Most software for sending e-mail carries pictures of envelopes, not postcards. Furthermore, most people use whatever software ships with their computer. And even if Internet users suspect they should do more to protect their e-mail, they figure there are bigger targets. That may be true about e-mailing photos or commenting about the weather. He would not name the company.
Many doctors refuse to respond to unencrypted e-mail.
Under that scheme, one key locks a message, and a different key unlocks it. People who want to receive encrypted mail distribute a public key that locks messages. A sender uses that person's public key to encrypt the message, which can be unlocked using only the recipient's private key. The first version of PGP appeared in June 1991. Zimmermann and the PGP team initially had trouble with the U.S. government, which considers encryption a form of munition.