[mfzxmirx] Signed bills and statements

Bank and credit card statements, and other bills delivered by email, encrypted and signed with public key encryption would be ideal, but stymied by usability issues of public key decryption.

Next best is for the statements to be stored online, protected by authentication mechanisms, and a signed hash of the statement to be delivered by email.  There should be an initialization vector.  This way, the sender cannot alter the stored statement without the user's knowledge.