Which of the following encryption methods uses a matching pair of key-codes, securely distributed,
which are used once-and-only-once to encode and decode a single message?

A.
Blowfish

B.
Tripwire

C.
certificate

D.
DES

E.
one-time pad

F.
None of the choices.

Explanation:
It’s possible to protect messages in transit by means of cryptography. One method of encryption –
-the one-time pad –has been proven to be unbreakable when correctly used. This method uses a
matching pair of key- codes, securely distributed, which are used once-and-only-once to encode
and decode a single message. Note that this method is difficult to use securely, and is highly
inconvenient as well.