Method and encryption system for secure data transmission

The present invention relates to a method for secure transmission of messages between at least two users of a telephone communication network. they also relates to an encryption system for performing this procedure and the accompanying technical Institutions.

By the penetration of computers in almost all Areas of life and their increasing interconnectedness by large-scale telecommunications networks is the power of Traffic between computers of various kinds enormously increased. Many of the information exchanged is confidential and you and / or may be used by unauthorized Third can not be read, so that a large Need for cryptographic security of this Traffic is. Simple cryptographic methods but do not hold a cryptanalysis using computers standing, so that a great interest in Encryption method is that even with a Use of computers using novel Decryption methods are safe.

The same applies to an exchange of information at Telephoning or faxing, as the latest by an insert Computer technology in conjunction with automatic Word recognition techniques both in industry and in the private sector virtually any on public Transmission channels Gone word easily recorded, can later be searched and analyzed again. At least Private people are currently such a change in its Privacy still virtually defenseless, because of a sufficient accessibility to appropriate Encryption or decryption process and to corresponding devices for carrying out this Method is missing. In addition, unauthorized third parties at a Much of the usually regarded as relatively safe known encryption methods by a very large Computational complexity and / or novel decryption come into possession of the information exchanged, what theoretically, by a government seizure of the would key used possible.

As absolutely safe with respect to a decryption attempt apply computer application, currently only Encryption methods in which the transmitter and Receiver of a message respectively the same secret random key is used, which as long as the Message itself and only once to encrypt is used.

The object of the present invention is to Provide a process for producing such individual secret random key and the exchange of generated key between at least two users of an Telecommunications network, to information exchanged, whether by phone, fax or PC, eavesdropping on encrypt. The task is also to provide an encryption system for carrying out this Method and the accompanying technical facilities.

This object is by the in claim 1 dissolved specified method, preferred refer 12 - embodiments subclaims 2 are.

An encryption system for carrying out this Method is to claim 13 can be seen, while in the Claims 14 to 19, preferred embodiments are claimed.

Special features and advantages of the invention Encryption method, the inventive Encryption system for carrying out this method and the associated technical equipment of the system arising from the following detailed Description of an embodiment, which in the the accompanying Fig. 1 is shown schematically.

Fig. 1 shows a key generator 10 for generating a random binary key of great length, in the present embodiment by means of a (not shown) built-in optical random with Beam splitter is generated, as for example, the German patent application 196 41 754.6 is apparent. It However, a random generator may be employed, wherein the or the spontaneous emission of a photon in electrically optically excited matter or radioactive decay to Key generation is used. It is also conceivable Using a physical process or a noise other appropriate physical process.

The generated key is then no internal storage built by a (not shown) Writer in the key generator 10 in at least two transportable data or key carrier 12 enrolled and in this form a Benuzter output, wherein the number and possibly also the type of issued data carriers by means of a (not shown) input keyboard by the user free is selectable. As disk 12 can in this case, as in the present case be used CDs. The key can However, for example, on magnetic tape, on suitable Semiconductor memories or other appropriate stored portable storage device and be issued.

The key generator 10 is open to the public to possible broad target groups a cryptographic to enable secure their communications. It should therefore as many key generators 10 are comprehensively installed, taking care to is that the body that the conditions laid down devices 10 care, a certain confidence enjoys, so as For example, at the post office is the case. This is the Risk of tampering with the devices 10 and the Probability that the key also to unauthorized Third comes and this the key to a specific can assign person, relatively low.

Anonymity at the key issue, and thus the Security of the encryption method is further increased so that the key generators 10 preferably by Coin or by entering a Specialty Payment means, such as a corresponding Magnetic stripe card, are easily activated, without any the user must identify this or any data Magnetic stripe card are stored.

However, it is also conceivable for big companies such as in Connection with leased lines the entire Communications with a receiver, such as a Subsidiary or a branch to the specified type and encrypt way. In this case, it is worth using a private key generator 10, which then in the each company is installed and there the Company members, or even a limited is select group of individuals who for itself Hedging of risk only by entering a must identify personal identification number.

Given the tremendous progress in the art, it is However, also conceivable that the key generators 10 mentioned type in the future so inexpensive and compact be prepared that it also for individuals are affordable and in large numbers also input Find in households.

The number of specified disk 12 is a (Not shown) input keyboard can be selected so that they the Number of the communicating user corresponds. When a transmitter and a receiver are thus two Disk 12 is output, on each of which the same random key is recorded and of which the Transmitter and receiver setup each a disk 12 receives. The transfer of the data carrier 12 can in this case For example, personally or by sending by post done. A secure key exchange can also be Using a suitable key distribution system take place, as those skilled in the art For example, under the designation "quantum cryptography" is known.

To encrypt a message, the media are 12 from users now entered in reading means 14, the the by users, ie the sender of a message and the associated receiver of the message, for used messaging Telecommunication transmission devices 16, such as telephones, , Each associated with fax machines or PCs and for reading the key used in each of the disks serve.

The proper key entry and the Match the key entered by users will be checked by means of logistic facilities 18, to those used for messaging Telecommunications transmission venue 16 also allocated are and automatically when a connection contact accommodate each other.

The logistics means 18 synchronize the Encrypt or decrypt a message, the Key at the transmitter and receiver, or portions thereof Key and ensure that encryption only previously unused portions of the random key to the Key sources are used 12th This is done to For in that used parts of a key Are defaced deleted, or that the body used on the disk up to the back of the key has been, is stored.

Encrypting a message to be transmitted binary takes place for example simply by the key in Binary code added to the message (modulo 2) and the resulting random sequence followed by a associated transmission means 20 via a Transmission line 22 to the respective receiver Gets transferred. From incoming encrypted messages is the random key again subtracted and thus the Message decrypted. Subsequently, the message the supplied phone, fax, etc. of the recipient will. If a key is completely processed, then at each key generator 10, a new, unlike any other Key matching keys are related, the is then in turn also used only once.

The reading means 14 and 18 Logistikeinreichtung can be very small and easy to run, so that they individually or also in a combined Means even be integrated in portable handsets can, what the scope of the invention Process enormously expanded.

In exchange talks on the phone has the Encryption, transmission and decryption carried out during the conversation and in the pauses, so that may latch necessary to collect news items before the transfer. These but individual components are already normal Transmissions, and codes and for reading and Recording of communications required.

If a sender of messages with multiple recipients would correspond eavesdropping, it can for each of these Connections use a private key, which in turn respectively recorded on two identical disks 12 is, of which get the transmitter and receiver each one. In order here to keep order, the various Disk 12 with the keys in a device are inserted, the individual keys selected recipients assigns. It comprises a Receiving means for the various key support 12 and automatically selects when connecting the right that contains the same key that the selected recipients scored. Are the Key carrier CDs, the device resembles a disc changer in a jukebox. The assignment of the individual keys can in this case be carried out either manually by the user or but by a logistics unit of the device itself, before establishing a connection with the Against logistics means of a receiver comes into contact, the inserted key support and key checks and automatically the corresponding key carrier or Key selects. The reading of the keys of the Key supports 12 is also here in turn means an integrated reader.

It is also conceivable that both recipient and sender is on have a corresponding device, into each of multiple disks 12 loaded with keys to either in a predefined sequence to be processed in sequence or in one of Logistics means the transmitter specific random Order, then the counter with the logistics facility Recipient is contacted to where the insertion of a Disk to initiate with the same key.

Since the random key invention in which Methods recorded only on the key supports 12 be and also the transmission and reading means 20 or 14 are not disclosed, and even the once Encrypting a message to be used is the Process by an unauthorized third party even with large Computational effort and the use of modern Decryption practically impossible to break long the key carrier 14 with the keys not in unauthorized Hands reach, evidenced by appropriate precautions is relatively easy to prevent.