Secure PDF Document Transmission for US State Government Official
I have been requested to send a copy of a past year tax return to a US state office. I have been in contact with a tax official by email to send this copy through various means. This state is a few thousand miles away from my current residence.
What would be the most- to least- information-safe approaches to transmitting this tax document out of the following options this official currently has: email, fax, paper mail?
What I have done is the following:
I have asked the official about secure methods to send an electronic copy besides email, and the tax official responded that email is safe. I personally do not feel it is safe to send unencrypted messages of sensitive documents by email.
I have also looked into encrypting this document and sharing the decryption key over the phone with this tax official. But I got stuck currently on a good way to encrypt with my Debian Linux OS in a way that a tax official would be able to open.
I also have my own domain name that I could point the official to, and a cloud-provided server instance resolving requests to this domain as another option.
