Until they become unambiguously compromised, the nuke subs are probably the scariest weapons in our arsenal. No enemy wants his whole society reduced to a smoking glass crater ...
Also ...
Also ...
Russia has successfully fired an intercontinental ballistic missile from a submerged submarine, military officials said.[upi.com]And furthermore ...
To establish a secure link while remaining 100 metres underwater, submarines could transmit photons of laser light to satellites, for retransmission to base. With the key exchanged, the submarine could then communicate via laser pulses with guaranteed security.[newscientist.com]