Editing Alice and Bob (section)

==Cast of characters==

===Cryptographic systems===
{{More citations needed section|date=May 2023}} 
The most common characters are Alice and Bob. Eve, Mallory, and Trent are also common names, and have fairly well-established "personalities" (or functions). The names often use alliterative mnemonics (for example, Eve, "eavesdropper"; Mallory, "malicious") where different players have different motives. Other names are much less common and more flexible in use. Sometimes the genders are alternated: Alice, Bob, Carol, Dave, Eve, etc.<ref>{{cite journal|last1=Xue|first1=Peng|last2=Wang|first2=Kunkun|last3=Wang|first3=Xiaoping|title=Efficient multiuser quantum cryptography network based on entanglement|journal=Scientific Reports|volume=7|issue=1|year=2017|page=45928|issn=2045-2322|doi=10.1038/srep45928|pmid=28374854|pmc=5379677|bibcode=2017NatSR...745928X|doi-access=free}} An example from quantum cryptography with Alice, Bob, Carol, and David.</ref>

{| class="wikitable"
|-
| ''Alice'' and ''Bob''
| The original, generic characters. Generally, Alice and Bob want to exchange a message or cryptographic key.
|-
| ''Carol'', ''Carlos'' or ''Charlie''
| A generic third participant.
|-
| ''Chuck'' or ''Chad''
| A third participant, usually of malicious intent.<ref>{{cite book |last=Tanenbaum |first=Andrew S. |title=Distributed Systems: Principles and Paradigms |isbn=978-0-13-239227-3 | publisher=[[Pearson Prentice Hall]] |year=2007 |url=https://books.google.com/books?id=DL8ZAQAAIAAJ |page=171;399&ndash;402 }}</ref>
|-
| ''Craig''
| A ''[[password cracking|password cracker]],'' often encountered in situations with stored passwords.
|-
| ''Dan'', ''Dave'' or ''David'' || A generic fourth participant.
|-
| ''Erin''
| A generic fifth participant, but rarely used, as "E" is usually reserved for Eve.
|-
| {{Anchor|Eve}}''Eve'' or ''Yves''
| An ''[[Eavesdropping|eavesdropper]]'', who is usually a passive attacker. While they can listen in on messages between Alice and Bob, they cannot modify them. In [[quantum cryptography]], Eve may also represent the ''environment''.{{clarify|date=November 2018}}
|-
| ''Faythe''
| A ''trusted [[Adviser|advisor]]'', courier or intermediary. Faythe is used infrequently, and is associated with ''faith'' and ''faithfulness''. Faythe may be a repository of key service or courier of shared secrets.{{citation needed|date=March 2016}}
|-
| ''Frank''
| A generic sixth participant.
|-
| ''Grace''
| A ''government representative''. For example, Grace may try to force Alice or Bob to implement backdoors in their protocols. Grace may also deliberately weaken standards.<ref>{{cite arXiv |eprint=2003.11511 |last1=Cho |first1=Hyunghoon |last2=Ippolito |first2=Daphne |author3=Yun William Yu |title=Contact Tracing Mobile Apps for COVID-19: Privacy Considerations and Related Trade-offs |year=2020 |class=cs.CR }}</ref>
|-
| ''Heidi''
| A ''mischievous designer'' for cryptographic standards, but rarely used.<ref>{{Cite book |last1=Fried |first1=Joshua |last2=Gaudry |first2=Pierrick |last3=Heninger |first3=Nadia |author3-link=Nadia Heninger |last4=Thomé |first4=Emmanuel |title=Advances in Cryptology – EUROCRYPT 2017 |chapter=A Kilobit Hidden SNFS Discrete Logarithm Computation |url=https://eprint.iacr.org/2016/961.pdf |publisher=University of Pennsylvania and INRIA, CNRS, University of Lorraine |series=Lecture Notes in Computer Science |date=2017 |volume=10,210 |pages=202–231 |doi=10.1007/978-3-319-56620-7_8 |arxiv=1610.02874 |isbn=978-3-319-56619-1 |s2cid=12341745 |access-date=2016-10-12}}</ref>
|-
| ''Ivan''
| An ''issuer'', mentioned first by Ian Grigg in the context of [[Ricardian contract]]s.<ref>{{Cite web|last=Grigg|first=Ian|title=Ivan The Honourable|url=http://iang.org/rants/ivan_the_honourable.html| website=iang.org | date=2002-11-24}}</ref>
|-
| ''Judy''
| A ''judge'' who may be called upon to resolve a potential dispute between participants. See [[Judge Judy]].
|-
| {{Anchor|Mallory}}{{Anchor|Mallet}}{{Anchor|Trudy}}''Mallory''<ref name="Schneier1996" /><ref>{{cite journal |last=Szabo |first=Nick |author-link=Nick Szabo |date=September 1997 |title=Formalizing and Securing Relationships on Public Networks |url=http://firstmonday.org/ojs/index.php/fm/article/view/548/469 |journal=First Monday|volume=2 |issue=9 |doi=10.5210/fm.v2i9.548|s2cid=33773111 |doi-access=free }}</ref><ref>{{citation |last=Schneier|first=Bruce |author-link=Bruce Schneier |title=Who are Alice & Bob? |date=2010-09-23 |url=https://www.youtube.com/watch?v=BuUSi_QvFLY  |archive-url=https://ghostarchive.org/varchive/youtube/20211222/BuUSi_QvFLY |archive-date=2021-12-22 |url-status=live|access-date=2017-05-02 |website=YouTube}}{{cbignore}}</ref> or (less commonly) ''Mallet''<ref name=Schneier1994/><ref name=Perkins2000/><ref name=LaMacchia2002/><ref name=Dolev2009/> or ''Darth''<ref name=Stallings1998/>
| A ''malicious attacker''. Associated with Trudy, an ''intruder''. Unlike the passive Eve, Mallory is an active attacker (often used in [[man-in-the-middle attack]]s), who can modify messages, substitute messages, or replay old messages. The difficulty of securing a system against a Mallory is much greater than against an Eve.
|-
| ''Michael'' or ''Mike''
| Used as an alternative to the eavesdropper Eve, from ''[[microphone]]''.
|-
| ''Niaj''
| Used as an alternative to the eavesdropper Eve in several South Asian nations.<ref>{{Cite web|title=A Collaborative Access Control Framework for Online Social Networks|url=http://raulpardo.net/papers/JLAMP2020.pdf}}</ref>
|-
| ''Olivia''
| An ''[[Oracle machine|oracle]]'', who responds to queries from other participants. Olivia often acts as a "[[black box]]" with some concealed state or information, or as a [[random oracle]].
|-
| ''Oscar''
| An ''opponent'', similar to Mallory, but not necessarily malicious.
|-
| ''Peggy'' or ''Pat''
| A ''prover'', who interacts with the ''verifier'' to show that the intended transaction has actually taken place. Peggy is often found in [[zero-knowledge proof]]s. 
|-
| ''Rupert''
| A ''repudiator'' who appears for interactions that desire [[non-repudiation]].
|-
|-
| ''Sybil''
| A ''[[pseudonym]]ous attacker'', who usually uses a large number of identities. For example, Sybil may attempt to subvert a [[reputation system]]. See [[Sybil attack]]. 
|-
| ''Trent'' or ''Ted''
| A ''trusted [[arbitral tribunal|arbitrator]]'', who acts as a [[trusted third party|neutral third party]].
|-
| ''Trudy''
| An ''intruder''.
|-
| ''Victor''<ref name="Schneier1996" /> or ''Vanna''<ref>{{cite journal |year=1992 |title=Algebraic Methods for Interactive Proof Systems |journal=Journal of the ACM |volume=39 |issue=4 |pages=859–868 |doi=10.1145/146585.146605 |author-link=Carsten Lund |first=Carsten |last=Lund |display-authors=etal |citeseerx=10.1.1.41.9477|s2cid=207170996 }}</ref>
| ''A verifier'', who requires proof from the ''prover''.
|-
| ''Walter''
| A ''[[prison warden|warden]]'', who may guard Alice and Bob.
|-
| ''Wendy''
| A ''[[whistleblower]]'', who is an insider with privileged access capable of divulging information.
|}

===Interactive proof systems===

For [[interactive proof system]]s there are other characters:
{| class="wikitable"
|-
| ''Arthur'' and ''Merlin''
| Merlin provides answers, and Arthur asks questions.<ref>{{cite journal |last1=Babai |first1=László |last2=Moran |first2=Shlomo |title=Arthur-Merlin games: A randomized proof system, and a hierarchy of complexity classes |journal=[[Journal of Computer and System Sciences]] |date=April 1988 |volume=36 |issue=2 |pages=254–276 |doi=10.1016/0022-0000(88)90028-1 |doi-access=free }}</ref> Merlin has unbounded computational ability (like the wizard [[Merlin (wizard)|Merlin]]). In interactive proof systems, Merlin claims the truth of a statement, and Arthur (like [[King Arthur]]), questions him to verify the claim.
|-
| ''Paul'' and ''Carole''
| Paul asks questions, and Carole provides answers. In the solution of the [[Twenty Questions]] problem,<ref>{{citation |doi=10.1017/S0963548300000080 |last1=Spencer |first1=Joel |author1-link=Joel Spencer |last2=Winkler |first2=Peter |author2-link=Peter Winkler |title=Three Thresholds for a Liar |url=http://math.dartmouth.edu/~pw/papers/3thresh.ps |journal=Combinatorics, Probability and Computing |year=1992 |volume=1 |issue=1 |pages=81–93|s2cid=45707043 }}</ref> Paul (standing in for [[Paul Erdős]]) asked questions and Carole (an [[anagram]] of "[[oracle]]") answered them. Paul and Carole were also used in [[combinatorial game theory|combinatorial games]], in the roles of pusher and chooser.<ref>{{cite book |last=Muthukrishnan |first=S. |author-link=S. Muthukrishnan (computer scientist) |title=Data Streams: Algorithms and Applications |isbn=978-1-933019-14-7 |publisher=Now Publishers |year=2005 |url=http://algo.research.googlepages.com/eight.ps |page=3 }}{{Dead link|date=August 2023 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>
|-
| ''Arthur'' and ''Bertha''
| Arthur is the "left", "black", or "vertical" player, and Bertha is the "right", "white", or "horizontal" player in a [[combinatorial game theory|combinatorial game]]. Additionally, Arthur, given the same outcome, prefers a game to take the fewest moves, while Bertha prefers a game to take the most moves.<ref>{{Cite book |title=On Numbers and Games |last=Conway |first=John Horton |publisher=CRC Press |year = 2000 |isbn=9781568811277 |pages=71, 175, 176}}</ref>
|}

=== Physics ===
The names Alice and Bob are often used to name the participants in thought experiments in physics.<ref>{{Cite web |url=http://physicsworld.com/cws/article/news/2013/apr/16/alice-and-bob-communicate-without-transferring-a-single-photon|title=Alice and Bob communicate without transferring a single photon |website=physicsworld.com |date=16 April 2013 |language=en-GB |access-date=2017-06-19}}</ref><ref>{{Cite journal |last1=Frazier |first1=Matthew |last2=Taddese |first2=Biniyam |last3=Antonsen |first3=Thomas |last4=Anlage |first4=Steven M. |date=2013-02-07 |title=Nonlinear Time Reversal in a Wave Chaotic System |journal=Physical Review Letters |language=en-US |volume=110 |issue=6 |pages=063902 |doi=10.1103/physrevlett.110.063902 |pmid=23432243 |arxiv=1207.1667 |bibcode=2013PhRvL.110f3902F|s2cid=35907279 }}</ref> More alphabetical names, usually of alternating gender, are used as required, e.g. "Alice and Bob (and Carol and Dick and Eve)".<ref>{{Cite web |url=http://www.lassp.cornell.edu/lassp_data/master.pdf |title=209: Notes on Special Relativity |date=5 March 2000 |first=N. |last=David Mermin |author-link=N. David Mermin}} An example with several names.</ref>

In experiments involving robotic systems, the terms "Alice Robot" and "Bob Robot" refer to mobile platforms responsible for transmitting quantum information and receiving it with quantum detectors, respectively, within the context of the field of [[quantum robotics]].<ref>Farbod Khoshnoud, Lucas Lamata, Clarence W. De Silva, Marco B. Quadrelli, [https://arxiv.org/ftp/arxiv/papers/2007/2007.15249.pdf Quantum Teleportation for Control of Dynamic Systems and Autonomy], [https://www.actapress.com/PaperInfo.aspx?paperId=47550 Journal of Mechatronic Systems and Control, Volume 49, Issue 3, pp. 124-131, 2021].</ref><ref>{{cite journal |last1=Lamata |first1=Lucas |last2=Quadrelli |first2=Marco B. |last3=de Silva |first3=Clarence W. |last4=Kumar |first4=Prem |last5=Kanter |first5=Gregory S. |last6=Ghazinejad |first6=Maziar |last7=Khoshnoud |first7=Farbod |title=Quantum Mechatronics |journal=Electronics |date=12 October 2021 |volume=10 |issue=20 |pages=2483 |doi=10.3390/electronics10202483 |doi-access=free }}</ref><ref> Farbod Khoshnoud, Maziar Ghazinejad, Automated quantum entanglement and cryptography for networks of robotic systems, IEEE/ASME International Conference on Mechatronic and Embedded Systems and Applications (MESA), IDETC-CIE 2021, Virtual Conference: August 17 – 20, DETC2021-71653, 2021.</ref><ref>{{cite conference | last1=Khoshnoud | first1=Farbod | last2=Aiello | first2=Clarice | last3=Quadrelli | first3=Bruno | last4=Ghazinejad | first4=Maziar | last5=De Silva | first5=Clarence | last6=Khoshnoud | first6=Farbod | last7=Bahr | first7=Behnam | last8=Lamata | first8=Lucas | title=Modernizing Mechatronics course with Quantum Engineering | publisher=ASEE Conferences | date=23 April 2021 | doi=10.18260/1-2--38241 |url=https://peer.asee.org/38241|conference=2021 ASEE Pacific Southwest Conference - "Pushing Past Pandemic Pedagogy: Learning from Disruption"| doi-access=free }} [https://peer.asee.org/modernizing-mechatronics-course-with-quantum-engineering.pdf PDF]</ref><ref>{{cite journal |last1=Khoshnoud |first1=Farbod |last2=Esat |first2=Ibrahim I. |last3=de Silva |first3=Clarence W. |last4=Quadrelli |first4=Marco B. |title=Quantum Network of Cooperative Unmanned Autonomous Systems |journal=Unmanned Systems |date=April 2019 |volume=07 |issue=2 |pages=137–145 |doi=10.1142/S2301385019500055 |s2cid=149842737 |url=https://www.worldscientific.com/doi/abs/10.1142/S2301385019500055 |access-date=7 September 2023 |language=en |issn=2301-3850}}</ref><ref>Farbod Khoshnoud, Marco B. Quadrelli, Enrique Galvez, Clarence W. de Silva, Shayan Javaherian, B. Bahr, M. Ghazinejad, A. S. Eddin, M. El-Hadedy, Quantum Brain-Computer Interface, ASEE PSW, 2023, in press.</ref>