Give brief definitions of each of the following terms.

a. cryptography
b. Data Encryption Standard (DES)
c. privacy problem
d. integrity problem
e. problem of nonrepudiation
f. plaintext
g. ciphertext.
h. unsecure channel
i. eavesdropper
j. cryptanalysis

a. Cryptography is the use of data transformations to make the data incomprehensible
to all except its intended users.
b. The Data Encryption Standard is a symmetric encryption scheme; the same key
is used for both encryption and decryption.
c. The privacy problem is concerned with preventing the unauthorized extraction
of information from a communication channel.
d. The authentication problem is concerned with preventing one’s opponents from
modifying a transmission or inserting false data into a transmission.
e. This problem is concerned with legally proving that a message was either sent or
received
f The unencrypted message.
g. The encrypted text.
h. A channel that may be monitored or tapped by an eavesdropper.
i. Aperson or system that taps into an insecure channel to listen to messages sent
between two other parties.
j. Cryptanalysis is the practice of trying to decipher ciphertext without knowledge
of the decryption key.