3.5.2 Overview of Sighchain Types
Zoom devices, users, and accounts are each internally identified by unique immutable identifiers called deviceID, userID, and accountID respectively. The deviceID is generated randomly for each new device, while the userID and accountID are assigned by the server.
Each device, user, and account is also associated with more user-friendly (but mutable) identifiers: respectively, device names, email addresses, and ADNs.
Representing these different components and their relationships requires different types of sighchains:
User sighchains store, for each userID, information related to that user’s identity, such as the user's email address, accountID, and the set of their devices and their trust relationships.
Email sighchains store, for each email address, the associated userID.
Account sighchains store, for each accountID, both the ADN and identity provider associated with the account.
ADN sighchains keep track of, for each domain name, the accountID to which the domain is associated.
Membership sighchains keep track of, for each accountID, the userIDs within the account count.
Note that some of the information stored on these sighchains is redundant; for example, a mapping between an email and the corresponding userID is recorded both in a user sighchain and in an email sighchain. This is necessary so that the server cannot claim that two separate userIDs are associated with the same email address at the same time. Accordingly, some operations will cause multiple chains to be updated at the same time.
As detailed earlier, every Zoom user is part of an account. As potential optimizations, if this account only has a single user and doesn’t have an ADN, then that user’s sighchain might not mention their accountID, and there would be no corresponding account or membership sighchains until the account either gets another user or an ADN.
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