Public key cryptography is widely used to secure online transactions. The maths behind the technology was invented by UK Government Communications Headquarters scientists in the late 1960s and early 1970s.
The discovery was kept secret to avoid revealing how closely Government Communications Headquarters (GCHQ) was working with the US National Security Agency (NSA) at the time. The breakthrough by GCHQ scientists James Ellis, Clifford Cocks and Matthew Williamson only came to light in 1997, when their work was declassified.

In public key cryptography, data is encrypted using a widely distributed public key, and can be decrypted using a private key. GCHQ mathematician Clifford Cocks, who invented the practical method of public key cryptography in 1973, and Ralph Benjamin, who was GCHQ's chief scientist from 1971 to 1982, told ZDNet UK about their pioneering work.

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