Tapping cables

In October 1971, a US submarine, Halibut, visited the Sea of Okhotsk off the eastern USSR and recorded communications passing on a military cable to the Khamchatka Peninsula. Halibut was equipped with a deep diving chamber, fully in view on the submarine's stern. The chamber was described by the US Navy as a "deep submergence rescue vehicle". Once submerged, deep-sea divers exited the submarine and wrapped tapping coils around the cable. Having proven the principle, USS Halibut returned in 1972 and laid a high capacity recording pod next to the cable. The technique involved no physical damage and was unlikely to have been readily detectable.

1. 1. Intelligence agencies have spent a great deal of money on research into tapping optical fibres, reportedly with little success. But long distance optical fibre cables are not invulnerable. The key means of access is by tampering with optoelectronic "repeaters" which boost signal levels over long distances. It follows that any submarine cable system using submerged optoelectronic repeaters cannot be considered secure from interception and communications intelligence activity.

1. Intercepting communications

1. Using optical telecommunication technology