telesec chipcard operating system (DTAG, chipcard) (TCOS)

Telesec Chipcard Operating System (TCOS) is an operating system for chip cards developed by Deutsche Telekom AG. TCOS takes security-relevant functions into account, particularly those relating to authentication and secure data storage and transmission.

With TCOS, data is managed in a file system. For each file, TCOS provides different access rights and security mechanisms. In addition, data is protected by verifying the identity and authenticity of the user. For example, TCOS also relies on the Message Authentication Code( MAC), a cryptographic checksum.

Special attention is paid to the security of the signature key and identification data, as well as to the encryption of digital signatures. To create a secure digitalsignature, TCOS uses the RSA method. The digital signature can be generated according to the Public Key Cryptography Standard( PKCS#1) or the Home Banking Computer Interface( HBCI). Transmission between the smartcard reader and the smartcard takes place at transmission rates between 9.6 kbit/s and 460 kbit/s.

TCOS meets the requirements of the German Digital Signature Act(SigG) and the German Digital Signature Ordinance(SigV) and has been evaluated to Level E4 of the Information Technology Security Evaluation Criteria( ITSEC). It is used, among other things, in health insurance cards, which have no personal identification number( PIN) protection, and protects patient data against unauthorized reading.