Government Communications Headquarters - GCHQ

Government Communications Headquarters, commonly known as GCHQ, is an intelligence and security organisation responsible for providing signals intelligence (SIGINT) and information assurance to the government and armed forces of the United Kingdom. Based in "The Doughnut" in the suburbs of Cheltenham, GCHQ is the responsibility of the country's Secretary of State for Foreign and Commonwealth Affairs, but it is not a part of the Foreign Office and its Director ranks as a Permanent Secretary.

GCHQ was originally established after the First World War as the Government Code and Cypher School (GC&CS) and was known under that name until 1946. During the Second World War it was located at Bletchley Park, where it was responsible for breaking the German Enigma codes. There are two main components of the GCHQ, the Composite Signals Organisation (CSO), which is responsible for gathering information, and the National Cyber Security Centre (NCSC), which is responsible for securing the UK's own communications. The Joint Technical Language Service (JTLS) is a small department and cross-government resource responsible for mainly technical language support and translation and interpreting services across government departments. It is co-located with GCHQ for administrative purposes.

In 2013, GCHQ received considerable media attention when the former National Security Agency contractor Edward Snowden revealed that the agency was in the process of collecting all online and telephone data in the UK via the Tempora programme. Snowden's revelations began a spate of ongoing disclosures of global surveillance. The Guardian newspaper was then forced to destroy all incriminating files given to them by Snowden because of the threats of lawsuits from the UK Government.

Security Mission

As well as a mission to gather intelligence, GCHQ has for a long-time had a corresponding mission to assist in the protection of the British government's own communications. When the Government Code and Cypher School (GC&CS) was created in 1919, its overt task was providing security advice. GC&CS's Security section was located in Mansfield College, Oxford during the Second World War.

In April 1946, GC&CS became GCHQ, and the now GCHQ Security section moved from Oxford to join the rest of the organisation at Eastcote later that year.

From 1952 to 1954, the intelligence mission of GCHQ relocated to Cheltenham; the Security section remained at Eastcote, and in March 1954 became a separate, independent organisation: the London Communications Security Agency (LCSA), which in 1958 was renamed to the London Communications-Electronic Security Agency (LCESA).

In April 1965, GPO and MOD units merged with LCESA to become the Communications-Electronic Security Department (CESD).

In October 1969, CESD was merged into GCHQ and becoming Communications-Electronic Security Group (CESG).

In 1977 CESG relocated from Eastcote to Cheltenham.

CESG continued as the UK National Technical Authority for information assurance, including cryptography. CESG did not manufacture security equipment, but worked with industry to ensure the availability of suitable products and services, while GCHQ itself funded research into such areas, for example to the Centre for Quantum Computation at Oxford University and the Heilbronn Institute for Mathematical Research at the University of Bristol.

In the 21st century, CESG ran a number of assurance schemes such as CHECK, CLAS, Commercial Product Assurance (CPA) and CESG Assisted Products Service (CAPS).

Public key encryption
In late 1969 the concept for public-key encryption was developed and proven by James H. Ellis, who had worked for CESG (and before it, CESD) since 1965. Ellis lacked the number theory expertise necessary to build a workable system. Subsequently, a feasible implementation scheme via an asymmetric key algorithm was invented by another staff member Clifford Cocks, a mathematics graduate. This fact was kept secret until 1997.

In 2016, the National Cyber Security Centre was established under GCHQ but located in London, as the UK's authority on cybersecurity. It absorbed and replaced CESG as well as activities that had previously existed outside GCHQ: the Centre for Cyber Assessment (CCA), Computer Emergency Response Team UK (CERT UK) and the cyber-related responsibilities of the Centre for the Protection of National Infrastructure (CPNI).

International Relationships

GCHQ operates in partnership with equivalent agencies worldwide in a number of bi-lateral and multi-lateral relationships. The principal of these is with the United States (National Security Agency), Canada (Communications Security Establishment), Australia (Australian Signals Directorate) and New Zealand (Government Communications Security Bureau), known as the FIVE EYES, through the mechanism of the UK-US Security Agreement, a broad intelligence-sharing agreement encompassing a range of intelligence collection methods. Relationships are alleged to include shared collection methods, such as the system described in the popular media as ECHELON, as well as analysed product.

Stations and Former Stations

Former Stations

  • GCHQ Brora, Sutherland
  • GCHQ Cheadle, Staffordshire
  • GCHQ Culmhead, Somerset
  • GCHQ Hawklaw, Fife
  • GCHQ Hong Kong