I have just been issued a Digital Certificate from Exostar FIS, for Digital Signature (as detailed in the KU extension). In the Digital ID and Trusted Certificate Settings menu I can see it, I can view it, but I can't select "Use for Signing". Why not?
Signature algorithm: SHA256 RSA
Validity ends: 2018/03/07
Key usage: Digital Signature
EKU: Client Authentication; 22.214.171.124.126.96.36.199
Public Key: RSA (2048 bits)
Location: Windows Cert Store
You may have to check with certificate issuer.
There have been some changes in this area.If the certificate has not a particular value the certificate won't be used for signature purposes. You may visit this page A: Changes Across Releases — Digital Signatures Guide for IT
From the link in your response I see no reason the Exostar Certificate would not be allowed for signing. What are the criteria Reader DC uses to determine if a certificate can be used for signing? I can then confirm with the issuer if their certificate meets these requirements.
Let us know how the certificate issuer respond to your query about the requirements of the certificate with Reader?