How do I store user certificate and use private key to sign data?

I've been searching documentation, tutorials and forum but still can't find how to do this. If anyone has any idea, please shine some light my way :)

I need to store a CA issued certificate for each app user. If possible it would store to local storage and an SQL DB for a backup. This would be a one time event for each user.

Then I need the private key of that cert to sign user created data. This would be done whenever new data is created.

I haven't the foggiest how to do this with C3.

The certificate is probably in a form of text string, so you can simply store it in Local Storage. There are plenty of examples and tutorials.

But to sign any data you will need a script or addon. As far as I know, the official plugin doesn't support PKI cryptography, so you will need some third party solution.

The certificate is probably in a form of text string, so you can simply store it in Local Storage. There are plenty of examples and tutorials.

The certificate is a .p12 file. I went through many tutorial about Local Storage but I still don't see how to turn the certificate in something that I would be able to store. I'm missing something but I don't understand what it is.

But to sign any data you will need a script or addon. As far as I know, the official plugin doesn't support PKI cryptography, so you will need some third party solution.

Can anyone recommend a good solution?

It's possible to store binary files in Local Storage too.

I don't have a solution, you need to do some research, maybe hire an experienced programmer.

Here is a link I found which may be useful:

stackoverflow.com/questions/36018233/how-to-load-a-pkcs12-digital-certificate-with-javascript-webcrypto-api