Concepts
Public Key Cryptography
Also Known As Asymmetric cryptography
Technique
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Public key cryptography, or asymmetric cryptography, is the field of cryptographic systems that use pairs of related keys, one public and one private, so that strangers can exchange secrets without first sharing a key. Whitfield Diffie and Martin Hellman published the idea in 1976, but Britain's GCHQ had reached it in secret years earlier: James H. Ellis conceived non-secret encryption in 1970 and Clifford Cocks implemented what became the RSA algorithm in 1973, a double discovery this atlas records as the field's own character.
Facts
Disputed
Origin Year1976 is the public origin, the Diffie and Hellman publication; GCHQ's classified work reached the same ideas earlier, with James H. Ellis conceiving non-secret encryption in 1970 and Clifford Cocks implementing what became RSA in 1973. Which date counts as the origin depends on whether secret work counts. Core PrincipleTwo mathematically related keys, one published and one kept private, let anyone encrypt a message that only the private key holder can read. 1 Cross-Tradition Connections
Sources
1. Wikipedia: Public Key Cryptography
Wikimedia FoundationDescription and discovery sectionsQuote, Description and discovery sections
Public-key cryptography, or asymmetric cryptography, is the field of cryptographic systems that use pairs of related keys.
1. Wikipedia: Public Key Cryptography
Wikimedia FoundationPublic discovery and Classified discovery sectionsQuote, Public discovery and Classified discovery sections
In 1970, James H. Ellis, a British cryptographer at the UK Government Communications Headquarters (GCHQ), conceived of the possibility of 'non-secret encryption'.
1. Wikipedia: Public Key Cryptography
Wikimedia FoundationIn Field: Information Security, Lead sectionQuote, In Field: Information Security, Lead section
Public-key cryptography, or asymmetric cryptography, is the field of cryptographic systems that use pairs of related keys.
Wikipedia: Whitfield Diffie
Wikimedia FoundationInvented By: Whitfield Diffie, Public discovery (public-key-cryptography article)Quote, Invented By: Whitfield Diffie, Public discovery (public-key-cryptography article)
In 1976, an asymmetric key cryptosystem was published by Whitfield Diffie and Martin Hellman who, influenced by Ralph Merkle's work on public key distribution, disclosed a method of public key agreement.
Open Questions (1 open question)
Can large integers be factored efficiently on a classical computer?
When the numbers are sufficiently large, no efficient non quantum integer factorization algorithm is known, yet it has not been proven that no such algorithm exists. The presumed difficulty of this problem is what the security of RSA public key encryption and signatures rests on, so the gap between no algorithm known and no algorithm possible carries the weight of most of the world's encrypted traffic. Peter Shor showed in 1994 that a quantum computer could factor in polynomial time, which sharpens rather than settles the classical question.
What would resolve this An efficient classical factoring algorithm, which would break RSA, or a proof that none exists, which would put its security on solid ground; large scale quantum computers would change the practical stakes either way.
Computational number theory, CryptographyWikipedia: Integer Factorization
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