From an email posted to Baen's Bar Honorverse dated June 1, 2005:

Grav pulse comm intercepts

    Someone has begun speculating about the possibility of successfully tapping into the opposition's grav-pulse FTL communications net. Is this a possibility?

     

    It's theoretically possible. Up until very recently, there wasn't any reason for Manticore to worry about it, since no one else had any FTL communication capability. As other star nations begin to develop the grav-pulse com, that's going to change. However, by the same token, the ability to encrypt transmissions will grow in sophistication as bandwidth and the general sophistication of the grav-pulse transmissions grow. In other words, while it will become theoretically possible, the practical chance of anyone successfully breaking into the other side's FTL communications loop in a fashion which provides any sort of real-time tactical advantage is remote.