WO2012022992A2

WO2012022992A2 - Encryption system for protecting phone calls

Info

Publication number: WO2012022992A2
Application number: PCT/HU2011/000084
Authority: WO
Inventors: Zoltán KOVÁCS
Original assignee: Kovacs Zoltan
Priority date: 2010-08-16
Filing date: 2011-08-12
Publication date: 2012-02-23
Also published as: WO2012022992A3

Abstract

The subject of the invention is encryption system for protecting phone calls, which serves to encrypt telephone calls, primarily for encryption of mobile telephone calls. The system according to the invention uses the telephone network between the calling and called party, primarily mobile telephone network during the identification of the encryption, said system has data communication option, primarily mobile Internet service, beside realizing telephone conversations. The system according to the invention is characterized by that, during the operation of the system the user's telephone number is used in three ways, - the first is the number itself to call from, or to be called, - the second, the telephone number itself is used as an user's ID, functioning not only as a number, but also as an user's identifier, - the third is to issue digital certificates for the users, where the telephone number is used as an identifier, and this way during the call the certificates of the conversing partners are checked, the telephone number is compared with the caller's number, as well as during the operation of the system a datacall is initiated simultaneously with the initiation of the call, which is checked with digital certificates, during which the password is generated by the users themselves, and said password is not recorded anywhere else, and the certificate is issued by the operator of the system, furthermore during the operation of the system the identifiers are handled with such cryptographic methods, that cannot be counterfeited.

Description

Encryption system for protecting ph

The subject of the invention is encryption system for protecting phone calls, which serves to encrypt telephone calls, primarily for encryption of mobile telephone calls.

There is a demand during phone calls that no third party apart from the caller and the person called could learn about the content of the phone call, no one could intercept it. With the improvement of telephone technology the methods of tapping improved as well, therefore various solutions were developed to encrypt telephone conversations.

In connection with the encryption of phone calls one of the most important problems is the problem of identification, verification. It means, that often it is not possible to know for certain, if that person is there who should be there. To eliminate this problem a known solution is a method, when the partners on the two sides quote a series of numbers or key series, from which they can identify themselves. This method in itself did not obviously mean the encryption of the line as well, but it was suitable to make sure, that the suitable parties got into touch on the two sides.

In case of another known solution they wanted to use mobile Internet where the existing phones should be installed. The relative programs had to be installed as well. This solution improved the voice quality, but did not solve the issue of identification.

According to the state of the art the CN 101635924 patent publication discloses a CDMA port-to-port encryption communication system and a key distribution method thereof, the CDMA port-to-port encryption communication system comprises a CDMA network and a terminal mobile telephone thereof, a public switched telephone network and a terminal fixed-line telephone thereof, a short message service center as well as the following three cipher processing units including a cipher chip of a mobile telephone terminal, a key distribution management center (KDMC) and a Firmware cipher module of a gateway mobile switching center. The key distribution management center is used for key distribution management of the communication system. The key distribution is realized by a layered distribution method, i.e. a first layer is an equipment key which is distributed in the process of initialization; a second layer is a key-encryption key and a short message service key which are distributed in startup of an enciphered mobile telephone; and a third layer is a session key which is distributed every time a session is launched between the enciphered mobile telephones. At the same time, by adopting a bidirectional certification technology for key distribution and combination of a key update and remote destroying method, the safety risk in key exposure is reduced, and the communication safety is improved. The EP 2088738 patent publication discloses an end-to-end encrypted communication over mobile network. Transceivers for transmitting and/or receiving cipher data to/from other tranceivers in end-to-end encrypted communication over a mobile network, and methods for transmitting and receiving in such communication. The mobile network is of a type supporting real-time multimedia communication, such as video telephony, with transparency of multimedia data being communicated. Preferably the mobile network is a cellular UMTS network. Cipher data is being sent/received through a circuit switched multimedia bearer service of the mobile network, the bearer service being reserved in the mobile network for multimedia communication. Preferably the multimedia bearer service is UMTS service BS30 transparent for Multimedia.

The EP 2180679 patent publication discloses a secure communications system comprising a detachable security module and a stationary communications unit. The detachable security module comprises encryption means, and is connectable to the stationary unit for receiving encrypted data and delivering decrypted data, and/or receiving clear data and delivering encrypted data. In addition, the detachable security module is a mobile standalone encryption/decryption communications unit provided with its own user interface and access point interface for use as a secure mobile communications unit when disconnected from the stationary unit. A mobile encryption/decryption communications unit and a stationary unit for use in such a secure communications system are also disclosed, as well as a clipon unit for use with the mobile unit.

The FR 2901084 patent publication discolses a method involves ensuring the protection of identity of a client device user by encrypting a certificate with symmetric algorithm handshook by cipherspecs parameter. An encryption key is derived from less weightage bits of a key that is generated from premaster secret and two random values, where a size of the encryption key is determined based on selected symmetric encryption algorithm. An independent claim is also included for a server device for implementing a user identity protection method.

The US 2003079124 patent publication makes known methods, systems, computer data signals, recordable media and methods of doing business for wireless or wired network communication between network resources each having a unique telephone number associated therewith, including, among other feature, forming a primary number file (PNF) comprising a uniform telephone address (UTA) which has a telephone number associated with a network resource. Issuing a temporary Digital Certificates containing UTA for use in at least one Temporary Target (TT), the TT serving as a temporary Target or Mover in the network, wherein a CA Switch issues UTA and UTA DC; transfers the UTA and DC directly to Temporary Target Number File or to a reseller; and the reseller assigns the UTA/DC to a particular temporary Target Primary Number File. Performing session encryption, wherein Targets use shorter key pairs in order to accelerate encryption of on-line audio and video streams; and each Target issuing new pair of shorter public and private keys, storing the private key in an internal memory of the Target, the private key being used only for one session, encrypting a new shorter public key with a sending target original private key, or with a receiving target original public key, and transmitting the encrypted message to the receiving target; and receiving target decrypting the received message containing the new shorter Public Key of the sending target and uses the received sending target public key to encrypt/decrypt the session exchange with sending target.

The WO 0108377 patent publication makes known a system and method for enabling secure connections for voip calls of providing secure signaling connections and media connections for packet data network telephony calls. A secure registration request message containing an encryption technique and public key is sent from an originating gateway oyer a packet data network to a terminating gateway. The terminating gateway returns a secure confirmation message containing a digital certificate over the packet data network to the originating gateway. Once registered, further communication between the gateways is encrypted over the packet data network using the public key and encryption technique specified in the secure registration request message.; The gateways can be linked to other incompatible networks such as the PSTN or wireless telephony networks in order to provide telephone capability among POTS, wireless, and IP phones.

The WO 2007102422 patent publication makes known a sender confirming system, sender confirming method and sender confirming program, wherein a receiver confirms a sender without using a sender's telephone. A sender confirming system is comprised of a transmitter for an outgoing call, a receiver for receiving the outgoing call, and an encryption key distribution server connected to communicate with the transmitter. The encryption key distribution server has an encryption key distribution means for distributing a public key of the receiver. The transmitter is comprised of a certificate encryption means for encrypting a sender certificate, a certificate sending means for sending the sender certificate, and a signing means for encrypting and signing a challenge. The receiver is provided with a decoding means for decoding the sender certificate, a challenge generating means for generating the challenge, a signature verifying means for verifying a signature, and a certificate display means for displaying the sender certificate. Because of transmitting the sender certificate stored in the transmitter and the signature using the encryption key of the transmitter to the receiver, the sender can be confirmed by the receiver.

The WO 2008018947 patent publication makes known a security system for handheld wireless devices using time-variable encryption keys. In one embodiment, the invention provides a portable wireless personal communication system for cooperating with a remote certification authority to employ time variable secure key information pursuant to a predetermined encryption algorithm to facilitate convenient, secure encrypted communication. The disclosed system includes a wireless handset, such as PDA, smartphone, cellular telephone or the like, characterized by a relatively robust data processing capability and a body mounted key generating component which is adapted to be mounted on an individual's body, in a permanent or semi-permanent manner, for wirelessly broadcasting, within the immediate proximity of the individual, a secret or private key identifying signal corresponding to a time variable secure key information under the control of the certification authority.; The key identifying signal is generated in a format that facilitates secure wireless communication with the individual in accordance with a predetermined encryption algorithm including a PKI encryption algorithm. The disclosed system may be used with a console for coordinating access to a variety of different communication system and networks.

The drawbacks of the known solutions are:

Regarding the solutions known so far, it was not certain, where the phone call came from, and it was not possible either to confirm if it was bugged, that is whether the fact, the there is a„man in the middle" none of the parties can notice, existed. They could not confirm either who it was encrypted by. The problem was, that human speech was not comprehensible enough, the voice quality was bad, and they did not include identification. In this area the most up-to-date technique is five to ten years old.

When working out the solution according to the invention we aimed at elaborating a system, that ensures the encryption of telephone calls, primarily mobile phone calls, by automatic identification, at the same time ensures good voice quality of talks and makes possible for the user to use the phone in the usual way.

When working out the solution according to the invention we realized, that in case the telephone number used during the telephone calls are used in several ways, then the set aim can be achieved. The first use takes place in such a way, that the telephone number is the number itself, that should be called to reach the called party. As a second use, the telephone number is used as an user ID, working not only as a number, but as an user^'s identifier as well. Digital certificates are issued on this basis for the users, where the telephone number is used as an identifier, so during the call the certificate of the talking parties is controlled and compared with the telephone number they called from. It takes place in such a way, that at initiating the call, a data call is initiated as well, which is checked by the digital certificates. The password is generated for this by the user themselves, it is not registered anywhere else, the certificate is issued by the operator of the system. The identifiers are handled with a criptographical method, so they can not be falsified.

The invention is an encryption system for protecting phone calls, serving for the enciyption of telephone calls, primarily for encryption of mobile telephone calls, said system uses the telephone network between the calling and called party, primarily mobile telephone network during the identification of the encryption, said system has data communication option, primarily mobile Internet service, beside realizing telephone conversations. The system is characterized by that, during the operation of the system the user^'s telephone number is used in three ways,

- the first is the number itself to call from, or to be called,

- the second, the telephone number itself is used as an user's ID, functioning not only as a number, but also as an user s identifier, - the third is to issue digital certificates for the users, where the telephone number is used as an identifier^ and this way during the call the certificates of the conversing partners are checked, the telephone number is compared with the caller^'s number, as well as during the operation of the system a datacall is initiated simultaneously with the initiation of the call, which is checked with digital certificates, during which the password is generated by the users themselves, and said password is not recorded anywhere else, and the certificate is issued by the operator of the system,

furthermore during the operation of the system the identifiers are handled with such cryptographic methods, that cannot be counterfeited.

In one prefered application of the system according to the invention during the operation of the system the course of the processing of the incoming orders takes place in the steps described below,

the system handles the caller's telephone number, respectively IMEI code as an incoming piece of information, triggering a decision, whether the telephone number is already known, or not,

in case it is not known, then the system handles the caller as a new subscription, in case it is about a new subscription, the registering of the user and password generation take place, as well as the user's registration on the media server, following this, the issuing of the new certificate takes place, and sending advise to the user, in case the decision is Yes, namely the caller's telephone number, respectively IMEI code are known for the system, an additional decision-making situation occurs regarding the moving of the licence,

in case the decision is Yes, then a new IMEI code is registered and the old one is cancelled. Following this the issuing of the new certificate and advising of the user take place,

in case the decision is No, then the subscription is renewed, new password is generated, followed by the issuing of a new certificate and advising the user.

In another prefered application of the system according to the invention during the operation of the system the procedure of initiating a call takes place as described below, the initiation can take place in two ways, one of them is the writing in of the telephone number, the other one is looking it up in the telephone directory and sending it with the call button,

after initiating the call, the system controls if a secure call was initiated,

if Not, then the system handles it as the initiation of a traditional call, which is not handled furthermore encoded,

in case Yes, then the normalization of the telephone number takes place, and the logging in with the telephone number, during which the caller is checked in the central database, and it is decided if a secure call is possible,

if Yes, then the call is initiated,

if No, then the system generates an error message saying, that the party called has no subscription, or is not able to receive a call.

In a further prefered application of the system according to the invention during the operation of the system the building up of a call takes place as described below, during which first the initiating of the call takes place from the part of the calling party, then following this the reconciliation of the encrypting passwords and sending of the caller^'s certificate to the party called,

the receipt of the caller^'s certificate takes place on the side of the party called, then a decision is made, during which it is decided whether the caller's certificate is valid, in case the caller's certificate is not valid, then the call is cut off,

in case the caller^'s certificate is valid, then the forwarding of the certificate of the party called takes place to the calling party,

the receipt of the certificate of the party called takes place at the calling party, as well a decision is made whether the certificate of the party called is valid,

in case the answer is No, then the call is broken,

if the answer is Yes, then the exchange of the encrypting codes take place at both sides, and following this comes the display of the number of the called party, then the system initiates ringing at the caller's side, respectively the device starts ringing at the side called,

at the side called the party decides to receive the call or not,

if Not, then the call is refused,

if Yes, then conversation starts following this.

In a further prefered application of the system according to the invention during the operation of the system the course of registration of the client's side and the central side takes place as described below,

during which first the receipt of the password at the client's side takes place, then following the menu instruction „open new folder", then choosing of the „mobile encryption" follows, and giving the own telephone number and password follows, at the central side finding Ca follows, then giving of the own phone number and password, at the client^'s side password is generated, resulting in the issuing of the certificate at the central side, the certificate is checked at the client's side, then the certificate is fixed, then the telephone number and password are fixed, resulting in the logging in at the central side with phone number and password, resulting in the display„ready to use" message at the client^'s side.

In a further prefered application of the system according to the invention during the operation of the system there is a center, where one must be registered at a central user's registration, in order to realize the call, but the parties are in connection with each other, the data packages are encrypted with digital certificates.

In a further prefered application of the system according to the invention during the operation of the system the users must identify each other both toward the center and toward each other, on basis of the security certificate issued by the center, which means, that if there is no certificate, then logging in is not possible, and if the caller is not identified, the center does not allow logging in, furthermore without a certificate the parties can not get into direct connection with each other either.

In a further prefered application of the system according to the invention during the operation of the system the certificate is a dataseries of abt. 1 KByte length, which is given to the caller at the very first logging in by the center, furthermore a symmetrical password is generated at initiating every call, which is sent to the conversing partner coded with the certificate, then it is confirmed, and the conversation starts with this password.

In a further prefered application of the system according to the invention during the operation of the system the client's telephone number is coded into the certificate, which can not be changed even by themselves, both parties provide the other's telephone number.

In a further prefered application of the system according to the invention during the operation of the system in given case eg. an android base telephone, or telephone of similar capacity, which can handle a dataline, is necessary for the application, when joining the system the user buys the service at the website of the system, gets a code in a text message, on basis of which registration on the encrypted telephone on the website is possible, an important condition is, that a mobile subscription contract providing data supplying as well is necessary for it.

The solution according to the invention is set forth furthermore by the enclosed drawings/examples:

The Fig 1 shows the course of processing of the incoming orders.

The Fig 2 shows the initiation of the call.

The Fig 3 shows the course of the building up of the call.

The Fig 4 shows the course of registration from the side of the client and from the side of the center.

The Fig 5 shows the process of taking voice sample and playing during audio streaming processing.

The Fig 1 shows the course of processing of the incoming orders.

The Fig 1 shows the steps, respectively details of processing of the incoming orders below.

BI - Incoming information: telephone number, IMEI

TI- Is the telephone number already known? (DECISION)

UE - New subscription

FRJG - User^'s registration, generation password

FRMS - User's registration on the media server

UT - Issuing new certificate

FE - Informing user

LK - moving licence ? (DECISION)

URRT - registering new IMEI and deleting the old one

UTK - issuing new certificate

EM - renewing subscription

UJG - generating new password

UTK - issuing new certificate FE - informing user

The course of tele processing of the incoming orders takes place according to the Fig 1 ·. as described below.

The system handles the telephone number, respectively the IMEI code of the caller, as incoming information.

There is a decision point there: Is the telephone number known already, or not.

In case it is not known, No, then the system treats the caller as a new subscriber.

In case it is a new subscription, the registration of the user and generation of a password take place, as well as the registration of the user on the media server. Following this the issuing of the new certificate takes place and the information of the user.

In case the decision is yes, that is the telephone number, respectively IMEI code of the caller is already known for the system, then there is an additional deciding position regarding the moving of the licence.

In case the decision is Yes, then the registration of the new IMEI code takes place and the old one is deleted. Following this, the new certificate is issued and the user is informed.

In case the decision is No, then the subscription is renewed and new password is generated. Following this the new certificate is issued and the user is informed.

The Fig 2 shows the course of the initiation of the call.

The Fig 2 shows the steps, respectively details of initiation of the call below:

TB - writing in telephone number

TKT - looking up telephone number in the telephone directory

BHK - is a secure call initiated?

HHI - initiation of a traditional call

TN - normalizing the telephone number

BT - logging in with the telephone number

HFK - looking up called party from central database

BHL - is a secure call possible (DECISION)

HI - initiation of the call

HTj - error message: The called person has no subscription, or cannot receive a call

The initiation of the course of the call takes place according to the Fig 2 as described below.

The initiation can occur in two ways, one of them is writing in the telephone number, the other is looking it up in the telephone directory, and sending of it with the call button.

After the initiation of the call the system checks, if a secure call was initiated. In case the answer is No, then the system handles it, as if a traditional call was initiated, which is not handled furthermore as encrypted.

In case the answer is Yes, then the normalizing of the telephone number takes place and the logging in with the telephone number. During this the called person is checked in the central database, and the possibility of a secure call is decided.

In case the answer is Yes, then the call is initiated.

In case the answer is No, then the system generates an error message, saying, that the party called has no subscription, or can not receive a call.

Fig 3 shows the course of the building up of the call.

The Fig 3 shows the steps, respectively details of the course of the building up of the call below.

HF - calling party

HI - call initiation

TKE - reconciliation of encryption codes

HTK - sending of caller^'s certificate

HFL - party called

HTF - receipt of caller's certificate

HTE - is the caller's certificate valid? (DECISION)

HM - breaking of call

HTK - sending called party's certificate

HTTF - receipt of called party^'s certificate

HTTE - is the certificate of called party valid? (DECISION)

HM - breaking of call

TKCS - exchange of encryption code

HFSZK - displaying called party^'s number

KCST - calling

BE - conversation

TKCS - exchange of encryption code

HFSZK - displaying called party's number

KCSG - ringing

FO - is it going to be answered? (DECISION)

HE - refusal to take call

BE - conversation

The course of the building up of the call takes place as it can be seen in the Fig 3 described below.

First the initiation of the call takes place on the part of the caller, then the reconciliation of the encryption codes takes place and the sending of the caller^'s certificate to the party called.

The receipt of the caller's certificate takes place on the side of the party called, then a decision is made, during which the validity of the caller's certificate is checked. In case the caller's certificate is not valid, the call is broken.

In case the caller's certificate if valid, the certificate of the party called is sent to the calling party.

The receipt of the certificate of the party called takes place at the calling party, as well as a decision is made regarding the validity of the called party^'s certificate.

If the decision is No, the call is broken.

In case of Yes, the exchange of the encryption codes takes place on both sides, and following this comes the display of the number of the party called. Afterwards the system starts ringing at the caller's side, respectively the telephone rings at the called party.

At the called side the the party called decides then to receive the call or not. In case Not, then the call is refused. In case Yes, the conversation can start following this.

Fig 4 shows the steps, respectively details below of the course of registration.

JF - receipt of password

UFN -„opening of new folder" menu instruction

MTK - choosing„mobile encryption"

STJM - giving own telephone number and password

CAF - looking up CA

STJM - giving own telephone number and password

KG - generating password

TK - issuing certificate

TE - checking certificate

TR - registering certificate

TJR - registering telephone number and password

BTJ - logging in with telephone number and password

HKUM - displaying„ready for use" message

The course of registration at the client^' s side and at the central side takes place as shown in the Fig 4 described below.

First the receipt of the password takes place at the client's side, then the menu instruction„opening of new folder". Then choosing of the„mobile encryption" and the providing of their own telephone number and the password takes place. At the central side the looking up of Ca occurs, then giving the own telephone number and password.

At the client' s side generating the password takes place, resulting in the issuing of the certificate at the central side. At the client^'s side the checking of the certificate takes place, then the registering of the certificate and registration of the telephone number and the password follow. Resulting from this the logging in at the central side takes place. At the client's side the message„ready to use" is displayed resulting from this.

In a preferable concrete realization of the solution according to the invention the condition is to have a data line for the telephone line, primarily for the mobile phone line. During the application the telephone number is used in three different ways. The first use is the number itself which/what to be called. The second use is, that the telephone number is used as an user ID, working not only as a number, but an indentifier of an user as well. During this a digital certificate is issued for the users, where the telephone number is used as an identifier, so during the call the certificates of the conversing parners are checked, the telephone number is compared with the one the call is coming from. The identifiers are encrypted so, that they can not be falsified. When starting a call, a data call is started as well, checked by digital certificate. The password is generated by the user themselves, it is not recorded anywhere. The certificate is issued by the operator of the system.

When calls are arranged, there is a center, where they have to be registered. The coordination of the calls is similar to Skype, where there is a central users, registration, but the parties are in direct connection with each other. In case of the solution according to the invention however the data packages are encrypted with a digital certificate, so the ones having no code try in vain.

In case of the solution according to the invention the secure certificate is issued by the center, the center must be asked to issue the certificate. It means, that if there is no certificate, no logging in is possible, as the center does not allow the logging in,if the caller has no certificate. Without a certificate it is not possible for the parties to get into direct connection with each other. The users must identify themselves both toward the center and between the users with each other.

Technically the certificate of a data series is of abt. 1 Kbyte length, which is given by the center to the caller as a certificate at their first logging in. Furthermore at initiating each call a symmetrical password is generated, coded by the certificate and sent to the conversing partners. Afterwards they confirm it, and the conversation starts with this password.

It is an important circumstance, that the client^'s telephone number is coded into the certificate, which can not be changed even by the clients themselves. Both parties can see the other's telephone number on basis of this.

The system includes quite a few novelties:

Application platform

The aim is to establish an application making possible encrypted telephone

conversations. The application is made for a cordless manual mobile device platform and uses Internet as a connection. The application makes possible communication of IP base. The connection is made with central administration.

PKI based identification is used for both central logging in, and for the building up of the call. The certificate for the telephone and the telephone number is issued with the help of our own PKI system. It is not necessary for the user to appear in person, the possession of the telephone and the telephone number is checked with an one-time password sent to the telephone number. The private password is generated on the user s telephone and it never leaves it.

Verification of the caller

The caller is identified during the process of registration, and their telephone number is cryptographically registered in such a way, that the telephone number is built into the user^'s digital certificate.

After having logged in the central recording server and during the call the caller identifies themselves with the identifier referring to this number, which is impossible to counterfeit. The user's identity is checked twice, first by the center itself, second the by the conversing parties themselves. It is unique in itself from three aspects as well.

On the one hand, because other solutions do not include any call-controll, so however strange it might sound, the conversing partner can not be sure who they are talking to. In contrary to this, our solution checks and displays the conversing partner^'s number. On the other hand, other solutions are not able to check the protection of the line, so it might happen, that the line is manipulated and redirected. Our solution however checks cryptographically and indicates if the line is manipulated/redirected.

On the third hand, other solutions are not, or to a limited extent able to protect against built-in bugging. It generally happens in a way, that the application shows complex letter and digit rows on the device of both conversing partner, which is read to each other by the partners. Namely every conversation starts something like this:

Hullo, this is Nz/(F3 (so hullo, this is capital N small zee, dash, bracket opens capital F, three. - Yes and here is 8H+cP= (so hullo, this is eight capital H sign plus, small c, capital P, sign for equality)

Written down this might look funny, but in practice it can be carried out only with great difficulty, even if the partners are native speakers of the same language, in case of people with different languages it can frustrate starting conversation. The conversation might be encrypted, but it was resolved by a man-in-the-middle built into the line, recorded and newly encrypted and forwarded (this is the man-in-the-middle) attack. Our solution however filters out immediately and entirely transparently every attempt for building-in. Portability

Entitlement of the use of the system is attached to the telephone number and the telephone device, so it is not possible to copy it from one device to another. It is sure, that calls can be initiated from the very telephone and telephone number, which is actually in the possession of the user. In spite of this the entitlement is movable without breaching security. At the user" s request it is possible to move the entitlement from one device and/or number to another. This case the old certificate is disabled and a new one is issued instead, simultaneously checking if the telephone number is in the user^'s possession.

Transportation medium

The solution preferably uses mobile broadband Internet network to realize the encrypted conversations, resulting in a conversation of excellent quality.

The solution according to the invention, also in a preferable way is built into the telephone technically and logically as well, ensuring far-reaching transparent operation. Contrary to other solutions, where an application running on a telephone must be initiated and handled with own logics and own menu independently from the telephone, our solution is part of the telephone. It is important, that the operation of the telephone does not change, and the encrypted conversation behaves just like the traditional one. Namely the line indicates engaged if the telephone is busy, and rings if it is ready to receive a call, etc.

Transparency

In an advantageous way the user administration, the building up of the call and the realization of the call take place on the broadband network, entirely independently from the PSTN network. Still, the user can realize the call entirely in the traditional way, by dialling, or by choosing the phone number from the telephone register. According to this simple, but unique solution the user's real telephone number is used as identifier, both on the central recording server and the user^'s certificate. With this solution the difference between the PSTN and mobile Internet network disappears for the user.

Telephone number

The user identifier is the same as their telephone number, so by giving the traditional telephone number a transparent voip call can be initiated. The call goes through the Internet, but for the user it shows as an usual call.

IMEI number

It is important, that the certificate can not be copied and initiate a call from another device. The device must be at least stolen, but it is found out very quickly, but the copying is not.

Security level

No. l : the user is identified by their telephone number (SMS) and their bank card. No.2: the user must confirm their identity, that they are the owners of the number and the device. Group code

By this the user can be limited to a group, so eg. one person can speak in an encrypted way within their own company, with competitive companies not. Eg. a member of a political party can speak in an encrypted way within their own party, they can not leak information to a competitive party. There can be more group code at the same time.

The procedure of entering the system

The user buys the service in advance for a fixed period. It is necessary, because the certificates issued have an expiry date, and that can be synchronized with the time of subscription. Namely the certificate is valid until the client is a subscriber.

During the registration the user has to give the following details beside the data necessary for the payment:

1. The full telephone number together with the country code: (eg.: 0041781234567 or 0036301234567, etc.)

2. IMEI code

After the purchase the client gets a password. This is sent to them as a text message to the given telephone number. By this it is checked if the telephone number is really in their possession.

The client installs the application and starts registration with the registration" menu. The application asks for the telephone number and password during the registration. Then it generates a pair of password and a ring voice.

The user enters the CA through the CA (certificate authority) link, gives their telephone number as user^'s name, the password and the ring voice, that is the user^'s public password for signing. After a few seconds the certificate appears. Then it is downloaded, checked if the data (telephone number, IMEI code and the signature of the certificate) are identical, and in positive case the certificate is installed.

In case of a preferable concrete realization of the solution according to the invention the realization of the communication takes place in the voice transfer phase as follows:

The used data transferring protocole is: UDP (small header, quick, but uncontrolled data transfer.) The clients themselves ensure the buffering of the packages, rating, filtering, which is not granted by the UDP.

Data format: own Zybex packages, in which the encrypted audio and generally used password exchange protocole, in given case Mikey, SSL, TLS, etc. packages can be embedded. The format of the audio package is unique, however the generally used password exchange protocole packages are implemented in the part necessaiy, though exactly relating to the given protocole, required by RFC. Characteristics of Zybex package

Special characteristics:

• it does not include hash even for the sake of detecting discrepancies, as they are looked after by the own principles of the embedded packages (in case of audio eg.it is not important, but it can be several types with the generally used password exchange protocole)

• they are needed basically with describing character, because UDP

packages can be divided by the network devices resulting in problems in case of packages, that must be handled in one unit (eg.Generally used password exchange protocole)

• their maximum size is 512-8 byte, as there are a lot of small network devices, using MTU of characteristically 1500, but even 512-8 byte • it can include even more embedded packages (of identical type)

• respectively even that is possible, that an embedded package (characteristically Generally used password exchange protocole) can be compiled from several Zybex packages (group identifier, etc.)

The embedded audio acka e

Special characteristics:

• several pieces can be embedded into a Zybex package

• characteristic size (encoded, encrypted with headers) is abt. 50 byte (with a codec of 16 bites fixed with 8000kHz frequency of sample taking, able to code 160 samples in one package)

Characteristics of embedded Generall used assword exchan e rotocole

exchange protocole payloads generally used by us for sending certificates (

• Header

• Cert

« Timestamp

• HMAC

The generally used password exchange protocole payloads used by us for rekeying (in order):

• Header

• Timestamp

• RAND

• PKE

• KEMAC (with Key Data subpayload) Special characteristics:

• a Generally used password exchange protocole can be divided into more Zybex packages (eg.certificate)

• actually an embedded Generally used password exchange protocole package is a full Generally used password exchange protocole message, according to RFC given with more sub-packages (eg. header, timestamp, etc.)

Ingoing, resp. encrypting data applied with generally used password exchange protocole

Calculated from the

order number of audio

package, respectively

CSID from the valid package

index of the rekeying

information belonging

to the given CSB ID

Generated from TGK

TEK Not transferred!

with PRF

Audio-streaming

The route of a voice sample according to Fig 5 is the following:

Sample taking -> repeated sample taking- coding -> encrypting^ packaging - sending- receiving -> unpackaging -> decrypting - decoding -> repeated sample taking -> playing

Sample taking and playing:

Always what the given device supports! This is tested by the program in advance and it gives it a try with involving the smallest possible data stream resp. converting power. So with 8000, 16000, 24000, 32000, 11025, 22100, 44100 Hz, 16 bit, in monophonic. According to findings every device is able to record 8 kHz at 16 bit. During playing the code makes an attempt to 8 bit as well.

Buffering, preloading:

Preloading at starting: 3x250msec

Minimum preloading: 1 250msec (NO playing during this)

Loading during operation if the buffer has reached the miniumum: 2x250msec.

Data telecommunication and coding:

It takes place at fix 8kHz, 16 bit. If the given hardware does not support it, then preliminary (at sending) or subsequent (at receiving) repeated sample taking occurs from the recordable to fix definition, or from that to playable.

Encryption:

Symmetrical password calculated according to the generally used password exchange protocole with interim, or periodically renewed generating passwords.

The advantage of the solution according to the invention is, that in case of the system according to the invention, the system is simple and efficient, resulting from its use an actual telephone number as ID, eliminating the difference between different telephone systems. This circumstance is justified by a very strong encryption, which is easy to use and no installation is needed. It can already be used from the latest type of mobile phone, or if the user possesses an appropriate mobile phone. The access by the users^' s circle is relatively easy, because the user can build up the encryption and verification system to their own phone number. The system is transparent for the user, it is not apparent from the point of view of use, that they use an encrypted telephone. ·_;

In given case an eg. android base telephone, or a telephone of similar capacity is needed for the application, which is able to handle a dataline. When logging in to the system, the user buys the service at the website of the system, for which a code is given by a text message, allowing the registration to the encrypted telephone on the website. It is an important condition to have such a mobile subscription contract, that offers data supply service as well.

List of references: Fig l

BI - Incoming information: phone number, IMEI

TI- Is the phone number already known? (DECISION)

UE - New subscription

FRJG - User's registration, generating password

FRMS - User's registration on the media server

UTK - Issuing new certificate

FE - Informing user

LK - moving licence ? (DECISION) ^"

URRT - registering new IMEI and deleting the old one

UTK - issuing new certificate

FE - informing user

EM - Renewing subscription

UJG - generating new password

UTK - issuing new certificate

FE - informing user

Fig 2

TB - writing in phone number

TKT - looking up phone number in the phone register

BHK - is a secure call initiated?

HHI - initiating a traditional call

TN - normalizing the phone number

BT - logging in with the phone number

HFK - looking up called party from central database

BHL - is a secure call possible (DECISION)

HI - initiation of the call

HU - error message: The called person has no subscription, or cannot receive a call Fig 3

HF - calling party

HI - call initiation

TKE - reconciliation of encryption codes

HTK - sending of caller's certificate

HFL - party called

HTF - receipt of caller's certificate

HTE - is the caller^'s certificate valid? (DECISION)

H - breaking call

HTK - sending called party's certificate

HTTF - receipt of called party^'s certificate

HTTE - is the certificate of called party valid? (DECISION)

HM - breaking call

TKCS - exchange of encryption codes

HFSZK - displaying called party's number

KCST - calling

BE - conversation

TKCS - exchange of encryption code

HFSZK - displaying called party^'s number

KCSG - ringing

FO - is it going to be answered? (DECISION)

HE - refusal to take call

BE - conversation

Fig 4

JF - receipt of password

UFN -„opening of new folder" menu instruction

MTK - choosing„mobile encryption"

STJM - giving own phone number and password

CAF - looking up CA

STJM - giving own phone number and password

KG - generating password

TK - issuing certificate

TE— checking certificate

TR - registering certificate

TJR - registering phone number and password

BTJ - logging in with phone number and password

HKUM - displaying„ready for use" message

Claims

1. Encryption system for protecting phone calls, serving for the encryption of telephone calls, primarily for encryption of mobile telephone calls, said system uses the telephone network between the calling and called party, primarily mobile telephone network during the identification of the encryption, said system has data communication option, primarily mobile Internet service, beside realizing telephone conversations, characterized by that, during the operation of the system the user's telephone number is used in three ways,

- the first is the number itself to call from, or to be called,

- the second, the telephone number itself is used as an user's ID, functioning not only as a number, but also as an user's identifier,

- the third is to issue digital certificates for the users, where the telephone number is used as an identifier, and this way during the call the certificates of the conversing partners are checked, the telephone number is compared with the caller's number, as well as during the operation of the system a datacall is initiated simultaneously with the initiation of the call, which is checked with digital certificates, during which the password is generated by the users themselves, and said password is not recorded anywhere else, and the certificate is issued by the operator of the system,

2. System according to Claim 1 characterized by that, during the operation of the system the course of the processing of the incoming orders takes place in the steps described below,

3. System according to Claim 1 or 2 characterized by that, during the operation of the system the procedure of initiating a call takes place as described below,

the initiation can take place in two ways, one of them is the writing in of the telephone number, the other one is looking it up in the telephone directory and sending it with the call button,

after initiating the call, the system controls if a secure call was initiated,

in case Yes, then the normalization of the telephone, number takes place, and the logging in with the telephone number, during which the caller is checked in the central database, and it is decided if a secure call is possible,

if Yes, then the call is initiated,

4. System according to any of Claim 1 - 3 characterized by that, during the operation of the system the building up of a call takes place as described below,

during which first the initiating of the call takes place from the part of the calling party, then following this the reconciliation of the encrypting passwords and sending of the caller's certificate to the party called,

the receipt of the caller's certificate takes place on the side of the party called, then a decision is made, during which it is decided whether the caller^'s certificate is valid, in case the caller^'s certificate is not valid, then the call is cut off,

in case the caller's certificate is valid, then the forwarding of the certificate of the party called takes place to the calling party,

in case the answer is No, then the call is broken,

at the side called the party decides to receive the call or not,

if Not, then the call is refused,

if Yes, then conversation starts following this.

5. System according to any of Claim 1 - 4 characterized by that, during the operation of the system the course of registration of the client's side and the central side takes place as described below,

during which first the receipt of the password at the client's side takes place, then following the menu instruction „open new folder", then choosing of the „mobile encryption" follows, and giving the own telephone number and password follows, at the central side finding Ca follows, then giving of the own phone number and password, at the client's side password is generated, resulting in the issuing of the certificate at the central side, the certificate is checked at the client's side, then the certificate is fixed, then the telephone number and password are fixed, resulting in the logging in at the central side with phone number and password, resulting in the display„ready to use" message at the client^'s side.

6. System according to any of Claim 1 - 5 characterized by that, during the operation of the system there is a center, where one must be registered at a central user's registration, in order to realize the call, but the parties are in connection with each other, the data packages are encrypted with digital certificates.

7. System according to any of Claim 1 - 6 characterized by that, during the operation of the system the users must identify each other both toward the center and toward each other, on basis of the security certificate issued by the center, which means, that if there is no certificate, then logging in is not possible, and if the caller is not identified, the center does not allow logging in, furthermore without a certificate the parties can not get into direct connection with each other either.

8. System according to any of Claim 1 - 7 characterized by that, during the operation of the system the certificate is a dataseries of abt. 1 KByte length, which is given to the caller at the very first logging in by the center, furthermore a symmetrical password is generated at initiating every call, which is sent to the conversing partner coded with the certificate, then it is confirmed, and the conversation starts with this password.

9. System according to any of Claim 1 - 8 characterized by that, during the operation of the system the client's telephone number is coded into the certificate, which can not be changed even by themselves, both parties provide the other's telephone number.

10. System according to any of Claim 1 - 9 characterized by that, during the operation of the system in given case eg. an android base telephone, or telephone of similar capacity, which can handle a dataline, is necessary for the application, when joining the system the user buys the service at the website of the system, gets a code in a text message, on basis of which registration on the encrypted telephone on the website is possible, an important condition is, that a mobile subscription contract providing data supplying as well is necessary for it.