T 3.33 Improper use of cryptomodules

In practice, improper use of cryptomodules has already caused damage in many cases. This improper use can have various consequences.

• Data is not encoded before transmission because the plain-text mode in the cryptomodule was activated accidentally.

• When cryptographic codes are entered, parts of the code are entered incorrectly. The result is that neither the originator (who failed to notice the false entry) nor the recipient (who has no way of knowing the real code) can decode the data with the incorrectly-entered code.

• The electricity supply is accidentally cut off during the process of encoding the data. This has the result that only parts of the data are encoded while other parts are not. In such a case, it may no longer be possible to decode the data because the process was stopped due to an unforeseen error.

• Some of the encoding parameters are entered incorrectly. This can result in an insufficient number of secure cryptoalgorithms or insecure cryptographic codes being used.

• If the users are involved in producing the code, in that they are asked to enter random characters, it is also improper use to select strings of characters that are known or can easily be guessed (words) rather than random characters.

Such improper use of a cryptomodule can interfere with the confidentiality, the integrity and the availability of the data. Examples include:

• Data is not encoded or no longer encoded, even though it may be necessary to encode it to preserve confidentiality.

• Encoded data can no longer be decoded because improper use has made it impossible to use the cryptomodule in accordance with the rules.

• Data is either intentionally or unintentionally encoded in such a way that it can no longer be reconstructed because the necessary cryptographic code is not known.

• Correctly-encoded data is changed in such a way that the data can no longer be decoded