Tech

The Crypto Phone

Caspertech presents its latest encrypted GSM mobile phone CRYPTECH technology for the protection of all voice and SMS communications. Available on new attractive phones, our technology benefits from a new audio engine that ensures complete absence of echo and provides the best voice quality, comparable to that of a traditional phone call. Security is assured by the best public encryption algorithm, ASE256, with symmetric 256 bit keys.

Mobile phones encrypted safe Cryptech do not require knowledge or complicated settings. Encryption keys are easy to configure directly by the user, thus ensuring total privacy. The AES algorithm 256, with the use of symmetric keys, ensures the best protection against any kind of interception or eavesdropping for those who use the Criptofonino.

The crypto phone Cryptech, top level product derived from military and government requirements, provides two ways of generating the anti spy encryption key that is used during the conversation: the Diffie-Hellman protocol 4096 bit(or Elliptic Curves Diffie Hellman, according to user preference) provides a session key which is combined with the symmetric key set by the user on the device, producing a different encryption key for each call. Users can employ different combinations of Diffie-Hellman and shared keys thus protecting the phone against any interceptions on the network.

For example, the Diffie-Hellman key can be used without prior sharing of a common key, thus enabling phone calls between encrypted cellphones which do not share common encryption keys. When Diffie-Hellman is employed (both alone and in combination with symmetric shared user keys), the final key will be automatically deleted at the end of the call. User keys can be stored in a secure repository, which is protected by a password. Such keys are displayed on the screen in hash format to ensure secrecy in case of theft of the device or the possibility of comparing two keys on different devices for compatibility.

The simplified version of the secure GSM phone Cryptech called Easy Cryptech offers the same level of security as the enhanced version but it has fewer options, so as to bring encrypted phone calls to the masses. Being a sort of “plug-and-play” anti spy ciphered mobile phone, Easy Cryptech can be employed by inexperienced users because there is no need to configure user keys or mess with advanced settings. A quick key exchange algorithm (ECDH, Elliptic Curves Diffie-Hellman) is employed to automatically generate the cipher key without user intervention on the crypto phone, this cipher key is destroyed at the end of the call. . The strong AES256 algorithm is employed for voice and SMS encryption, offering the best security level in a user-friendly application.

The secret of Cryptech anti spy technology is its simplicity but at the same time it is very powerful. After an automatic initial protocol phase which performs key agreement and synchronization, the encrypted phone turns voice into data, encrypts it and splits it into small packets. Such data packets get transmitted in real-time through the GSM data channel reaching the other device. Upon receiving the secure packets, the other device performs data decryption, assembles the original audio and plays it on the usual phone speaker of the device. In turn, each crypto phone device performs audio encryption and decryption in real time, so as to let the user experience a full-duplex encrypted voice communication, comparable to a normal phone call conversation.

Crypto SMS text messages

SMS messages are encrypted with AES 256 algorithm as well, with cipher keys chosen by users or automatically generated during a secure GSM voice call. Long encrypted anti spy SMS text messages are supported, enabling users to write ciphered SMS messages containing thousand of characters. A recently added function is the clear SMS text secure storage: users can choose to receive traditional SMS message and store them in an encrypted secure archive on the Cryptech or Easy Cryptech secure phone.

Recently, a remote command function has been added to the Cryptech and Easy Cryptech software. Users are given the possibility to execute remote instructions on their secure mobile phones, such as wiping or cellphone GPS localization, only from allowed phone number and by means of a secure secret password. The true potential of the whole system is that all the remote control messages are encrypted SMS text messages, impossible to decode and shielded against phone tapping or eavesdropping. In case of phone theft or lost, the owner can remotely wipe the whole content of the crypto phone and storage card, as well as locate the mobile. Coordinates can be shown on a map on the screen of another Cryptech or Easy Cryptech device which has been formerly allowed by the owner of the lost or stolen phone. Remote mobile GPS location requires GPS compatible devices.

2G vs. 3G

Cryptech 2G and 3G technologyTransmission channels depend on the type of product: 2G or 3G. The following table outlines the transmission protocol and the related delay for both versions. Transmission Delay Cryptech 2G CSD v32 and v110 0,8 sec Cryptech 3G GPRS 3 sec Cryptech 3G EDGE 1.5 sec Cryptech 3G UMTS 0.5-1 sec Cryptech 3G WIFI 0.5-1 sec Latency depends approximatively on· audio coding (1%)· encryption/decryption routines (1%)· serialization and queuing (20%)· network processing (78%)Cryptech 2G 2G technology means that Cryptech for establishing the secure connection uses a CSD data connection with a maximum of 9.6 Kbps of throughput channel.Circuit Switched Data (CSD) is the original form of data transmission developed for the time division multiple access (TDMA)-based mobile phone systems like Global System for Mobile Communications (GSM). CSD uses a single radio time slot to deliver 9.6 kbit/s data transmission to the GSM Network and Switching Subsystem where it could be connected through the equivalent of a normal modem to the Public Switched Telephone Network (PSTN) allowing direct calls to any dial-up service.

In order for Cryptech 2G to work properly, the SIM card operator should activate the CSD data channel for sending and receiving data calls (Mobile Originated/Mobile Terminated). Some operators limit such service to just postpay/business contracts while refusing activation requests which involve prepay cards. When enabling CSD data channel, the operator usually assigns two additional numbers to the SIM card: the first number is reserved for voice calls (and it’s the one the SIM card gets issued with), the second number is reserved for data transmission, the third for faxes. Even if three numbers have been assigned to the SIM card being employed for encrypted calls, usually the main number can be used for all purposes (voice and crypto).Cryptech 2G uses the modem of the phone to establish the communication by means of the standard protocol v32 or v110; those two operation mode differ in handshake duration and information transmitted at the beginning of the connection. With v32 protocol, almost 20 additional seconds are required for the voice channel to get open, moreover some operators require that the call gets directly routed to the data number assigned to the SIM card. The v32 protocol is rather old and used only in few countries in the world.On the other hand, with the v110 protocol (the same used in ISDN modems for Internet browsing) the connection is almost immediate. It usually doesn’t require to dial the data number, it is enough to dial the voice number of the SIM and the data call get automatically routed to the SIM.Cryptech 2G enables the user to set two additional modem settings: Transparent and Non Transparent.

Those settings refer to the transport layer of the modem. Non transparent involves a data flow control and a retransmission of the data that arrive with wrong timing or corrupted. This retransmission causes an increase of the delay of the communication but less audio gaps during the communication. Transparent is usually preferred because in real time communication such as voice conversations it is a better choice that of having low delay and eventually lose some fractions of seconds when data are corrupted rather than hearing empty gaps lasting seconds.Standard default settings of Cryptech 2G is v110 and Transparent and this is the optimal setting for most European operators. Cryptech 2G can be used all over the word but some operators (mainly in Africa or South/Central America) do not implement the CSD data service in their networks because it is normally not used by normal customers and it is – from their low level point of view, not customer’s – more expensive than GPRS/EDGE connection because they have to reserve a full timeslot on the network as if it was a voice call instead of using a best effort politic like in GPRS/EDGE that usually have high delay.1.3 Cryptech 3G3G technology involves the use of all kind of internet connection available to the phone. With the UMTS technology it is possible to take advantage of the broadband capabilities of new networks and having a voice encoding quality higher than 2G while keeping the delay as low as possible. Using an internet connection involves the use of a sever that acts as a switch between the users.

The call is no more routed by operator between voice and data number, it is no more necessary to ask for any service activation/number but only the normal internet connection is needed. The encrypted voice connections between users are made possible through the use of Cryptech Server that blindly routes the encrypted data without any elaboration or manipulation. The communication is always encrypted end-to-end straight from user to user. Caspertech has developed a proprietary VoIP protocol not compatible with SIP or any other industry standard because of the need of a fast, light, secure and efficient protocol designed to be used in mobility and in NATted networks. With this approach, the communication is not easily identified so it can bypass filters in networks that do not allow SIP connections.Cryptech 3G can indifferently use mobile network like UMTS or WIFI, in this way it is possible to use freely the connectivity available in office/home/airport/public hotspot . The communication can start with WIFI and pass automatically to the mobile network as soon as the user is out of the WIFI range without interrupting the conversation.

The protocol was designed for mobility so the codec adapts dynamically the voice coding quality to the bandwidth available. This means tnat on GPRS/EDGE connections, the quality will be a little lower but still sufficient to have good clearness. The delay and the jitter varies dynamically depending on the performances of the network for having the best tradeoff between delay and quality. Best performances are available under UMTS or WIFI coverage so 3G technology is recommended to customers that uses the Cryptech devices mainly in big cities (with good UMTS coverage) or in office/home or for international/intercontinental connections because of better performances/quality/usability/cost efficiency.Cryptech 3G important feature is the complete anonymity of the connection between users because endpoints cannot be traced from the bill of the operator. What can be gathered from the operator receipt or detailed phone bill is simply the connection to an internet server. One additional benefit is that customers – with the aid of technical aids – can test the strength of the encrypted stream and check that is really secure without the need for special instruments for the interception of the stream.

Cryptech 2G

2G technology means that Cryptech for establishing the secure connection uses a CSD data connection with a maximum of 9.6 Kbps of throughput channel.

Circuit Switched Data (CSD) is the original form of data transmission developed for the time division multiple access (TDMA)-based mobile phone systems like Global System for Mobile Communications (GSM). CSD uses a single radio time slot to deliver 9.6 kbit/s data transmission to the GSM Network and Switching Subsystem where it could be connected through the equivalent of a normal modem to the Public Switched Telephone Network (PSTN) allowing direct calls to any dial-up service.

Cryptech 2G uses the modem of the phone to establish the communication by means of the standard protocol v32 or v110; those two operation mode differ in handshake duration and information transmitted at the beginning of the connection. With v32 protocol, almost 20 additional seconds are required for the voice channel to get open, moreover some operators require that the call gets directly routed to the data number assigned to the SIM card. The v32 protocol is rather old and used only in few countries in the world.

On the other hand, with the v110 protocol (the same used in ISDN modems for Internet browsing) the connection is almost immediate. It usually doesn’t require to dial the data number, it is enough to dial the voice number of the SIM and the data call get automatically routed to the SIM.

Cryptech 2G enables the user to set two additional modem settings: Transparent and Non Transparent. Those settings refer to the transport layer of the modem. Non transparent involves a data flow control and a retransmission of the data that arrive with wrong timing or corrupted. This retransmission causes an increase of the delay of the communication but less audio gaps during the communication. Transparent is usually preferred because in real time communication such as voice conversations it is a better choice that of having low delay and eventually lose some fractions of seconds when data are corrupted rather than hearing empty gaps lasting seconds.

Standard default settings of Cryptech 2G is v110 and Transparent and this is the optimal setting for most European operators.

Cryptech 2G can be used all over the word but some operators (mainly in Africa or South/Central America) do not implement the CSD data service in their networks because it is normally not used by normal customers and it is – from their low level point of view, not customer’s – more expensive than GPRS/EDGE connection because they have to reserve a full timeslot on the network as if it was a voice call instead of using a best effort politic like in GPRS/EDGE that usually have high delay.

Cryptech 3G

3G technology involves the use of all kind of internet connection available to the phone. With the UMTS technology it is possible to take advantage of the broadband capabilities of new networks and having a voice encoding quality higher than 2G while keeping the delay as low as possible.

Using an internet connection involves the use of a sever that acts as a switch between the users. The call is no more routed by operator between voice and data number, it is no more necessary to ask for any service activation/number but only the normal internet connection is needed. The encrypted voice connections between users are made possible through the use of Cryptech Server that blindly routes the encrypted data without any elaboration or manipulation. The communication is always encrypted end-to-end straight from user to user. Caspertech has developed a proprietary VoIP protocol not compatible with SIP or any other industry standard because of the need of a fast, light, secure and efficient protocol designed to be used in mobility and in NATted networks. With this approach, the communication is not easily identified so it can bypass filters in networks that do not allow SIP connections.

Cryptech 3G can indifferently use mobile network like UMTS or WIFI, in this way it is possible to use freely the connectivity available in office/home/airport/public hotspot . The communication can start with WIFI and pass automatically to the mobile network as soon as the user is out of the WIFI range without interrupting the conversation. The protocol was designed for mobility so the codec adapts dynamically the voice coding quality to the bandwidth available. This means tnat on GPRS/EDGE connections, the quality will be a little lower but still sufficient to have good clearness. The delay and the jitter varies dynamically depending on the performances of the network for having the best tradeoff between delay and quality. Best performances are available under UMTS or WIFI coverage so 3G technology is recommended to customers that uses the Cryptech devices mainly in big cities (with good UMTS coverage) or in office/home or for international/intercontinental connections because of better performances/quality/usability/cost efficiency.

Cryptech 3G important feature is the complete anonymity of the connection between users because endpoints cannot be traced from the bill of the operator. What can be gathered from the operator receipt or detailed phone bill is simply the connection to an internet server. One additional benefit is that customers – with the aid of technical aids – can test the strength of the encrypted stream and check that is really secure without the need for special instruments for the interception of the stream.

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