DE102008042406B4 - Process for the secure exchange of data - Google Patents

Abstract

A method for encrypted transmission of data (108) between communication subscribers, the communication subscribers comprising at least a sender (100) and a receiver (200), the method comprising the following steps:
Random selection of a pointer by the transmitter (100), wherein the pointer is uniquely associated with a seed of a set (132) of seed values,
Reading the pointer-associated start value by the transmitter (100),
Generation of a first key from the start value by the transmitter (100),
Providing a random second key by the transmitter (100),
Generation of a third key by the transmitter (100), wherein the generation comprises a combination of the first key with the second key,
Encrypting the data (108) with the third key by the transmitter (100),
Encrypting the second key and the pointer with a public key of the receiver (200) by the transmitter (100),
- Transfer of ...

Description

The The invention relates to a method for the encrypted transmission of data, a computer program product to carry out of procedural steps for the encrypted transmission of data from a Transmitter to a receiver, a computer program product for performing method steps for decryption from encrypted Data through a receiver and a portable data carrier.

Classic transmit hybrid encryption methods a symmetric, encrypted Plain text and with this an asymmetrically encrypted, symmetrical key. Succeed it, the transferred Intercept plain text data and / or the encrypted symmetric key, it is possible the attack on one of the two transmitted data elements, d. H. the encrypted Plain text or the encrypted key. Around an absolutely secure data transmission to ensure, have to therefore meets two requirements be, namely Firstly, no key may be transferred secondly, the plaintext must be provable with a theoretically encrypted secure procedure become.

These Requirements are met by the use of a one-time pad (OTP) Procedure fulfilled. The One-time pad method is a one-time encryption method which using only once used symmetric keys for secret messaging data encrypted. This requires that the communication partners have identical lists with pre-generated keys have them in a safe place. To the encrypted Communication of data selects so that the transmitter is one of the keys from the list of pre-generated keys, which encrypts the Data with this key and transmitted the encrypted Data together with an identifier that contains the key used in the pre-generated list identifies to the recipient. The receiver can then by means of the identifier in his list of pre-generated keys the corresponding associated key read out and thus a decryption process initiate the data.

For the one-time pad Method is proved (Shannon 1949) that encrypted data not decrypted can be as long as the relevant safety requirements are met. These are that the key fortuitously is the key the same length as the one to be encrypted Plain text is and the key used only once.

A decryption encrypted an OTP Textes is not possible because of the provable security because this method neither by technical (computing power) nor cryptographic (uncovering from security holes) Progress can be broken. It is therefore the only cryptographic Method that is secure in terms of information theory - assuming it is used as intended. That's why also simple and thus performant, encryption operations, z. B. XOR of the OTP key with to be used in plain language. The method is therefore provable sure, because an attacker could use any of the encrypted text, meaningful or not meaningful plain text of the same length with can produce the same hit probability. He can therefore never know which of the set of texts so generated originally encrypted Text is. An attack with brute force or other methods can therefore never succeed if the above safety requirements are met. Theoretically and provably However, OTP procedures are only certain if the key used is actually pure fortuitously is generated. Strictly speaking, this applies only to random numbers that from thermodynamic or quantum mechanical noise or the like Sources are generated.

Problematic When using an OTP method, that is for the warranty a high level of cryptographic security as noted above the keys only may be used once. However, this has the disadvantage that this method for data encryption then proves to be unsuitable if a large number of different Encryption operations to Communication with communication partners are performed got to. Either this requires a huge number of pre-generated keys distributed to the communication partners, or after exhaustion the pre-generated key would have to be in elaborately a distribution of new lists with pre-generated bowls to communication partners, but this is also due to the high security requirements an enormous logistical effort requires.

To solve this problem, suggests WO 00/67548 to use a method for encrypted communication using a one-time pad. The goal here is to recombine the pre-generated bowl of the one-time pad for each encryption process in a recursive derivable manner so that a final key is generated from it, with which a data encryption is performed.

Out DE 197 47 827 C2 a method for the encrypted transmission of data between communication participants is known, wherein in ei nem transmitter from a start value ("initialization value") of a first key is generated. The receiver also generates a corresponding decryption key from the start value.

Out DE 101 58 003 B4 For example, a method for generating keys is known. It describes that both at a transmitter and at a receiver of encrypted data starting values ("initial values") are respectively stored, to which pointers refer. A pointer is transmitted from the transmitter to the receiver for selection of the corresponding start value.

Out EP 1 304 827 A1 For example, a secure method of transmitting data from a transmitter to a receiver using first, second and third keys is known.

In contrast, lies The invention has the object, an improved method for encrypted transmission from data transmitter to receiver, an improved computer program product and an improved disk to disposal to deliver.

The The objects underlying the invention are each with the Characteristics of the independent claims solved. Preferred embodiments of the invention are in the dependent claims specified.

The The invention relates to a method for the encrypted transmission of data between Communication participants, wherein the communication participants at least a transmitter and a receiver The method first comprises the step of Choice of a random one Select a pointer by the transmitter, the pointer being unique is associated with a seed of a set of seed values. This is followed by reading the start value associated with the pointer by the transmitter, a generation of a first key from the Start value by the sender, providing a random second key by the sender, using a third key generation a link the first key with the second key through the sender, the encrypting the data with the third key through the sender, the encrypting the second key and the pointer with a public key of receiver through the transmitter. After all follows the transfer the encrypted data and the encrypted second key and of the encrypted Pointer through the transmitter to the receiver.

On the receiver side reception of the encrypted Data and the encrypted second key and the encrypted Pointer, the decrypting of the encrypted second key and the encrypted Pointer with the private key Recipient, reading the pointer associated start value by the Receiver, the set of seed values being known to the sender and the receiver is, a generation of the first key from the starting value by the recipient, the generation of the third key using a link the first key with the second key through the receiver and after all the decryption the data with the third key through the receiver.

In In another aspect, the invention relates to a computer program product to carry out of procedural steps for the encrypted transmission of data from a Transmitter to a receiver, the procedure being first the step involves the random Choosing a pointer, where the pointer is unique with a seed a set of seed values, the sentence of Start values the transmitter and the receiver is known. Further includes the method comprises the step of reading the starting value associated with the pointer and generating a first key from the seed. Of Another becomes a random second key provided and a third key generated using a link the first key with the second key. In other words, the third key is around a one-time pad. The to be encrypted Data is encrypted with the third key and for transmission to the recipient provided. Also provided is the second key and the pointer. It should be noted that the second key in the specialist terminology also referred to as "salt" becomes.

This can be done in two different ways:
Either the first key corresponds to the seed, in which case the third key is generated by a pseudo-random number generator, the first key associated with the second key being the seed value of the pseudo-random number generator. Alternatively, the first key is generated by a pseudo-random number generator, the seed being the seed value of the pseudo-random number generator, the first key thus generated being associated with the second key to produce the third key used for encryption.

The computer program product according to the invention for carrying out method steps for the encrypted transmission of data has the advantage that the starting value is used in a cryptographically secure manner for a multiplicity of different encryption processes can, without the need to mark the start value used as "used" in the list after each encryption process in order to exclude it from any further use. The reason is that for each encryption operation a different "salt", ie another randomly chosen second key, is used so that the third key used for data encryption is modified at each encryption operation.

Preferably after providing the encrypted data and the second key and the pointer for transmission to the recipient the second bowl and transmit the pointer in a cryptographically secure manner to the recipient, so that unauthorized persons are unable to get the second key and catch the pointer in plain text.

This requires a further advantage, namely that of a plurality of Participants the set of starting values to carry out encryption can be provided without the risk that at an encryption process twice the same third key / start value is used. This is because each of the participants due to the random Choice of salt, d. H. of the second key, using a different second key, so that the multiplicity of participants each have identical starting values for encryption can use without the risk that other participants to whom the second key not transmitted will, a decryption process based on the starting value or the pointer, which with the starting value connected is, perform can.

As already noted, according to one embodiment of the invention comprises The method further comprises the step of encrypting the second key and of the pointer. Preferably, asymmetric cryptographic encryption methods are used here for use. For example, it is possible for the second key and the pointer with the public key Recipient encoded will, so that exclusively the recipient, which is in possession of his private key is the encrypted one second key and decode the pointer, finally the third key to extract.

To an embodiment According to the invention, the first key corresponds to the starting value, the Generation of the third key by a pseudo-random number generator, the one with the second key linked first key of the Seed value of the pseudo-random number generator is. According to one embodiment The invention will be for the first and second keys through an XOR link and / or summing each other to obtain this seed value connected. According to one embodiment the invention goes for this to generate the third key the bit length the one to be encrypted Enter data into the generation.

To a further alternative embodiment the invention is carried out by the generation of the first key a pseudo-random number generator, the seed being the seed value of the pseudo-random number generator. A pseudo-random number generator is used here because a true random number generator "only implemented in hardware could be for example, by sampling a noise signal or the cosmic Background radiation. This would However, require a considerable technical effort, so that here preferably cryptographic pseudo-random number generators which do not use 100% cryptographic security Completely, but approximately reachable. Furthermore, the use of a pseudo-random number generator has the Advantage that this software z. B. can be formed so that both on the transmitter and on the receiver side the same pseudo-random number generator can be provided or the same random number can be generated. Thus, both the transmitter as well as the receiver side capable of using the Seed value seed value as the pseudo-random number generator operate so that both sender and receiver the same first key obtained using the same seed value.

To an embodiment In this case, the first and the second keys pass through the invention an XOR link and / or a summation or other mathematical operation linked together to obtain the third key. Such a linkage of first and second key to receive the third key has the advantage of receiving the third key with minimal processing power can be.

According to a further embodiment of the invention, the bit length of the third key corresponds at least to the bit length of the data to be encrypted. As noted above, this increases cryptographic cryptographic security because, for example, by exclusive-ORing (XOR) the individual bytes of data with the third key, maximum cryptographic security can be obtained if the bit length of the third key is the bit length of the corresponds to encrypted data. This is one of the hallmarks of the OTP procedure, according to which a key that is as long as the encryption key is used Message itself.

To a further embodiment of the invention, when the generation of the first key by a pseudo-random number generator takes place, the bit length of the first key at least the bit length the one to be encrypted Data, where the bit length the one to be encrypted Data in the generation of the first key from the start value is received. For example, a pseudo-random number generator can be used in which, in addition to the starting value as a seed value additionally the bit length the one to be encrypted Data is received, whereupon the pseudo-random number generated from the seed value in their length individually to the entered bit length of the to be encrypted Data is adjusted.

To a further embodiment invention, the method is an e-mail communication method, the method further comprising the step of receiving a recipient list comprises, wherein the elements of the recipient list the names and / or E-mail addresses and / or identifiers and / or the asymmetric keys of receiver comprising, the set of seed values known to the recipients is. This makes it possible efficiently encrypted e-mail communication with receivers perform, by sending a message to a recipient of the recipient list based on the recipient list the corresponding recipient e-mail address and its preferably public Key to be selected to then encrypted with the third key Data to this e-mail address to ship, along with the preferably with an asymmetric Key, preferably the public key Recipient, encrypted second key and pointers.

To a further embodiment According to the invention, the method comprises the step of electronic Signing the encrypted Data by the consignor which enables a consignee to verify the authenticity of the received communication message.

To a further embodiment of the invention is the set of seed values and / or the recipient list in a password-protected memory area stored on a portable data carrier, the method comprising the steps of accessing the storage area of the disk by means of a password and the reading of a starting value and / or an element of the recipient list from the storage area.

In In another aspect, the invention relates to a computer program product to carry out of procedural steps for decrypting encrypted Data through a receiver, where the method comprises the steps of receiving the encrypted Data and a second key and a pointer from a transmitter, the pointer being unique to is linked to a seed of a set of seeds, the set of seed values being known to the sender and the receiver is. Furthermore, the method comprises the step of reading the linked to the pointer Start value and the generation of a first key from the start value. thereupon becomes a third key created using a link of the first key with the second key and there is a decryption the data with the third key.

To a further embodiment According to the invention, the method further comprises the step of a signature verification in Case of that the encrypted Data are electronically signed.

In In another aspect, the invention relates to a portable data carrier Means of implementation of procedural steps for the encrypted transmission of data from a Sender to a receiver.

In In another aspect, the invention relates to a portable data carrier Means of implementation of procedural steps for decrypting encrypted Data through a receiver.

at such a disk For example, it could be a flash memory. For example, this could be a USB flash drive, a Compact Flashcard (CF) with a memory Stick (MS) to a Multi Media Card (MMC) to a Secure Digital Memory Card (SD) to a Smart Media Card (SMD) or an xD-Picture Card (xD).

To a further embodiment According to the invention, the portable data carrier has a public key infrastructure on. This makes it possible issuing, distributing and reviewing digital certificates. In addition, this allows public Bowl of recipients to safely import from external databases at the same time to be able to do so using digital certificates the authenticity from such public keys too to verify.

According to a further embodiment of the invention, the portable data carrier is a portable data processing unit, wherein the method steps for decrypting the encrypted data and / or the method steps for encrypted transmission of the data are performed by the data processing unit. For example, the data processing unit may be a processor chip card or a mobile telecommunications device, such as a mobile device. B. a mobile phone or a personal digital assistant (PDA) act.

in the Below are embodiments of Invention explained in more detail with reference to the drawings. Show it:

1 a block diagram of an e-mail communication system for secure transmission of data,

2 a flowchart for methods for encrypted transmission of data from a sender to a receiver and for decrypting encrypted data by a receiver,

3 a hierarchical structure in which communication participants are assigned to different groups.

The 1 shows a block diagram of an exemplary e-mail communication system, which in the present case from the main components of data processing system 100 , USB stick 102 , Data processing system 200 , USB stick 202 and network 150 consists. This form the data processing system 100 and the USB stick 102 the sender side, whereas the data processing system 200 and the USB stick 202 form the receiver side. Usually, the network 150 be assigned to a variety of other data processing systems and possibly portable media. This is preferably the case with the network 150 around the internet. However, this can also be an intranet of a company network.

In the following, it is assumed without restriction of generality that the components described below, which are on the USB sticks 102 respectively. 202 are included in corresponding memory areas for portable data carriers, generally flash memory, are provided. However, it is possible that all these components, ie the components 114 to 134 or the components 214 to 240 , also on the data processing system 100 or the data processing system 200 may be included.

The sender side, ie the data processing system 100 includes input means 102 and a processor 104 which is able to be in the store 106 execute contained programs. The input means may be, for example, a keyboard, a mouse, haptic input means, speech input means as well as any kind of scanners with which biometric features can be detected. Further in the store 106 contained are to be encrypted data 108 , By means of an interface 112 is the data processing system 100 capable of doing so over the network 150 with another data processing system 200 or its interface 212 to communicate. Another communication option is the training of the interface 112 in addition as a USB interface, allowing communication with the USB stick 102 is possible.

Finally, the memory points 106 another program in the form of an e-mail client 110 on which it is possible to send or receive e-mails.

Now to a cryptographically secure data transfer from the data processing system 100 to the data processing system 200 The procedure is preferably as follows:
Using the data processing system 100 or the input means 102 and a display element, not shown here, such as a screen, a user accesses the USB stick 102 to. Preferably, this requires that the USB stick is unlocked by means of a password. In addition, preferably the USB stick or should be on the USB stick in the protected memory area 114 be signed data to immediately detect any manipulation of the software or data. Either requires access to the protected storage area 114 the entry of a password or the protected memory area comprises a computer program product 116 which contains a program which initiates a corresponding authentication process. For example, this can be done using an Access Control program. 128 respectively. Only after a user faces the program access control 128 authenticated, it is possible by means of this program or program module, on other modules, such as an encryption module 130 , Signing modules, OTP tables, etc., to access. As already noted, the tamper resistance is increased by adding either the access control program 128 is signed and / or the other modules 118 to 126 . 130 as well as the tables 132 and 134 signed.

An access control could be done by simply entering a password. However, it is also possible to provide access control using biometric features using the input means 102 in the data processing system 100 entered.

After the access control by means of the module 128 was successful, is determined by means of the pointer selection module 120 coincidentally a pointer of the sentence 132 selected from starting values. In the present example, it is assumed without restriction of generality that the pointer "1" is selected, which is the starting value "XYZABCD ..." in the table 132 assigned. This start value then becomes the pseudo-random number generator 118 entered as the seed value, from which the pseudo-random number generator 118 generates a first key. Preferably, the bit length of the data also goes into this key generation 108 one that is to be encrypted.

This is done with the help of the module 122 a generation of the second key, this second key also being a pseudo-random value. Preferably, the bit length of this second key also corresponds to the bit length of the data to be encrypted 108 , By means of the linking module 124 is then the means of the pseudo-random number generator 118 generated first key with the second key, for example, using an XOR operation linked, which finally results in a third key.

It should be noted, however, that in an alternative embodiment, the seed "XYZABCD ..." can be used directly, preferably with the module 122 linked second key. This link value then becomes the pseudo-random number generator 118 entered as the seed value, from which the pseudo-random number generator 118 generated the third key. Preferably, the bit length of the data also goes into this key generation 108 one, which should be encrypted.

By means of the encryption module 130 can now view the data 108 be encrypted with this third key. The encrypted data is then sent to the e-mail client 110 pass, so now send the encrypted data to the data processing system 200 over the network 150 is possible.

In order to later decrypt the encrypted data, it is necessary that the data processing system 200 , which is intended to decrypt the data, comes into possession of the first and second key. Only in this way is it possible to generate the third key with which a decryption process of the encrypted data can be performed symmetrically. For this it is sufficient to the data processing system 200 to transmit the second key used for encryption and the pointer used for encryption. The reason is that for decryption the data processing system 200 also access to the table 132 has what is described in detail below.

Instead of the second key and the pointer in plain text using the e-mail client 110 to the data processing system 200 is preferably in the protected memory area 114 of the USB stick 102 a recipient list 134 held to each recipient, which is also in possession of the list 132 with seed values, which assigns its e-mail address and public key to an asymmetric cryptographic key pair. Such as in the 1 the recipient "Maier" is assigned an e-mail address and the public key "123abcxyz". So should from the data processing system 100 An e-mail with the encrypted data will be sent to this user, using the from the table 134 the public key of the recipient "Maier" encrypted both the second key and the pointer, which is used to encrypt the data 108 previously used. The second key and pointer thus encrypted with the public recipient key is used together with the encrypted data by means of the e-mail client 110 to the receiver, ie the data processing system 200 , over the network 150 transfer. The encryption is preferably also carried out by the encryption module 130 ,

It should be noted that it is alternatively possible to use the database 134 outsource externally. For example, the database 134 Be part of a public key infrastructure that can be accessed publicly.

After using the e-mail client 110 the encrypted data and the encrypted second key and the encrypted pointer to the data processing system 200 transmitted and received there may be at the data processing system 200 a decryption process take place. For this purpose, the data processing system 200 in a similar way as the data processing system 100 input means 202 , a processor 204 , a store 206 with an email client 210 as well as an interface 212 on. By means of the interface 212 Again, it is possible with a USB stick 202 or the network 150 to communicate.

Access to the USB stick 202 takes place as already described in detail regarding the access to the USB stick 102 explained. This is again served by the access control 228 , After successful access is a user of the data processing system 200 able, first, by means of his private key 240 which together with the corresponding public key of the table 134 (for example, "123abcxyz") forms an asymmetric cryptographic key pair, a decryption operation of the encrypted second key and the encrypted pointer, which together with the encrypted data are contained in the email sent by the data processing system 200 was received. After this decryption process succeeded, you can now use the extracted pointer over the table 132 the corresponding starting value "XYZABCD ..." are read into the pseudo-random number generator 218 given to generate the first key. As mentioned above, the pseudo-random number generator must 218 with the pseudo-random number generator 118 be identical.

After the first key has been created, this first key can be used by the private key 240 extracted second key to obtain the third key with which the data received by the e-mail is encrypted. By means of the decryption module 230 Now a data decryption can be made by means of the third key.

Again, however, it should be noted that in an alternative embodiment, the starting value "XYZABCD ..." can be used directly, and preferably with the reference to the private key 240 extracted second key is linked. This link value then becomes the pseudo-random number generator 118 entered as the seed value, from which the pseudo-random number generator 118 generated the third key. By means of the decryption module 230 Now also a data decryption by means of the third key can be made.

Optional is the use of the module 226 to verify a signature of the received e-mail. It is further noted that communication between the data processing system 100 and the data processing system 200 also via other communication methods instead of e-mail communication. Data can be encrypted via FTP, HTTP or various other protocols.

To illustrate the security of the communication method shown, assume in a first scenario that a third data processing system is connected to the network 150 connected, and also in the possession of the table 132 is. Even if this third data processing system unauthorized access to the means of the data processing system 100 encrypted data, this third data processing system will not be able to decrypt this encrypted data. Try all possible OTP keys of the table 132 would not lead to data decryption because the data is not encrypted solely with the OTP keys but with a third key provided by linking the OTP key to a second key individually generated for each communication transaction. In other words, the data processing system could 100 , the data processing system 200 and said third data processing system using the same OTP key to communicate with each other without an unauthorized recipient being able to do so due to ownership of the table 132 to perform an unauthorized decryption process.

Furthermore, it should be noted that in a second scenario, assuming that an unauthorized person would be able to crack the asymmetric encryption of the second key and the pointer or was in the unlawful possession of the recipient's private key, this unauthorized user would not would be able to decrypt the encrypted data as well. This would require that unauthorized user to access the table 132 to have. Since preferably this OTP table 132 Thus, an unauthorized user would have to have "physical access" to the OTP table, except that it is local to the authorized users of the communication method and is also preferably physically separate from the data processing systems used by the users 132 gain. Since this is not to be assumed, the unauthorized user would have to try a large number of different combinations of the second key with randomly selected first keys to decrypt the encrypted data using the cracked second key, thus obtaining the third key with which the data is encrypted , However, since, as already noted, preferably the bit length of the first key and preferably also of the second key are equal to the bit length of the data to be encrypted, this requires a computing power, as will be hardly available for such a decryption process, however, especially for larger amounts of data An attacker can use the encrypted text to generate any meaningful or meaningless plaintext of the same length with the same hit probability. Thus, the described cryptographic method for encrypting and decrypting data is classified as cryptographically highly secure.

It should be noted that the portable data carrier 102 respectively. 202 instead of a USB stick, it may generally also be a data processing unit in the form of a processor chip card, all of the connections and resolutions Lungsvorgänge be carried out exclusively on the smart card itself by means of the processor of the chip card. This ensures that at no time neither the first key nor the OTP key of the list 132 , any program elements, such as the pseudo-random number generator, the linking module or the module for generating the second key can get into the hands of unauthorized users. All calculations take place exclusively on the processor chipcard itself and the processor chipcard itself merely supplies to the data processing system 100 or to the data processing system 200 the third key with which the data can be encrypted and decrypted.

The 2a and b show flowcharts for encrypting and decrypting data. The procedure for encrypting data begins in 2a with step 300 , selecting one of the starting values of a set of starting values via a randomly selected pointer, for example a list number N. Thereafter, by means of a pseudorandom number generator in step 302 a pseudo-random number Z, ie the first key, generated, the in step 300 selected starting value S serves as a seed.

Follow this step 304 with the generation of a pseudo-random number "salt", the second key. This salt as well as the in step 302 generated pseudo-random number Z are in the step 306 to obtain the third key, for example using an XOR link. Finally, in step 308 an encryption of the data with the in step 306 obtained third key. The data so encrypted will be in step 310 transmitted to the recipient. In addition to the recipient is sent in step 310 the salt, ie the second key, and the list number N, the salt and the list number preferably being encrypted with the recipient's public key.

According to an alternative embodiment, the step 302 passed over and in step 306 not the pseudo-random number Z, but directly the starting value S associated with the salt to obtain a seed value. This seed value is then in step 306 used to generate the third key by means of a pseudo-random number generator.

It it should be noted that the encryption and the mail structure with separate programs done to the OTP key in to use a secure environment.

The decryption process in step 310 transmitted data is in the flow chart in the 2 B explained in more detail. The decryption process begins in step 312 with the reception of the encrypted data as well as the encrypted salt and the encrypted list number N. The salt and the list number N are encrypted with the public recipient key. This allows the recipient in step 314 to decrypt the salt and N by means of his private recipient key. With the list number N thus obtained, the receiver is now able to read out of the set of start values that starting value S, which in step 318 to generate the pseudo-random number Z as a seed value. As already mentioned, the pseudorandom number Z is the first key. This first key will step in 320 with the in step 314 decrypted salt linked, for example, again via an XOR link. This gives the recipient in step 320 the third key with which a decryption process of the encrypted data in step 322 is carried out.

When using the alternative embodiment mentioned above, the step 318 passed over and in step 320 again not the pseudo-random number Z, but directly the starting value S with the salt linked to obtain a seed value. This seed value is then in step 320 used to generate the third key by means of a pseudo-random number generator.

Encrypting the data in step 308 or decrypting the data in step 322 can be implemented, for example, by means of an XOR link due to the same bit length of the data to be encrypted and the third key used for encryption. For this purpose, the message to be encrypted is first encoded as a bit sequence and linked bit by bit with the third key XOR. Because preferably in the steps 302 and 318 In addition to the selected starting value S as seed and the length of the encrypted or decrypted data received, it is ensured in all cases that this incoming bit length is identical for both the encryption and the decryption process. This is necessary because only in this way can it be guaranteed that in the steps 302 respectively. 318 generated pseudo-random number Z (first key) is identical in both cases.

The 3 shows a hierarchical structure in which communication participants are assigned to groups. The hierarchical structure of 3 is subdivided into different hierarchy levels A, B, C and D. Each hierarchy level has a number of groups 400 to 428 on, where a group of different participants can be assigned. It is important now that communication participants are hierarchical in groups 400 to 428 are divided, where groups the same hierarchical level fundamentally different sets of Startwer ten, ie different OTP lists. In 3 Each individual OTP list is assigned an individual value between 1 and 8 by way of example.

Another principle is that a superordinated group is provided with all sets of starting values (OTP lists) which are assigned to groups in hierarchy levels which are subordinate to the superordinate group. In other words, a given group gets provided all sets of seed values which are assigned to subordinate groups at lower hierarchy levels. This is now an example on the basis of 3 explained in more detail:
Starting from the lowest hierarchical level D, this hierarchical level D has eight different groups. These are the groups 414 to 428 , Each of these groups gets different sets of seed values, ie different OTP lists, provided. So has the group 414 or their communication participants, only access to the OTP list 1 while the group 416 only access to the OTP list 2 Has. The OTP list 418 only has access to the OTP list 3 , the group 420 only has access to the OTP list 4 etc.

The hierarchy level C is superior to the hierarchy level D. In the hierarchy level C, there are now the groups 406 . 408 . 410 and 412 , The group 406 are the groups 414 and 416 subordinate. The group 408 are the groups 418 and 420 subordinate. The group 410 are the group 422 and 424 subordinate to the group 412 are the groups 426 and 428 assigned. According to the rules mentioned above, this has the consequence that the group 406 which the groups 414 and 416 parent, access to the OTP lists of groups 414 and 416 Has. In other words, the group has 406 Access to the OTP lists 1 and 2 , The same applies to the group 408 which the groups 418 and 420 is parent, so the group 408 Access to the OTP lists 3 and 4 of the groups 418 and 420 Has. The same principle can easily be applied to the groups 410 and 4120 continue.

In the hierarchy level B, which is superior to the hierarchy level C, the groups are now located 402 and 404 , The group 402 is the groups 406 and 408 superior, whereas the group 404 the groups 410 and 412 assigned. Again, according to the rules above, the group now has 402 Access to the OTP lists showing the subordinate groups 406 and 408 are assigned. These are the case of the group 406 the OTP lists 1 and 2 and in the case of the group 408 the OTP lists 3 and 4 , Accordingly, the group 402 the OTP lists 1 . 2 . 3 and 4 assigned. Regarding the group 404 can easily be seen that the group 404 the OTP lists 5 . 6 . 7 and 8th assigned.

The hierarchy level B is superordinate to the hierarchy level A, in which only the single group 400 located. According to the above rules are the group 400 the OTP lists 1 . 2 . 3 . 4 . 5 . 6 . 7 and 8th provided as the group 400 the groups 402 and 404 is superior.

This now has the consequence that an encrypted communication according to the in the 1 and 2 addressed OTP encryption method is never within a hierarchical level A, B, C or D is possible, but basically along a branch from each other parent or subordinate hierarchy groups. For example, it is possible for the hierarchy group 400 with all subordinate hierarchy groups 402 to 428 can communicate in an encrypted way. The hierarchy group 406 can work with both the parent groups 402 and 408 communicate as well as with subordinate hierarchy groups 414 and 416 ,

The application of such a hierarchical grouping and distribution of OTP keys can be explained by way of example on the basis of the hierarchically structured management structure in a company and the resulting communication requirements. For example, this is the hierarchy level A, ie the top hierarchical level in the group 400 , the communication participant assigned to "management". Group communication participants should be able to communicate with each employee in a secure manner. Because of this, this group has 400 Access to all OTP lists 1 to 8th ,

In the hierarchy level B with the groups 402 and 404 can now be assigned to these groups different areas, ie the groups 402 and 404 Different area managers are assigned. Each area is divided into different departments, so that the hierarchical level C with their groups 406 to 412 corresponds to the departmental level, with each of the groups 406 to 412 different department heads are assigned. These departments are again subordinate to the individual employees, so that these employees in the hierarchy level D the groups 414 to 428 assigned.

The likelihood that one of the many level D employees leaves the company is much greater than the likelihood that one of the lower level C executives, one of the even lower level B directors, or one of the staff of the company Management of the hierarchy level A, leaving the company.

In the event that any of the level D employees leaves the company, it is desirable that this employee be unable to participate in any way in the company's e-mail traffic. For this purpose, it is sufficient to exchange the corresponding OTP list in the hierarchical level D in the respective group to which the employee was assigned. For example, assume that the employee in the hierarchy level D of the group 414 was assigned. Thus, it is enough, the OTP list 1 against a new OTP list 1' replace what is in the group 414 as well as in the parent groups 406 . 402 and 400 must be made. This means a minimal logistical effort to change the OTP lists, since such a change in case of a departure of an employee of hierarchy level D only has to be made in a total of four individual groups. Only in the unlikely event that a department manager of hierarchy level C leaves the company, it is necessary to change the OTP lists in all superordinate as well as in all subordinate groups. Divorces, for example, a department head, which of the group 406 is assigned from the company, so must in the groups 400 and 402 . 406 . 414 and 416 the OTP lists 1 and 2 against corresponding new OTP lists 1' and 2 ' be replaced.

For the even more unlikely case, according to which a divisional manager of hierarchy level B leaves the company or to which one participant of the management group 400 As the company leaves, the logistical effort for redistributing OTP lists increases, as in the example of the 3 in the case of leaving a participant of hierarchy level B, a total of eight groups of OTP lists must be exchanged, and in the case of one participant, the group 400 leaves the company, 15 groups need to be provided with new OTP lists.

Summarized can thus in a simple manner by means of the method shown above the assignment of participants to hierarchically organized groups a small group of communication participants from the communication be excluded, but not for the majority of participants, which assigned to other groups, a logistically complex exchange from OTP lists. This significantly reduces management overhead for list management without however, that loses to be accepted in safety.

It however, note that in the most general form there is no hierarchy needed but only a set of disjoint lists with seed values. It is important here that communication partners who are at the same Circle of communication partners belong to each other safely below Use of the communication method according to the invention should communicate, the same lists provided to get. This makes it possible Build matrix structures.

100

Data processing system

102

input means

102

USB stick

104

processor

106

Storage

108

dates

110

E-mail client

112

interface

114

storage area

116

A computer program product

118

Pseudorandom number generator

120

module for pointer selection

122

module for generating the second key

124

linking module

126

signature module

128

access control

130

encryption module

132

OTP List

134

recipient list

150

network

200

Data processing system

202

input means

202

USB stick

204

processor

206

Storage

210

E-mail client

212

interface

214

storage area

216

A computer program product

218

Pseudorandom number generator

224

linking module

226

signature verification

228

access control

230

decryption module

240

private key

400-428

group

Claims (32)

Method for the encrypted transmission of data ( 108 ) between communication participants, wherein the communication participants at least one transmitter ( 100 ) and a receiver ( 200 ), the method comprising the steps of: randomly selecting a pointer by the transmitter ( 100 ), where the pointer is uniquely associated with a starting value of a sentence ( 132 ) is linked by starting values, - reading by the sender the starting value associated with the pointer ( 100 ), - Generation of a first key from the starting value by the transmitter ( 100 ), - providing a random second key by the transmitter ( 100 ), - Generation of a third key by the sender ( 100 ), wherein the generation comprises linking the first key to the second key, - encrypting the data ( 108 ) with the third key through the transmitter ( 100 ), - encrypting the second key and the pointer with a public key of the recipient ( 200 ) by the transmitter ( 100 ), - transmission of the encrypted data and the encrypted second key and the encrypted pointer by the sender ( 100 ) to the recipient ( 200 ), Receiving the encrypted data and the encrypted second key and the encrypted pointer by the recipient ( 200 ), - decrypting the encrypted second key and the encrypted pointer with the private key of the recipient ( 200 ) by the recipient ( 200 ), - read by the receiver the start value associated with the pointer ( 200 ), where the set of seed values is the transmitter ( 100 ) and the recipient ( 200 ), - Generation of the first key from the start value by the recipient ( 200 ), - generation of a third key by the recipient ( 200 ), wherein the generation comprises linking the first key to the second key, - decrypting the data with the third key by the recipient ( 200 ). The method of claim 1, further comprising the step of distributing the set ( 132 ) of start values to the communication subscribers, wherein - the number of communication subscribers has at least three different groups, - the subscribers of the first and second group receive a first set of start values, - the subscribers of the second and third group receive a second set of start values and the first and second sets of starting values are disjoint to one another. The method of claim 1 or 2, further comprising the step of distributing the set ( 132 ) of start values to the communication subscribers, wherein - the communication subscribers are hierarchically grouped ( 400 - 428 ), groups of the same hierarchical level receive different sets of starting values, each of the groups is provided with all sets of starting values which are assigned to the relevant group of subordinate groups in lower hierarchy levels. Computer program product for performing method steps for the encrypted transmission of data ( 108 ) from a transmitter ( 100 ) to a recipient ( 200 ), the method comprising the following steps: random selection of a pointer, wherein the pointer is unambiguously associated with a starting value of a sentence ( 132 ) of seed values, the set of seed values being sent to the sender ( 100 ) and the recipient ( 200 ), - reading the starting value associated with the pointer, - generating a first key from the starting value, - providing a random second key, - generating a third key, wherein the generation comprises a combination of the first key with the second key, - Encrypt the data ( 108 ) with the third key, - providing the encrypted data and the second key and the pointer for transmission to the recipient ( 200 ). The computer program product of claim 4, wherein the The method further comprises the step of encrypting the second key and of the pointer. The computer program product of claim 5, wherein the second key and the pointer will be encrypted with an asymmetric key. Computer program product according to one of the preceding claims 4 to 6, wherein the first key corresponds to the start value, wherein the generation of the third key by a pseudo-random number generator ( 118 ; 218 ), wherein the first key associated with the second key is the seed value of the pseudo-random number generator ( 118 ; 218 ). Computer program product according to one of the preceding claims 4 to 6, wherein the generation of the first key by a pseudo-random number generator ( 118 ; 218 ), the starting value being the seed value of the pseudo-random number generator ( 118 ; 218 ). The computer program product of any one of the preceding claims 4 to 8, wherein the first and second keys are XORed and / or a summation are linked together to obtain the third key. Computer program product according to one of the preceding claims 4 to 9, where the bit length the third key at least the bit length the one to be encrypted Data corresponds. The computer program product of claim 10, wherein to generate the third key the bit length the one to be encrypted Data enters the generation of the third key. Computer program product according to one of the preceding claims 8 to 10, where the bit length the first key at least the bit length the one to be encrypted Data equals the bit length of the to be encrypted Data in the generation of the first key from the start value is received. A computer program product according to any one of the preceding claims 4 to 12, wherein the method is an e-mail communication method, the method further comprising the step of receiving a recipient list ( 134 ), whereby the elements of the recipient list ( 134 ) comprise the names and / or email addresses and / or identifiers and / or the asymmetric keys of the recipients, the set of seeds being known to the recipients. Computer program product according to one of the preceding claims 4 to 13, the method further comprising the step of electronic Signing the encrypted Dates. Computer program product according to one of the preceding claims 4 to 14, wherein the set of starting values and / or the recipient list ( 134 ) in a password-protected storage area on a portable data carrier ( 102 ), the method further comprising the steps of: - accessing the memory area ( 114 ) of the data carrier by means of a password, - reading a start value and / or an element of the recipient list ( 134 ) from the storage area. Computer program product for carrying out method steps for decrypting encrypted data by a receiver ( 200 ), the method comprising the steps of: receiving the encrypted data and a second key and a pointer from a sender ( 100 ), where the pointer is uniquely associated with a starting value of a sentence ( 132 ) of seed values, the set of seed values being sent to the sender ( 100 ) and the recipient ( 200 ), - reading the starting value associated with the pointer, - generating a first key from the starting value, - generating a third key, wherein the generation comprises linking the first key with the second key, - decrypting the data with the third key , The computer program product of claim 16, wherein the received second key and the received pointer are encrypted and the procedure further comprising the step of decrypting the second key and of the pointer. The computer program product of claim 17, wherein the received second key and the received pointer are asymmetrically encrypted. Computer program product according to one of the preceding claims 16 to 18, wherein the first key corresponds to the start value, wherein the generation of the third key by a pseudo-random number generator ( 118 ; 218 ), wherein the first key associated with the second key is the seed value of the pseudo-random number generator ( 118 ; 218 ). Computer program product according to one of the preceding claims 16 to 18, wherein the generation of the first key by a pseudo-random number generator ( 118 ; 218 ), the starting value being the seed value of the pseudo-random number generator ( 118 ; 218 ). Computer program product according to one of the preceding claims 16 to 20, wherein the first and the second key by an XOR link and / or a summation are linked together to obtain the third key. Computer program product according to one of the preceding claims 16 to 21, where the bit length the third key at least the bit length the one to decrypt Data corresponds. The computer program product of claim 22, wherein to generate the third key the bit length the one to decrypt Data enters the generation of the third key. Computer program product according to one of the preceding claims 19 to 22, where the bit length the first key at least the bit length the one to decrypt Data equals the bit length of the to be decrypted Data in the generation of the first key from the start value is received. The computer program product of any one of the preceding claims 16 to 24, wherein the encrypted data is electronically signed, the method further comprising the step of signing over Examination of the signed encrypted data. Computer program product according to one of the preceding claims 16 to 25, wherein the set of starting values and / or the recipient list ( 134 ) in a password-protected storage area on a portable data carrier ( 202 ), the method further comprising the steps of: - accessing the memory area ( 214 ) of the data carrier by means of a password, - reading a start value from the memory area. Portable data carrier ( 102 ) with means for performing method steps for the encrypted transmission of data ( 108 ) from a transmitter ( 100 ) to a recipient ( 200 ), the data carrier comprising: - a sentence ( 132 ) of starting values, wherein the set of starting values belongs to the transmitter ( 100 ) and the recipient ( 200 ), - means ( 120 ) for a random choice of a pointer, wherein the pointer is uniquely associated with a starting value of a sentence ( 132 ) of starting values, - means for reading the starting value associated with the pointer, - means ( 118 ) for generating a first key from the starting value, - means ( 122 ) to provide a random second key, - means ( 124 ) for generating a third key using a link of the first key to the second key, - means ( 130 ) for encrypting the data ( 108 ) with the third key, - means for providing the encrypted data and the second key and the pointer for transmission to the recipient ( 200 ). Portable data carrier ( 202 ) with means for performing method steps for decrypting encrypted data by a receiver ( 200 ), the data carrier comprising: - a sentence ( 132 ) of starting values, wherein the set of starting values belongs to the transmitter ( 100 ) and the recipient ( 200 ), means for receiving the encrypted data and a second key and a pointer from a transmitter ( 100 ), where the pointer is uniquely associated with a starting value of a sentence ( 132 ) of starting values, - means for reading the starting value associated with the pointer, - means ( 218 ) for generating a first key from the starting value, - means ( 224 ) for generating a third key using a link of the first key to the second key, - means ( 230 ) to decrypt the data with the third key. Portable data carrier ( 102 . 202 ) according to claim 27 or 28, wherein the data carrier comprises a flash memory (eg USB stick, CompactFlash card (CF), Memory Stick (MS), Multimedia Card (MMC), Secure Digital Memory Card (SD) , Smart Media Card (SMD), xD-Picture Card (xD)). Portable data carrier ( 102 . 202 ) according to one of the preceding claims 27 to 29, wherein the portable data carrier has a public-key infrastructure. Portable data carrier ( 102 . 202 ) according to any one of the preceding claims 27 to 30, wherein the portable data carrier ( 102 ; 202 ) is a portable data processing unit, wherein the method steps for decrypting the encrypted data and / or the method steps for encrypted transmission of the data ( 108 ) by the data processing unit. Portable data carrier ( 102 . 202 ) according to claim 31, wherein the data processing unit is a processor chip card or a mobile telecommunication device.