How to see if a message is digitally signed using CDO

[Jesper J.]

am programming against the Outlook API and CDO in C++. We already have code that is invoked by a button (added to the Outlook button bar by our integration-code) in Outlook which will extract the selected message with its attachments and save them to a file for further processing. I now need to extend our solution to extract information on encryption and/or digital signatures for the selected message. All of this information is present somehow in Outlook, because it can be seen in the user interface. The problem is what is exposed in the APIs

So, given an Outlook mail item, I need to detect

Was the email digitally signed?
Was it encrypted?
For a digital signature: could its validity be confirmed? (including time-validity, check against Certificate Revocation List, check of the complete certificate chain up to and including a trusted root). If possible, we would also like to be able to extract the certificate itself.
For an encrypted email: was decryption successful?
If validity could not be confirmed (or decryption not be done) some indication of the cause, if possible
After having looked closer at the Outlook Object Model, we have only partly found an answer to (1) and (2). We found no answers for the remaining questions

Re. (1) and (2): From an Outlook Mail item ID, we can create a CDO Message object and from that extract the two properties Signed and Encrypted. Initially, we assumed these to make up for answering (1) og (2), but experiments with the Outlook versions 2000, 2002 and 2003 show that these attributes are always False. We have read the knowledge base article 194623 entitled "HOWTO: Use CDO (1.x) to See if a Message Is Signed and/or Encrypted", which indicates that these flags are not set reliably by Outlook 98, but apparently this goes for the newer versions of Outlook as well. The article then suggests reading the message class. For all 3 Outlook versions, I then find these values

unsigned, unencrypted: IPM.Note
signed, unencrypted: IPM.Note.SMIME.MultipartSigned
unsigned, encrypted: IPM.Note.SMIME
signed, encrypted: IPM.Note.SMIM

The problem here is that the latter two are not distinguished. We have failed to find some other way of distinguishing. Another problem is that I have failed to find any properties telling me whether the signature/encryption certificate was found valid

 

[Ken Slovak - [MVP - Outlook]]

See http://support.microsoft.com/?kbid=194623

am programming against the Outlook API and CDO in C++. We already

have code that is invoked by a button (added to the Outlook button bar
by our integration-code) in Outlook which will extract the selected
message with its attachments and save them to a file for further
processing. I now need to extend our solution to extract information
on encryption and/or digital signatures for the selected message. All
of this information is present somehow in Outlook, because it can be
seen in the user interface. The problem is what is exposed in the
APIs.

So, given an Outlook mail item, I need to detect:

Was the email digitally signed?
Was it encrypted?
For a digital signature: could its validity be confirmed? (including

time-validity, check against Certificate Revocation List, check of the
complete certificate chain up to and including a trusted root). If
possible, we would also like to be able to extract the certificate
itself.

For an encrypted email: was decryption successful?
If validity could not be confirmed (or decryption not be done) some

indication of the cause, if possible.

After having looked closer at the Outlook Object Model, we have only

partly found an answer to (1) and (2). We found no answers for the
remaining questions.

Re. (1) and (2): From an Outlook Mail item ID, we can create a CDO

Message object and from that extract the two properties Signed and
Encrypted. Initially, we assumed these to make up for answering (1) og
(2), but experiments with the Outlook versions 2000, 2002 and 2003
show that these attributes are always False. We have read the
knowledge base article 194623 entitled "HOWTO: Use CDO (1.x) to See if
a Message Is Signed and/or Encrypted", which indicates that these
flags are not set reliably by Outlook 98, but apparently this goes for
the newer versions of Outlook as well. The article then suggests
reading the message class. For all 3 Outlook versions, I then find
these values:

unsigned, unencrypted: IPM.Note
signed, unencrypted: IPM.Note.SMIME.MultipartSigned
unsigned, encrypted: IPM.Note.SMIME
signed, encrypted: IPM.Note.SMIME

The problem here is that the latter two are not distinguished. We

have failed to find some other way of distinguishing. Another problem
is that I have failed to find any properties telling me whether the
signature/encryption certificate was found valid.