I look for a 100% Linux solution to use Sweden's BankId.
There is information online:
- https://github.com/virtualforce/bankid-authentication/
- http://www.herlitz.nu/2017/09/13/integrating-with-swedish-bankid-and-.net/
Now I need to download my client certificate from the bank seb.se
How to download one's client certificate at SEB?
It's not really clear what you want.
Do you want a Linux BankID client? That's not supported by BankID. You can find out their client requirements here: https://support.bankid.com/sv/felavhjalpning/systemkrav
Do you want a server solution for using BankID RP interface? Go ahead, the SOAP interface is well documented here: https://www.bankid.com/rp/info
As for downloading the certificate from SEB, you need to be a bank customer with a Swedish personal number. I'm not a customer, but judging from their website, it seems they only issue BankID on card and Mobile BankID. Once you're logged into the Internet bank with your Digipass you should have no problem to find out how to issue a mobile BankID.
BankID on card might take some more effort though.
BankID does have a demo system for development purposes. There you can issue a fake BankID to use in the development mode, "test".