Cryptography

Question 1

Plaintext or Cleartext

Answer 1

Original message, readable by attacker

Question 2

Ciphertext or Cryptogram

Answer 2

Altered message that is unreadable to anyone except the intended recipients, unreadable by attacker

Question 3

Encryption

Answer 3

Process of converting plaintext to ciphertext

Question 4

Decryption

Answer 4

Going from ciphertext to plaintext using the cryptographic algorithm and the key

Question 5

Algorithm

Answer 5

Mathematical function used in the encryption and decryption process

Question 6

Key or Cryptovariable

Answer 6

Sequence that controls the operation of the cryptographic algorithm, determines behavior of algorithm and permits reliable encryption and decryption of message

Question 7

Nonrepudiation

Answer 7

Security service by which evidence is maintained so that the sender and the receiver of data cannot deny having participated in the communication

Question 8

Cryptosystem

Answer 8

Entire cryptographic operation (including algorithm, key, and key management functions)

Question 9

Cryptanalysis

Answer 9

Study of techniques for defeating cryptographic techniques and by extension security services

Question 10

Cryptology

Answer 10

Science that deals with hidden, disguised or encrypted communications
Includes communications security and communications intelligence

Question 11

Collision

Answer 11

Occurs when a hash function generates the same output for different inputs

Question 12

Key Space

Answer 12

Total number of possible values of keys in a cryptographic algorithm or other security mechanism
2^n (n=length of key in bits)

Question 13

Work Factor

Answer 13

Time and effort required to break a protective measure

Question 14

Initialization Vector (IV)

Answer 14

Non-secret binary vector (block of bits) used as the initializing input for the encryption of a plaintext sequence
Increases security by introducing additional cryptographic variance to create unique ciphertext using the same key
Must be known to the recipient to decrypt message

Question 15

Encoding and Decoding

Answer 15

Encoding: action of changing a message to another format through the use of a code (i.e. message to Morse)
Decoding: converting encoded message into plaintext
*Has nothing to do with encryption

Question 16

Transposition or Permutation

Answer 16

Reordering plaintext to hide the message

Question 17

Substitution

Answer 17

Process of exchanging one letter (or byte) for another

Question 18

SP-Network

Answer 18

Substitution and Permutation

Adds confusion and diffusion to the process

Question 19

Confusion

Answer 19

Provided by mixing/changing key values used during the repeated rounds of encryption

Question 20

Diffusion

Answer 20

Mixing up the location of the plaintext throughout the ciphertext
Location of first character of plaintext may change several times during the encryption process due to transposition

Question 21

Avalanche Effect

Answer 21

Designing algorithms where a minor change in either the key or the plaintext will have a significant change in the resulting ciphertext
Confusion and diffusion
Strong hashing algorithm

Question 22

Link Encryption

Answer 22

Encrypts all data along communications path (including router information which provides traffic confidentiality)

Question 23

End-to-End Encryption

Answer 23

Data is encrypted in the beginning and is not decrypted until it reaches the end
Usually performed by end-user
Routing information remains visible