Alice and Bob

The names Alice and Bob are commonly used placeholders for archetypal characters in fields such as cryptography and physics. Placeholder names are words that can refer to objects or people whose names are either irrelevant or unknown in the context in which it is being discussed Cryptography (or cryptology; from Greek grc κρυπτός kryptos, "hidden secret" and grc γράφω gráphō, "I write" Physics (Greek Physis - φύσις in everyday terms is the Science of Matter and its motion. The names are used for convenience, since explanations such as "Person A wants to send a message to person B" can be difficult to follow in complex systems involving many steps. Following the alphabet, the specific names have evolved into common parlance within these fields — helping technical topics to be explained in a more understandable fashion.

In cryptography and computer security, there are a number of widely-used names for the participants in discussions and presentations about various protocols. Cryptography (or cryptology; from Greek grc κρυπτός kryptos, "hidden secret" and grc γράφω gráphō, "I write" This article describes how security can be achieved through design and engineering A security protocol ( cryptographic protocol or encryption protocol) is an abstract or concrete protocol that performs a security -related function The names are conventional, somewhat self-suggestive, sometimes humorous, and effectively act as metasyntactic variables. A metasyntactic variable (ˌmɛtəsɪnˈtæktɪk ˈvɛəriəbl is a Placeholder name or an alias term commonly used to denote the subject matter under discussion

In typical implementations of these protocols, it is understood that the actions attributed to characters such as Alice or Bob would not normally be carried out by human parties directly, but rather by a trusted automated agent (such as a computer program) on their behalf.

1 List of characters
2 See also
3 References
4 External links

List of characters

This list is drawn mostly from the book Applied Cryptography by Bruce Schneier. Bruce Schneier (born 15 January 1963) is an American Cryptographer, Computer security specialist and Writer. Alice and Bob are archetypes in cryptography; Eve is also common. Names further down the alphabet are less common.

Alice and Bob. Generally, Alice wants to send a message to Bob. These names were used by Ron Rivest in the 1978 Communications of the ACM article presenting the RSA cryptosystem, and in A Method for Obtaining Digital Signatures and Public-Key Cryptosystems published April 4, 1977, revised September 1, 1977 as technical Memo LCS/TM82. Ronald Linn Rivest (born 1947, Schenectady, New York) is a cryptographer. Year 1978 ( MCMLXXVIII) was a Common year starting on Sunday (link displays the 1978 Gregorian calendar) The Association for Computing Machinery, or ACM, was founded in 1947 as the world's first scientific and educational Computing society In Cryptography, RSA is an Algorithm for Public-key cryptography. Also 1977 (album by Ash. Year 1977 ( MCMLXXVII) was a Common year starting on Saturday (link displays Also 1977 (album by Ash. Year 1977 ( MCMLXXVII) was a Common year starting on Saturday (link displays Rivest denies that these names have any relation to the 1969 movie Bob & Carol & Ted & Alice as occasionally suggested by others. Year 1969 ( MCMLXIX) was a Common year starting on Wednesday (link will display full calendar of the Gregorian calendar. This article is about the 1969 film For the 1973 television series based on this film see Bob & Carol & Ted & Alice (TV series.
Carol or Charlie, as a third participant in communications.
Dave, a fourth participant, and so on alphabetically.
Eve, an eavesdropper, is usually a passive attacker. While she can listen in on messages between Alice and Bob, she cannot modify them. In quantum cryptography, Eve may also represent the environment. Quantum cryptography, or quantum key distribution (QKD uses Quantum mechanics to guarantee secure communication
Isaac, an Internet Service Provider (ISP). An Internet service provider ( ISP, also called Internet access provider or IAP) is a company which primarily offers their customers access to the Internet
Ivan, an issuer (as in financial cryptography).
Justin, from the justice system.
Mallory, a malicious attacker; unlike Eve, Mallory can modify messages, substitute her own messages, replay old messages, and so on. The problem of securing a system against Mallory is much greater than against Eve. The names Marvin and Mallet can also be used for this role.
Matilda, a merchant (as in e-commerce or financial cryptography).
Oscar, an opponent, is usually taken as equivalent to Mallory. In Cryptography, an adversary (rarely opponent, enemy) is a malicious entity whose aim is to prevent the users of the Cryptosystem from achieving
Pat or Peggy, a prover, and Victor, a verifier, often must interact in some way to show that the intended transaction has actually taken place. They are often found in zero-knowledge proofs. In Cryptography, a zero-knowledge proof or zero-knowledge protocol is an interactive method for one party to prove to another that a (usually mathematical statement Another name pair sometimes used is Pat and Vanna (after the host and hostess on the Wheel of Fortune television show). Pat Sajak (born Patrick Leonard Sajdak on October 26, 1946) is a Television personality, former weatherman and a former Talk Vanna White (born February 18 1957 is an American Television personality best known as puzzle-board presenter and co-host on the long-running Game show
Plod, a law enforcement officer (also "Officer Plod") from the children's fictional character Mr. Plod, in the Noddy books by Enid Blyton. Mr Plod (born 17 July, 1954) is a Fictional character in the Noddy children's series by Enid Blyton. Noddy is a character created by British Children's author Enid Blyton, originally published between 1949 and 1963 Enid Mary Blyton ( August 11 1897 &ndash November 28 1968) was a British children's writer.
Steve, sometimes used in reference to Steganography. Steganography is the art and science of writing hidden messages in such a way that no one apart from the sender and intended recipient even realizes there is a hidden message
Trent, a trusted arbitrator, is some kind of neutral third party, whose exact role varies with the protocol under discussion.
Trudy, an intruder: another alternative to Mallory.
Walter, a warden, may be needed to guard Alice and Bob in some respect, depending on the protocol being discussed.
Zoe, often the last party to be involved in a cryptographic protocol. A security protocol ( cryptographic protocol or encryption protocol) is an abstract or concrete protocol that performs a security -related function

Although an interactive proof system is not quite a cryptographic protocol, it is sufficiently related to mention the 'cast of characters' its literature features:

Arthur and Merlin: In interactive proof systems, the prover has unbounded computational ability and is hence associated with Merlin, the powerful wizard. In Computational complexity theory, an interactive proof system is an Abstract machine that models Computation as the exchange of messages between two parties The Multi-Element Radio Linked Interferometer Network ( MERLIN) is an Interferometer array of Radio telescopes spread across England and the A magician, wizard, sorcerer or a person known under one of many other possible terms in fiction is someone who uses or practices magic He claims the truth of a statement, and Arthur, the wise king, questions him to verify the claim. King Arthur is a legendary British leader who according to medieval histories and romances, led the defence of Britain against the Saxon invaders These two characters also give the name for two complexity classes, namely MA and AM. In Computational complexity theory, a complexity class is a set of problems of related complexity In Computational complexity theory, an Arthur-Merlin protocol is an Interactive proof system in which the verifier's coin tosses are constrained to be public (i In Computational complexity theory, an Arthur-Merlin protocol is an Interactive proof system in which the verifier's coin tosses are constrained to be public (i

References

C. A metasyntactic variable (ˌmɛtəsɪnˈtæktɪk ˈvɛəriəbl is a Placeholder name or an alias term commonly used to denote the subject matter under discussion Dave and Sue are two fictional Radio listeners Descriptions of the characters created by the BBC, are given to all their local radio presenters as representative H. Lindsey, Regulation of Investigatory Powers Bill: Some Scenarios, 2000, [1].

External links

A quantum computer is a device for Computation that makes direct use of distinctively Quantum mechanical Phenomena, such as superposition

Dictionary

-proper noun

(cryptography) Two people wishing to communicate securely with each other, Alice sending Bob information.

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