This is
PairwiseOidcRegisteredServiceUsernameAttributeProvider.
This provides a different sub value to each Client, so as not to enable
Clients to correlate the End-User's activities without permission.
When pairwise Subject Identifiers are used, the OpenID Provider MUST calculate a unique sub
(subject) value for each Sector Identifier. The Subject Identifier value
MUST NOT be reversible by any party other than the OpenID Provider.
If the client has not provided a value for sector_identifier_uri in
dynamic client Registration, the sector identifier used for
pairwise identifier calculation is the host component of the registered redirect_uri.
If there are multiple host names in the registered redirect_uris,
the Client MUST register a sector_identifier_uri.
When a sector_identifier_uri is provided, the host component of that URL is used as the sector
identifier for the pairwise identifier calculation. The value of the sector_identifier_uri MUST
be a URL using the https scheme that points to a JSON file containing an array of redirect_uri values.
The values of the registered redirect_uris MUST be included in the elements of the array.