T 5.81 Unauthorized use of a cryptomodule

If a third party manages to use an encryption module in an unauthorised manner, different kinds of damage may be the result. Examples of such damage include the following:

• During unauthorised use, the attacker manages to read secret keys, to change the keys, or to manipulate critical security parameters. The consequence would be that the cryptographic procedures no longer provide sufficient security.
• During unauthorised use, the attacker manipulates the encryption module in such a way that it works properly at the first glance, but is actually in an insecure condition.
• The attacker uses the encryption module as a form of masquerade. If the attacker signs or encrypts data while using the encryption module in an unauthorised manner, the recipient of the data interprets the signature or encryption as if the authorised user signed or encrypted the data.

Example:

• An unauthorised use of the encryption module is possible if the regular user leaves his/her workplace for a short period of time and the functional encryption module can be used without it being protected against unauthorised access, i.e. if a signature or encryption chip card remains in the computer, for example. This way, any person who happens to pass by may sign emails in the name of the regular user or encrypt data stored to the IT system in such a way that the user can no longer use it.