SAML 2.0 introduced a number of features not available in previous versions of the specification, including:

Pseudonyms – SAML 2.0 defines how an opaque pseudo-random identifier with no discenible correspondence with meaningful identifiers (for example, emails or account names) can be used between providers to represent principals. Pseudonyms are a key privacy-enabling technology because they inhibit collusion between multiple providers (as would be possible with a global identifier such as an email address).

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