On my university we have eduroam network. We use personal certificates to enable connection. TLS WPA2 Enterprise it is. I simply cant use my private key(p12) it shows error decrypting certificate. Certificate is vaild. It works when I use openssl command line. It works on windows, ubuntu/mint. Basically nothing's wrong with it. On the same computer I have xfce4 on which it works. Only on kde it has problem. I used old and new network manager applet(new is buggy) I guess it has something to do with kleopatra. Importing normal CA certificate works though. Only private key has problems. Reproducible: Always Steps to Reproduce: 1. Connect to network using pksc12(p12) certificate/ Try to import pksc12 certificate 2. 3. Actual Results: Error decrypting certificate. Expected Results: Just import/connect to network I don't know if its important but its manjaro distribiution of arch linux. It has the same packages though.
I can't reproduce this problem. I often test with p12 files and certificates in them. One cause for this could have been gnome-keyring hjacking the gpg-agent which generally broke down S/MIME support in Kleopatra because all operations that worked with secret keys were broken for S/MIME You might want to check out: https://wiki.gnupg.org/GnomeKeyring If you run: echo $GPG_AGENT_INFO and see the word keyring in the output you can be sure that this is the cause.
Resolving this as worksforme, I've tested it with multiple certificates and it worksforme. At least with a recent version 16.04 or 16.08.