Abstract: In order to secure data traffic between an external network and a mobile user terminal coupled to the external network, the terminal and a data securing device of the external network produce a pair of private external keys by exchanging partial keys. One item of key information based on at least one of the partial keys, and one message certified by the terminal with a first home location key of the pair of home location keys, are transmitted by the data securing device to the home location network. The certification of the message is verified with a second home location key of the pair of home location keys and a certificate is issued for the key information. The certificate thus provided is transmitted to the data securing device and the pair of private external keys is accepted, subject to the verification of the transmitted certificate, in order to secure data traffic.

Abstract: Data from a transmitter is extended to include authentication data on the application level by an application protocol. The authentication data is used by the receiver to determine whether the transmitter is known by the receiver. If the transmitter is known by the receiver, the data is accepted. If not, the data is rejected.

Abstract: In order to authenticate a first entity at a second entity, a first number is generated by way of an asymmetric cryptographic method. This first number is symmetrically encoded and transmitted to the second entity. The second entity checks the first number by decoding the second number and thereby authenticates the first entity.

Abstract: In order to secure data traffic between an external network and a mobile user terminal coupled to the external network, the terminal and a data securing device of the external network produce a pair of private external keys by exchanging partial keys. One item of key information based on at least one of the partial keys, and one message certified by the terminal with a first home location key of the pair of home location keys, are transmitted by the data securing device to the home location network. The certification of the message is verified with a second home location key of the pair of home location keys and a certificate) is issued for the key information. The certificate thus provided is transmitted to the data securing device and the pair of private external keys is accepted, subject to the verification of the transmitted certificate), in order to secure data traffic.

Abstract: A digital data stream comprises an arbitrary number of data block (Pn). For a data block, a first processing element (B1n) is provided that contains at least one first logic unit (VK1), an encryption unit (Ek), and a second logic unit (VK2). With the first logic unit (VK1), the respective data packet (Pn), at least one preceding data packet (Pn−1), and a preceding intermediate quantity (In−1) are combined and are encrypted in the encryption unit (Ek) to form the intermediate quantity (In). The intermediate quantity (In) is combined with a preceding cryptographically processed data block (Cn−l) to form the cryptographically processed data block (Cn).

Abstract: A method and system for transmitting data from a transmitter to a receiver, wherein data from a transmitter is extended to include authentication data on the application level by means an application protocol. Said authentication data is used by the receiver to determine whether the transmitter is known by the receiver. If the transmitter is known by the receiver, the data is accepted. If not, the data is rejected.

Abstract: In a method for cryptographic code management between a first computer unit and a second computer unit, the method is divided into individual modular phases. Authentification references that are employed in further cryptographic phases are exchanged during an authentification of the first computer unit and the second computer unit. As a result thereof and due to the modular structure, a respectively new authentification actually required in the further cryptographic phases is no longer necessary and is also not implemented.

Abstract: A group-based cryptographic code management method is proposed, in which a security policy which is used in a further communication is negotiated between group computer units and a first computer unit.