Presently, I receive e-mail attachments from many different senders. Due to the contents of the file attachments, I want them to be protected (i.e. encrypted) while in transit to me.
How can the senders send these files to me securely? Is there a simple solution that would work for senders without much technical know-how? It's OK if they're sent via a method other than e-mail too.
Edit:
The files contain payroll data, so they should only be readable by the sender and myself while in transit. Once I receive the files, they'll be stored on my secured system and will no longer need protection.