System for establishing a cryptographic key depending on a physical system

A cryptographic system for reproducibly establishing a reproducible code word comprising

• a physical system comprising a physical, at least partially random, configuration of components,
• an initial bit-string producer for establishing an initial bit-string (310), the initial bit-string (310) depending on the configuration,
• a normalizer for establishing in dependency on the initial-bit string a first correctable bit-string, the first correctable bit-string lying in a correctable neighborhood of an error correcting code, a pre-determined error correcting algorithm for mapping an element of the correctable neighborhood to a code word being associated with the error correcting code,
• an error-corrector, for establishing a first code word of an error correcting code in dependency on the first correctable bit-string using the error correcting algorithm,
• wherein
• the cryptographic system further comprises a randomizer for producing a randomizing component
• the establishing of the first correctable bit-string is further dependent on the randomizing component, and
• the cryptographic system further comprises a transformer for transforming the first code word into the reproducible code word, the transforming being dependent on the randomizing component for making the reproducible code word reproducible by removing the effect of the randomizing component.

A cryptographic method for reproducibly establishing a cryptographic key comprising

• establishing an initial bit-string (310), the initial bit-string (310) depending on a physical, at least partially random, configuration of components comprised in a physical system,
• establishing in dependency on the initial-bit string a first correctable bit-string, the first correctable bit-string lying in a correctable neighborhood of an error correcting code, a pre-determined error correcting algorithm for mapping an element of the correctable neighborhood to a code word being associated with the error correcting code,
• establishing a first code word of an error correcting code in dependence on the first correctable bit-string using the error correcting algorithm
• establishing the cryptographic key in dependency on the first code word by applying a pre-determined key derivation algorithm,
• wherein
• the method further comprises producing a randomizing component,
• the establishing of the first correctable bit-string is further dependent on the randomizing component, and
• the establishing of the cryptographic key is further dependent on the randomizing component for making the cryptographic key reproducible by removing the effect of the randomizing component.