> Microsoft has addressed your issues 1-a, 1-b and 1-c by adding a > property "ViewStateUserKey" to the System.Web.UI.Page class in > .NET Framework 1.1. The documentation for this property is here: No, I think this statement is simply not true. The key is intended to solve a wholly different class of problems, and has nothing to do with replay attacks I reported. Reported issue 1-a: same user moves __VIEWSTATE from one page to another. Adding unique user identifier to __VIEWSTATE does not help, because in both cases, it's precisely the same user within the same system. Reported issue 1-b: same user retains __VIEWSTATE and reuses it at a later date. Again, it's precisely the same person and the same unique ID. Reported issue 1-c: this is the least relevant of all reported problems, and indeed can be in some situations mitigated by binding __VIEWSTATE data to a specific user. /mz
