Probabilistic error analysis of encrypted transmission for safety-related railway applications

The paper deals with the problem of probabilistic error analysis of an encrypted transmission used within safety-related control system for applications with increasing safety integrity level (SIL). The requirements to cryptographic block code in safety-related communications for railway application are describe. The main part is oriented to description of mathematical apparatus for the error probability of the cryptography block code for the communication system on the end-to-end with GSM-R communication channel. The practical results are related with the quantitative evaluation of an average error probability of the cryptography code for several lengths of safety - related message which are expanded with determination of the cryptography degradation with using GMSK modulation scheme.