-
- Add a new key to the list of trusted keys. The key is read
- from <replaceable>filename</replaceable>, or standard input if
- <replaceable>filename</replaceable> is <literal>-</literal>.
+ Add a new key to the list of trusted keys.
+ The key is read from the filename given with the parameter
+ &synopsis-param-filename; or if the filename is <literal>-</literal>
+ from standard input.
+ </para>
+ <para>
+ It is critical that keys added manually via <command>apt-key</command> are
+ verified to belong to the owner of the repositories they claim to be for
+ otherwise the &apt-secure; infrastructure is completely undermined.
+ </para>
+ <para>
+ Instead of using this command a keyring can be placed directly in the
+ <filename>/etc/apt/trusted.gpg.d/</filename> directory with a descriptive name
+ (same rules for filename apply as for &apt-conf; files) and "<literal>gpg</literal>"
+ as file extension.