Jnc: Explains the basic idea, and common uses

2026-09-23T10:24:31Z

Explains the basic idea, and common uses

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A '''public key''' [[cryptosystem]] is one in which ''different'' [[key]]s are used to ''encrypt'' and ''decrypt'' any item. The keys in the pair are termed the 'public' key, and the 'private' key (from their now-common use, in which one key of the pair is widely distributed, and the other is tightly held).

They are now widely used on the [[Internet]], to [[sign]] information (e.g. in the [[Domain Name System]]), and in other ways (e.g. to securely exchange keys for use with another cryptosystem).

==History==

The concept of public key cryptography was first invented by James Ellis, then of UK's Government Communications Headquarters, in 1970. He had come up with only the basic idea; another person there, Clifford Cocks, came up with a cryptosystem which implemented it.

However, their ideas were kept classified - a step which did no good, as in 1976, the basic idea was independently rediscovered by Whitfield Diffie and Martin Hellman (who devised a secure method, usable by two remote entities, for creating key pairs, 'at a distance'). Shortly thereafter, in 1977, Ron Rivest, Adi Shamir and Leonard Adleman devised a cryptosystem which implemented the public key idea.

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[[Category: Security]]

Public key - Revision history

Jnc: Explains the basic idea, and common uses