Symmetric Cryptography - Confusion / Diffusion etc ...

Question 1

attempt to remove letter frequency characteristics in plain text from appearing in ciphertext, done by substitution.

Answer 1

Confusion

Question 2

change to one character in plaintext affects multiple characters in ciphertext, done by transposition.

When done confusion/diffusion creates Avalance which means small changes in input results in large effects in output.

Answer 2

Diffusion

Question 3

(1) synchronous is what type of cipher ?

(2) asynchronous is what type of cipher ?

Answer 3

(1) Stream Cipher / (2) Block Cipher

Question 4

??? science of transforming info into unitelligible form.

??? study of both cryptography and cryptanalysis.

??? all parts that make up system to carry out encrypt/decypt process. PGP, PKI

Answer 4

Cryptography / Cryptology / Cryptosystem

Question 5

study of finding weaknesses in ciphers.

Answer 5

Cryptanalysis

Question 6

??? method used to encode characters to hide their value.

??? process of decrypting encrypted text.

Answer 6

Cipher / Decipher

Question 7

instance when 2 different keys generate same cipher text.

Answer 7

key clustering

Question 8

can also be called -> secret key, private key, shared key, same key, single key, session key; best for bulk encryption, both parties share the same key.

Answer 8

Symmetric Cryptography

Question 9

Disadvantages : exchanging of shared secret key, trust between parties sharing the key, management of keys -> n(n-1)/2, no authentication or non-repudiation.

Advantages : less computationally intensive, produces smaller file size, allows for faster transmissions.

Answer 9

ADV / DISADV of Symmetric Cryptography

Question 10

entire key space should be used, random key generation should be used (IV), strong keys should be used, keys should be longer than the message, key management and security should be in place.

Answer 10

Symmetric Cryptography