Appendix · Random number generators
This chapter discusses one of the least glamorous but most security-critical components in physical cryptography: the random number generator. It distinguishes deterministic generators from non-deterministic, physically based generators and explains why only the latter are suitable for high-assurance QKD and MKD scenarios. Special emphasis is placed on BSI-oriented security levels and the difference between availability-driven and randomness-quality-driven design priorities.
The chapter also develops a concrete attack scenario involving manipulated random number generators. It shows that bit streams may pass statistical randomness tests even if they are fully predictable to an attacker, making supply-chain and device trust essential. From there, the text derives recommendations for maximum security and notes that entanglement-based QKD and RKD reduce dependence on external random generators because randomness is more intrinsic to the method itself.
Further sections explain technical variants of TRNGs, interfaces such as USB and PCIe, practical product examples, speed estimates for large MKD key volumes, and the broader market context. The chapter thereby links abstract randomness requirements with procurement, throughput, and deployment reality.
- Distinguishes deterministic and true randomness
- Explains standards and security requirements
- Describes attacks using manipulated generators
- Surveys interfaces, products, and bit rates
- Connects RNG speed directly to MKD feasibility