This holds the fifth of eight possible 192-bit Triple DES transmit encryption keys, entered as a 48-character hex string. Mid-range slots like this one are typically reserved for routes added later in a deployment's life, since the first few slots often get used up during initial commissioning of the earliest routes. A new satellite link added to the network six months after initial deployment might be assigned key5 specifically because keys 1 through 4 were already committed to earlier routes.