1. The Beginning of Submarine Cables

The first submarine cable was laid in the English Channel in 1851. The cable, which was mistaken for a new kind of seaweed, was quickly severed and became unusable the next day, but the idea spread rapidly. About 20 years later, in 1872, with the laying of submarine cable between Nagasaki, Japan and Shanghai, China, Japan was incorporated into the global network of submarine cables. The laying of submarine cables became a key national policy at that time.

In the latter half of the 19th century, Western countries actively advanced overseas. Submarine cables were used as a tool for overseas expansion. In 1881, King Kalakaua of Hawaii, which was an independent kingdom, visited Japan and requested the construction of an underwater cable between Japan and Hawaii, but Japan, being in the middle of the political upheaval of Meiji 14 (1881), could not meet this request. At the beginning of the 20th century, 60% of the world's undersea cables were owned by the British Empire or its state-owned companies. Hawaii was the last place on the Pacific route to which the British Empire was trying to connect, but it was blocked by the United States, which had great interest in Hawaii. When the Spanish-American War broke out in 1898 and the United States acquired the Philippines and Guam, it became necessary to secure a route from the west coast of the United States to Guam, and as a result Hawaii was annexed to the United States. Submarine cable installation to Hawaii became a challenge, but it was accomplished without government subsidies by businessman John W. Mackay.

Hawaii and undersea cables played an important role in raising US interest in the Pacific. For 100 years, submarine cables have been associated with geopolitical factors.

2. Submarine Cables and War

When World War I broke out, Britain issued a declaration of war on Germany and, as soon as it came into force, severed German submarine cables in the North Sea. The purpose was to block much of Germany's communications and to divert them to Sweden, a neutral country, in order to facilitate wiretapping.

During World War II, wireless telegraphy was often used in addition to wired communications. As a result, the role of telegraph undersea cables has relatively declined, but it is no exaggeration to say that wiretapping determined the outcome of the war. The interception and breaking of the Japanese Purple code and the German Enigma code are well known.

As many undersea cables had been destroyed in World War II, wireless communications were used extensively after the war. However, since wired communications were harder to intercept than wireless communications, the remaining wired undersea cables were also used. As the Cold War intensified, Operation Ivy Bells was launched in the Sea of Okhotsk to intercept Soviet submarine cables. Submarine cables at that time used copper wire as the core and, when a communication signal ran through the cable, a weak signal was emitted from the cable. The United States installed equipment on Soviet seabed cables to monitor the signal, and regularly collected the equipment to analyze the data. The Soviet Union did not even encrypt communications in such places, not realizing they would be intercepted. However, a Soviet spy in the US government notified the Soviet Union of the US' wiretapping of the submarine cables, and the Soviet Union reportedly recovered the equipment.

In the 1980s, the technology to put optical fibers instead of copper wires in the core of cables was established, and communication capacity increased dramatically. The signals flowing through the cable were changed from electrical signals to optical signals, making it impossible to intercept submarine cables at the bottom of the sea like in Operation Ivy Bells.

3. Changes in Operational Domains

In June 2013, Edward Snowden, who worked at the National Security Agency (NSA) facility on the island of Oahu in Hawaii, handed over top-secret NSA documents to journalists, revealing some of the Agency's activities. In the leaked documents we found a description of programs called PRISM and UPSTREAM. It is believed that the former meant acquiring data from platform companies such as Google, while the latter meant acquiring information on submarine cables. Although it is extremely difficult to intercept optical fiber cables at the bottom of the sea, the NSA is believed to have been able to intercept signals on land with the cooperation of telecommunications carriers. The NSA has not confirmed the authenticity of the leaked information, but it appears to be part of a larger surveillance of communications by the US government since the 9/11 terrorist attacks in 2001.

Since around 2010, the US military has regarded space as its fourth operational domain and cyberspace as its fifth, in addition to the conventional operational domains of land, sea, and air. However, unlike the other four operational areas, cyberspace is an artificial domain. Cyberspace consists of physical entities such as communication terminals (PCs and smartphones), wired and wireless communication lines connecting them, and data centers that contain servers.

As long as they are physical, they can be physically damaged or destroyed. In fact, many submarine cables have been damaged by fishing nets, anchors and earthquakes. In 2013, a submarine cable was intentionally severed in Egypt. In 2015, the New York Times reported that "Russian submarines and spy ships are aggressively operating near the vital undersea cables" and in 2019 Admiral James Stavridis (retired) argued that "China's next naval target is the Internet's underwater cables", thus raising awareness that submarine cables could become targets for destruction.

4. Submarine Cable Industry

Looking at the submarine cable industry, Subcom in the United States holds around 40% share in the manufacturing of submarine cables, NEC in Japan (via its affiliate OCC) roughly 30%, Alcatel-Submarine Networks (ASN) in Europe approximately 20%, and Hengtong Optic-Electric (which acquired Huawei's submarine cable division) in China less than 10%. In addition to the importance of the cables themselves, vessels for laying and repairing submarine cables, power feeding equipment (PFE) and submarine line terminal equipment (SLTE) in landing stations are also important factors in considering the safety of submarine cables.

Amid growing interest in submarine cable security, one case that garnered attention was the suspension of the PLCN (Pacific Light Cable Network). The cable, which was owned by Google and Facebook in the US and the Dr. Peng Telegraph & Media Group in China, was intended to connect to Hong Kong across the Pacific from Los Angeles on the US West Coast. However, as the trade and technological friction between the United States and China as well as the demonstrations in Hong Kong intensified, the US government refused to allow the landing in Hong Kong. The PLCN was changed to land in the Philippines and Taiwan.

Then, in August 2020, US Secretary of State Mike Pompeo announced the "Clean Network" project to exclude Chinese products from US apps, the cloud, submarine cables and elsewhere.

Communication monitoring is a measure implemented and emphasized by countries seeking to improve their cyber security capabilities. For example, at the 2012 London Olympic and Paralympic Games, the US NSA collaborated with the UK Government Communications Headquarters (GCHQ) to share signal intelligence (SIGINT). This measure reportedly included monitoring of submarine cables.

5. Summary

Submarine cables are strategic assets for governments in the information age. Since digital transformation (DX) is a key technology for the future economy, submarine cables based on clean technology are an indispensable element, and they are even more important for Japan, an island country that relies on submarine cables for 99% of its international communications.

It goes without saying that the Japanese government must exercise caution in monitoring communications bearing in mind the secrecy of communications (Article 21 of the Constitution and Article 4 of the Telecommunications Business Law). However, in order to prevent cyber attacks and communications-aided terrorist attacks, consideration should be given to surveilling communications, including those utilizing undersea cables, with supervision and auditing by democratic institutions.

・Key References

• Sherry Sontag and Christopher Drew, with Annette Lawrence Drew, Blind Man's Bluff: The Untold Story of American Submarine Espionage, Hutchinson, 1999.
• Barbara Tuchman, The Zimmermann Telegram: The Astounding Espionage Operation That Propelled America into the First World War, Random House, 2016.
• Motohiro Tsuchiya, Cybersecurity and International Politics, Chikura Shobo Publishers, 2015 (in Japanese).
• Daniel R. Headrick, The Invisible Weapon: Telecommunications and International Politics, 1851-1945, Oxford University Press, 2012.