Hello,
When saving a VCF contact, how to sign it? If not implemented, can you please register a feature request for that? My guess is that it’s pretty easy, inside the VCF, the whole thing goes below:
KEY;X509;ENCODING=BASE64:
encoded string which wraps at character # 74
And if you think not worth to add, can you please advise how to add it myself to the MemoryStream when saving:
MapiContact.Save(ms, vcfSaveOpt)
and
VCardContact.Save(ms, vcfSaveOpt)
Thanks 
Hello,
We’ll look into it and get back to you.
Hi @australian.dev.nerds
The KEY header according to the specification (RFC 6350 - vCard Format Specification) stores the public key or authentication certificate associated with the VCard object. To send a contact file via email, you can add it to MailMessge’s AlternateViewCollection as an AlternateView with content type “text/vcard” and sign the message.
In our opinion, file signing is not the responsibility of the Aspose.Email API, instead you can use any other common methods for this. For example cryptography - Digital signature for a file using openssl - Stack Overflow