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Trying to open an smime.p7s email attachment that looks like this?
Email and Document Signing Certificates are a fantastic product that haven’t managed to become ubiquitous yet owing to the fact that they are still unsupported by many mail clients. That lack of universal support has led to one of the most common questions people have about their email: what is an smime.p7s file? And how do I open it?
S/MIME stands for Secure/Multipurpose Internet Mail Extensions, the SMIME.p7s file format is the digital signature that is sent alongside a digitally signed email. If you’re receiving emails with an SMIME.ps7 attachment in the email, it means that the sender has an Email Signing certificate installed on their computer. If your email client supports Email Signing you will see the verified name of the sender. Microsoft Outlook represents this with a little ribbon, for example, like this:
When you click on the ribbon or whatever Icon accompanies the verified sender field, you will be greeted with validated information on the sender, including who issued the Email signing certificate in the first place:
With a digital signature, you can sign and/or encrypt the emails you send to others. You can easily purchase and install your own digital certificate in Microsoft Outlook or other email program to sign and encrypt messages.
Technically you can open a p7s file in Microsoft Outlook, but it’s not really a file that’s necessarily meant for a user to open, it’s their for the email client to authenticate the sender of the secure email message. There’s not really much you get out of opening it.
Email & Document Signing Certificates are called CPACs (Comodo Personal Authentication Certificates) and can be used to sign both emails and certain kinds of documents. Signing accomplishes several things:
These are all great things, especially for larger companies and organizations.