https://learn.microsoft.com/en-us/dotnet/api/system.web.security.membershipprovider.passwordformat?view=netframework-4.8.1&redirectedfrom=MSDN
MembershipProvider.PasswordFormat Property (System.Web.Security) | Microsoft Learn
Gets a value indicating the format for storing passwords in the membership data store.
property systemweb securitymicrosoftlearn