Key Use
The major issue is length of key use, and therefore frequency of replacement. Because it increases any attackers required effort, keys should be frequently changed. This also limits loss of information, as the number of stored encrypted messages which will become readable when a key is found will decrease as the frequency of key change increases. Historically, symmetric keys have been used for long periods in situations in which key exchange was very difficult or only possible intermittently. Ideally, the symmetric key should change with each message or interaction, so that only that message will become readable if the key is learned (e.g., stolen, cryptanalyzed, or social engineered).
Read more about this topic: Key Management
Famous quotes containing the word key:
“Now narrow minds can develop as well through persecution as through benevolence; they can assure themselves of their power by tyrannizing cruelly or beneficently over others; they go the way their nature guides them. Add to this the guidance of interest, and you will have the key to most social riddles.”
—Honoré De Balzac (1799–1850)
“The word “forbearance” is the key to a happy home.”
—Chinese proverb.