not much sure" conversations and those coded with AES256 is a slight delay in case of congestion of the net. Comparable to international phone calls.
To transmit coded digital audio, is used the data channel of the GSM system, necessary to guarantee support high capacity and constant informations flow. This channel (not to confuse with the GPRS or the WAP) is provided by the standard of telephony, but normally is not used. Generally call costs for the use of the data channel are euqal to the cost of a normal call. So as well as the security, the convenience stays guaranteed.




SOFTWARE & HARDWARE OF THE CRIPTOFONINO

One of the key strengths of the Criptofonino as regards other encrypting telephony solutions is the use of not modified commercial hardware. The software CrypTech, developed on Windows Mobile platform, is installed on normal Smartphones or PDAphones, selected on the basis of their high calculation power. To avoid software copy attempts and guarantee trusted updates, the program is bound to the hardware of the Criptofonino and can only work with a specific device. Updates are encrypted and are only recognized by the corresponding hardware. The all one without intervening on the electronic circuits, so without invalidating the original warranty of the builder.


ENCRYPTED SMS

Text messages (SMS) are more dangerous than the voice, in interception case. SMS are always memorized on the operators' servers as simple text easy to read for whoever has access to the operator's data processing structures. With SMS CRYPTO, the messages ciphering software, the text comes sent on the net in binary format (as the bells or the logos) ciphered. Only the appointed addressee, that owns a Criptofonino, can decode the message after inserting a password. What all that is memorized on the operator's server is an illegible bit sequence. To increase the security, the message is cancelled automatically after reading, without possibility of memorizing on the telephone or exporting it. A written communication that auto destroys without leaving traces and without giving up the advantages of SMS.


PICTURES AND DOCUMENTS ENCRYPTING

The Criptofonino other than ciphering the voice communications can code any file (photography, doc, note, etc.) and give the possibility of moving the data or preserving them in a sure way in shelter from thefts or loss of the device. For istance is possible to send mail from the phone by inserting ciphered attachments.
Documents will be decoded by another Criptofonino or also on PC, with a flash drive USB CRYPTECH. This kind of data is also ciphered with the AES256 algorithm (the same used for the telephone calls) with the same security level.



THE COMPANY Caspertech
Born in Turin, in the technological area of Politecnico called I3P (http://www.i3p.it), Caspertech is engaged in the sector of the security with a team of researchers bring up to date constantly on the new tools for the protection of the informations. The activities of Caspertech go from the design of anti interception devices to the satellite and cellular tracing, to the access control with biometric devices. A growing number of international customers and high level of flexibility to supplement the solutions of corporate security, makes Caspertech a well-established reference for the privacy safeguard.


CONCLUSIONS

In communications privacy protection is a must, this is Caspertech slogan. In a world where everything travels in electronic form is important to protect informations before entrusting them to the digital highways. The Criptofonino works in this sense and offers a practical, versatile, user friendly solution. In the following some useful links.

Caspertech Homepage:
http://www.Caspertech.com/

Informations request:
http://www.Caspertech.com/informazioni.php

Description of the Criptofonino:
http://www.Caspertech.com/prodotti.php

GSM World Association:
http://www.gsmworld.com/
 
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