In one implementation a method of authenticating the installation of a television receiver involves generating a fingerprint value as function of the television network characteristics at an authorized installation location, where the fingerprint is a function of at least one of a gain value of a variable gain amplifier and an equalizer coefficient of an adaptive equalizer of the television appliance; receiving a code that is a function of both a decryption key and the fingerprint value from a broadcast source; ascertaining a value of the decryption key by applying an inverse function to the code that produces the decryption key as an output; and carrying out a decryption process at the television receiver appliance using the decryption key. This abstract is not to be considered limiting, since other embodiments may deviate from the features described in this abstract.