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42:, a membership certificate or some kind of ticket to obtain some service, such as a cinema ticket or a public transport ticket, a digital credential is a proof of qualification, competence, or clearance that is attached to a person. Also, digital credentials prove something about their owner. Both types of credentials may contain personal information such as the person's name, birthplace, birthdate, and/or biometric information such as a picture or a finger print.
132:
credentials in the physical realm can be exemplified by forms of currency, bus and train tickets, and game-arcade tokens. These items lack personally identifiable information, allowing for their transfer between users without the issuers or relying parties being aware of such transactions. Organizations responsible for issuing credentials verify the authenticity of the information contained within them, which can be provided to verifying entities upon request.
213:
entity exists, capable of disclosing the actual identity of the signer and managing the addition or removal of users from the group, often through the issuance or revocation of group membership certificates. The anonymity, unlinkability, and anonymity revocation features provided by group signatures make them suitable for various privacy-sensitive applications, such as voting, bidding, anonymous payments, and anonymous credentials.
243:
that provides analogous functionality without sacrificing performance: an efficient batch issuing protocol capable of simultaneously issuing multiple unlinkable credentials. This mechanism can be combined with a privacy-preserving certificate refresh process, which generates a fresh unlinkable credential with the same attributes as a previously spent credential.
103:
only be utilised in transactions with authorised merchants. Anonymity is maintained for individuals as long as they ensure that a coin is spent only once. However, if an individual attempts to spend the same coin multiple times, their identity can be established, enabling the bank or relevant authority to take appropriate actions.
196:
further advanced digital credentials by introducing secret-key certificate-based credentials, enhancing Chaum's basic blind-signature system in both the discrete logarithm and strong RSA assumption settings. Brands credentials offer efficient algorithms and unconditional commercial security in terms
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Credentials, on the other hand, serve as tangible evidence of an individual's qualifications or attributes, acting as a validation of their capabilities. One notable example is the concept of E-Coins, which are exclusively assigned to individuals and are not transferable to others. These E-Coins can
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In a group signature scheme, members of a group can sign a message using their respective secret keys. The resulting signature can be verified by anyone possessing the common public key, without revealing any information about the signer other than their group membership. Typically, a group manager
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In contrast, the usage of credit cards, despite sharing a fundamental purpose with money, allows for the generation of detailed records pertaining to the cardholder. Consequently, credit cards are not considered protective of privacy. The primary advantage of money, in terms of privacy, is that its
242:
From an application perspective, the main advantage of
Camenisch et al.'s multi-show unlinkable credentials over the more efficient Brands credentials is the property of multi-show unlinkability. However, this property is primarily relevant in offline settings. Brands credentials offer a mechanism
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To explore the specific privacy-related characteristics of credentials, it is instructive to examine two types of credentials: physical money and credit cards. Both facilitate payment transactions effectively, although the extent and quality of information disclosed differ significantly. Money is
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possibilities for multi-show unlinkable showing protocols. WWhile blind signatures are highly relevant for electronic cash and single-show credentials, the cryptographic primitive known as group signature introduced new avenues for constructing privacy-enhancing protocols. Group signatures share
216:
Efficient constructions for group signatures were presented by
Ateniese, Camenisch, Joye, and Tsudik while the most efficient multi-show unlinkable anonymous credential systems]โwith the latter being a streamlined version of idemixโare based on similar principles. This is particularly true for
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safeguarded against counterfeiting through its physical properties. Furthermore, it reveals minimal information, with coins featuring an inherent value and year of minting, while banknotes incorporate a unique serial number to comply with traceability requirements for law enforcement purposes.
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represent a valuable expansion of anonymity. They afford users the ability to adopt different names when interacting with each organization. While pseudonyms enable organizations to establish associations with user accounts, they are unable to ascertain the true identities of their customers.
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include documents like passports, driving licenses, credit cards, health insurance cards, and club membership cards. These credentials bear the owner's name and possess certain validating features, such as signatures, PINs, or photographs, to prevent unauthorised usage. In contrast, anonymous
45:
Because of the still evolving, and sometimes conflicting, terminologies used in the fields of computer science, computer security, and cryptography, the term "digital credential" is used quite confusingly in these fields. Sometimes passwords or other means of authentication are referred to as
115:
The concept of anonymous digital credentials centres around the provision of cryptographic tokens to users, enabling them to demonstrate specific statements about themselves and their associations with public and private organizations while maintaining anonymity. This approach is viewed as a
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The shared characteristic of being tied to an individual forms the basis for the numerous similarities between digital cash and digital credentials. This commonality explains why these two concepts often exhibit overlapping features. In fact, it is worth noting that a significant majority of
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Credentials utilised within a national identification system are particularly relevant to privacy considerations. Such identification documents, including passports, driver's licenses, or other types of cards, typically contain essential personal information. In certain scenarios, it may be
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protocols as a novel cryptographic primitive. In such protocols, the signer remains oblivious to the message being signed, while the recipient obtains a signature without any knowledge of the signed message. Blind signatures serve as a crucial building block for various privacy-sensitive
270:(MOOCs) have a very direct bearing on our understanding of learning, recognition and levels as they pose a direct challenge to the status quo. It is useful to distinguish between three forms of online credentials: Test-based credentials, online badges, and online certificates.
257:
Online credentials for learning are digital credentials that are offered in place of traditional paper credentials for a skill or educational achievement. Directly linked to the accelerated development of internet communication technologies, the development of
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advantageous to selectively disclose only specific portions of the information contained within the identification document. For example, it might be desirable to reveal only the minimum age of an individual or the fact that they are qualified to drive a car.
165:
Nonetheless, through the utilisation of an anonymous credential, specific assertions concerning a user's relationship with one organization, under a pseudonym, can be verified by another organization that only recognizes the user under a different pseudonym.
224:. Proofs of knowledge based on the discrete logarithm problem for groups of known order and the special RSA problem for groups of hidden order form the foundation for most modern group signature and anonymous credential systems. Moreover, the
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is sometimes referred to as a pseudonym system. This nomenclature arises from the nature of the credentials within this system, which are acquired and presented to organizations under distinct pseudonyms that cannot be linked together.
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can be considered the first commercial application of multi-show anonymous digital credentials, although in this case, the credentials are associated with chips and computer platforms rather than individuals.
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applications, including anonymous payments, voting systems, and credentials. The original notion of an anonymous credential system was derived from the concept of blind signatures but relied on a
95:, has introduced a new set of challenges due to their susceptibility to replication. Consequently, digital cash protocols have been developed with additional measures to mitigate the issue of
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privacy-conscious alternative to the storage and utilization of extensive centralized user records, which can be linked together. Anonymous digital credentials are thus related to
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Anonymous credential systems have a close connection to the concept of untraceable or anonymous payments. David Chaum made significant contributions to this field by introducing
787:
Ateniese, Giuseppe; Camenisch, Jan; Joye, Marc; Tsudik, Gene (2000). "A practical and provably secure coalition-resistant group signature scheme". In
Bellare, Mihir (ed.).
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users can preserve their anonymity. However, real-world cash also possesses additional security and usability features that contribute to its widespread acceptance.
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are a form of digital credential that indicate an accomplishment, skill, quality or interest. Digital badges can be earned in a variety of learning environments.
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833:(2001). "An efficient system for non-transferable anonymous credentials with optional anonymity revocation". In Pfitzmann, Birgit (ed.).
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Another form of credentials that adds a new feature to anonymous credentials is multi-show unlinkability, which is realized through
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for the transfer of credentials, involving the translation from one pseudonym to another. Chaum's blind signature scheme, based on
1172:
1073:
Camenisch, Jan; Michels, Markus (1998). "A Group
Signature Scheme with Improved Efficiency". In Kazuo Ohta; Dingyi Pei (eds.).
252:
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credential systems that provide efficient means for implementing anonymous multi-show credentials with credential revocation.
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87:, in general, is not regarded as a form of qualification that is inherently linked to a specific individual, as the value of
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235:
225:
894:(2003). "A Signature Scheme with Efficient Protocols". In Cimato, Stelvio; Galdi, Clemente; Persiano, Giuseppe (eds.).
945:(2002). "Dynamic Accumulators and Application to Efficient Revocation of Anonymous Credentials". In Yung, Moti (ed.).
323:
338:
Level-setting and recognition of learning outcomes: The use of level descriptors in the twenty-first century
267:
680:(1983). "Blind signatures for untraceable payments". In Chaum, David; Rivest, Ronald L.; Sherman, Alan T (eds.).
535:
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471:
439:
407:
1140:
Level-setting and recognition of learning outcomes: The use of level descriptors in the twenty-first century
229:
903:
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59:
55:
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570:(October 1985). "Security without identification: transaction systems to make big brother obsolete".
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implementations of anonymous digital credentials also incorporate elements of digital cash systems.
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987:; Goldreich, Oded (1993). "On Defining Proofs of Knowledge". In Brickell, Ernest F (ed.).
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is perceived to reside independently. However, the emergence of digital assets, such as
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of privacy, along with additional features like a proof of non-membership blacklist.
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341:, 129-131, Keevey, James; Chakroun, Borhene, UNESCO. UNESCO.
35:
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1114:"Digital Credential Platform ๐ฏ ๐ณ๐ฎ๐ฐ๐๐ about ๐๐ฟ๐ฒ๐ฑ๐ฒ๐ป๐๐ถ๐ฎ๐น"
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58:) that is used for determining its access rights. On other occasions,
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The original system of anonymous credentials, initially proposed by
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problem, enabled the construction of anonymous credential systems.
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The introduction of pseudonyms is a useful extension to anonymity.
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67:
63:
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Chaum, David; van Heyst, Eugene (1991). "Group signatures". In
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Analogous to the physical world, personalised or non-anonymous
876:
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Rethinking public key infrastructures and digital certificates
369:
367:
699:
622:; Sahai, Amit; Wolf, Stefan (2000). "Pseudonym systems". In
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related credentials of
Camenisch et al. The introduction of
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similarities with Chaum's concept of credential systems.
529:"PRIME Whitepaper: privacy enhanced identity management"
497:"PRIME Whitepaper: privacy enhanced identity management"
465:"PRIME Whitepaper: privacy enhanced identity management"
433:"PRIME Whitepaper: privacy enhanced identity management"
401:"PRIME Whitepaper: privacy enhanced identity management"
99:, wherein a coin is used for multiple transactions.
62:
and associated key material such as those stored in
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360:. The Chronicle of Higher Education. 8 April 2012.
824:
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782:
780:
1031:"Efficient signature generation by smart cards"
331:work. Licensed under CC-BY-SA IGO 3.0 (
220:Both schemes are based on techniques for doing
1083:. Vol. 1514. Springer. pp. 160โ174.
955:. Vol. 2442. Springer. pp. 101โ120.
902:. Vol. 2576. Springer. pp. 268โ289.
797:. Vol. 1880. Springer. pp. 255โ270.
711:
709:
640:. Vol. 1758. Springer. pp. 184โ199.
34:. Just as a paper-based credential could be a
997:. Vol. 740. Springer. pp. 390โ420.
843:. Vol. 2045. Springer. pp. 93โ118.
755:. Vol. 547. Springer. pp. 257โ265.
8:
327: This article incorporates text from a
50:design, credentials are the properties of a
30:are the digital equivalent of paper-based
907:
873:"idemix- pseudonymity for e-transactions"
583:
1137:Keevy, James; Chakroun, Borhene (2015).
232:, is also based on the same techniques.
836:Advances in Cryptology โ EUROCRYPT 2001
349:
1076:Advances in Cryptology โ ASIACRYPT '98
748:Advances in Cryptology โ EUROCRYPT '91
374:Paolucci, Beatrice (9 December 2022).
534:. PRIME. 27 June 2007. Archived from
502:. PRIME. 27 June 2007. Archived from
470:. PRIME. 27 June 2007. Archived from
438:. PRIME. 27 June 2007. Archived from
406:. PRIME. 27 June 2007. Archived from
7:
948:Advances in Cryptology โ CRYPTO 2002
790:Advances in Cryptology โ CRYPTO 2000
688:'82. Plenum Press. pp. 199โ203.
70:#15 are referred to as credentials.
1146:. Paris, UNESCO. pp. 129โ131.
990:Advances in Cryptology โ CRYPTO '92
896:Security in Communication Networks
25:
1081:Lecture Notes in Computer Science
995:Lecture Notes in Computer Science
953:Lecture Notes in Computer Science
900:Lecture Notes in Computer Science
841:Lecture Notes in Computer Science
795:Lecture Notes in Computer Science
753:Lecture Notes in Computer Science
638:Lecture Notes in Computer Science
322:
228:, a protocol for authenticating
253:Online credentials for learning
247:Online credentials for learning
633:Selected Areas in Cryptography
296:Privacy enhancing technologies
1:
376:"The Future of Digital Money"
333:license statement/permission
286:Direct anonymous attestation
236:Direct anonymous attestation
226:direct anonymous attestation
268:massive open online courses
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716:Brands, Stefan A. (2000).
250:
572:Communications of the ACM
358:"A Future Full of Badges"
1089:10.1007/3-540-49649-1_14
1003:10.1007/3-540-48071-4_28
918:10.1007/3-540-36413-7_20
803:10.1007/3-540-44598-6_16
761:10.1007/3-540-46416-6_22
646:10.1007/3-540-46513-8_14
230:trusted platform modules
1173:Cryptographic protocols
961:10.1007/3-540-45708-9_5
849:10.1007/3-540-44987-6_7
335:). Text taken from
54:(such as its effective
682:Advances in Cryptology
311:Verifiable credentials
1039:Journal of Cryptology
1027:Schnorr, Claus-Peter
264:electronic passports
18:Anonymous credential
291:Electronic commerce
222:proofs of knowledge
186:signatures and the
28:Digital credentials
1112:certifyMe.online.
1052:10.1007/BF00196725
628:Adams, Carlisle M.
188:discrete logarithm
1153:978-92-3-100138-3
1098:978-3-540-65109-3
1012:978-3-540-57340-1
970:978-3-540-44050-5
943:Lysyanskaya, Anna
927:978-3-540-00420-2
892:Lysyanskaya, Anna
858:978-3-540-42070-5
831:Lysyanskaya, Anna
812:978-3-540-67907-3
770:978-3-540-54620-7
727:978-0-262-02491-4
655:978-3-540-67185-5
620:Rivest, Ronald L.
616:Lysyanskaya, Anna
594:10.1145/4372.4373
578:(10): 1030โ1044.
541:on 17 August 2007
509:on 17 August 2007
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413:on 17 August 2007
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700:"Credentica"
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568:Chaum, David
543:. Retrieved
536:the original
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511:. Retrieved
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60:certificates
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306:Token money
281:Cypherpunks
154:David Chaum
129:credentials
89:token money
32:credentials
1123:2021-11-01
345:References
162:Pseudonyms
148:Pseudonyms
904:CiteSeerX
580:CiteSeerX
122:anonymity
111:Anonymous
1167:Category
1060:10976365
630:(eds.).
602:15340054
380:IBM Blog
274:See also
66:#12 and
36:passport
745:(ed.).
545:28 June
513:28 June
481:28 June
449:28 June
417:28 June
318:Sources
169:History
118:privacy
52:process
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385:24 May
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