In operating system design, credentials are the properties of a process (such as its effective UID) that is used for determining its access rights.
Consequently, digital cash protocols have been developed with additional measures to mitigate the issue of double spending, wherein a coin is used for multiple transactions.
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.
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 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.
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.
[5] 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.
Such identification documents, including passports, driver's licenses, or other types of cards, typically contain essential personal information.
[9] 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.
While pseudonyms enable organizations to establish associations with user accounts, they are unable to ascertain the true identities of their customers.
[10] David Chaum made significant contributions to this field by introducing blind signature protocols as a novel cryptographic primitive.
Blind signatures serve as a crucial building block for various privacy-sensitive applications, including anonymous payments, voting systems, and credentials.
Brands credentials offer efficient algorithms and unconditional commercial security in terms of privacy,[11] along with additional features like a proof of non-membership blacklist.
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.
Text taken from Level-setting and recognition of learning outcomes: The use of level descriptors in the twenty-first century, 129-131, Keevey, James; Chakroun, Borhene, UNESCO.