For the realization and introduction of autonomous vehicles, the safe
interaction of functions, systems and services as well as their monitoring over
the entire product life cycle is essential. An exclusive security-by-design
approach is no longer sufficient and must be continuously supported by feedback
obtained from in-the-wild operation. This is where the recently successfully
completed joint project BMBF UNCOVER comes into play, which targets the
requirements of the standards ISO/SAE 21434 (Road vehicles – Cybersecurity
engineering) and ISO 21448 (Road vehicles – Safety of the intended
functionality (SOTIF)).
In symmetric-key cryptography, we typically distinguish two types of encryption
schemes: block ciphers and stream ciphers. Block ciphers divide a plaintext into
blocks of a fixed size (e.g., 64 or 128 bits) and encrypt one such block of data
as a whole. Stream ciphers, on the other hand, consider the plaintext as a
continuous stream of data. The stream cipher maintains an internal state and in
each step it outputs one bit or several bits and updates its internal state. The
output bit stream is then combined with the plaintext, usually using the XOR
operation. One advantage of stream ciphers is that their resource requirements
are lower than those of block ciphers in many application scenarios. This makes
them particularly useful in lightweight cryptography targeting resource
constrained devices such as low-cost RFID tags.