I received a signed message that has the “red medal” icon – “The digital signature on this message is Valid and Trusted”.
Now I’d like to programatically decide whether it was tampered or it is valid and trusted. I see the message has some property –
http://schemas.microsoft.com/mapi/string/{41F28F13-83F4-4114-A584-EEDB5A6B0BFF}/IsSigned
But that’s not good enough since it’s internal Outlook property (doesn’t exist in Hotmail Connector for an example). How can I tell whether it was tampered or not?
Thanks a lot! 🙂
Nili
Unfortunately, Outlook Object Model or Extended MAPI expose no such information. You would need to programmatically process the p7m (or the raw MIME in case of clear signed) attachment.
Read more at http://social.msdn.microsoft.com/Forums/en-US/outlookdev/thread/c8a9caf3-18b0-448e-9882-047d6afe5904