CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to German Patent Application No. DE 10 2019 212 959.5, filed on Aug. 28, 2019 with the German Patent and Trademark Office. The contents of the aforesaid Patent Application are incorporated herein for all purposes.

TECHNICAL FIELD

The invention relates to a method for protected communication between a vehicle and an external server. The external server may for example be a backend server of the vehicle manufacturer or of a service provider to whom the vehicle manufacturer has granted the corresponding authorization. The invention furthermore relates to a device for performing the key derivation in the method, as well as a correspondingly equipped vehicle.

The invention relates to the field of data security in the digital age. From the technical field of cryptography, various techniques are known for encrypting and securely exchanging data. The main goals of protecting databases are confidentiality (access protection), integrity (change protection), authenticity/forgery protection and liability (non-reputability). The invention will be explained using the example of secure data exchange between a modern vehicle and an Internet service provider. In this context, there are various challenges.

BACKGROUND

This background section is provided for the purpose of generally describing the context of the disclosure. Work of the presently named inventor(s), to the extent the work is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.

Asymmetric keys are currently the basis for secured communication, such as TLS communication between vehicles and back-end servers of Internet service providers. A typical example is HTTPS communication that is used to realize a secured Internet link in browsers.

Such encryption methods will become worthless as of time X. Time X is the date on which so-called quantum computers with certain properties become available. An enormous boost in computing power is anticipated through them because significant parallelism in computing operations as possible by means of the superposition principle that they use. The introduction of these quantum computers will also affect the methods of cryptography because it will make some encrypting methods vulnerable. The associated problem is also termed the post-quantum challenge in the professional world.

From today's perspective, one potential solution is envisioned in securing all communication with different backend servers on the Internet as of time X only with 256 bit symmetrical cryptography. In doing so, the encrypting algorithm AES 256 could be used with 256 bit keys corresponding to the advanced encryption standard. With the introduction of AES 256, 2254.4computing steps are required according to the best currently known encrypting algorithm. Even with the first two generations of quantum computers, this would not be possible within an acceptable time.

It is therefore currently assumed that in the future, 256 bit keys will be introduced into vehicles that will be used for secured data exchange.

SUMMARY

With symmetrical cryptography, a problem may however exist that the same keys must also be revealed to the particular Internet service provider. This is associated with a security risk, and a large number of vehicle-specific keys must be distributed. There is therefore a need to improve key administration for the various Internet service providers.

The aforementioned methods authenticate software to be imported, but not the establishment of authenticated communication.

An object thus exists to reduce the security risk when using the symmetrical cryptography method for solving the post-quantum challenge (PQC).

This object is solved by a method for protected communication by a vehicle with an external server, by an electronic device for performing key derivation, and a vehicle according to the independent claims.

Embodiments of the invention are discussed in the dependent claims and the following description.

The details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features will be apparent from the description, drawings, and from the claims.

