Symmetric Key Cryptography — Test 1

Correct Answer: B. B. Public key cryptography
Explanation: Cryptography is mainly categorized into two types; symmetric key cryptography and asymmetric key cryptography(public key cryptography). Symmetric key cryptography uses only one key for both encryption and decryption.

Correct Answer: D. D. Juhhw khu
Explanation: Caesar cipher is the substitution cipher, which belongs to classical cryptography. Cipher text will be obtained by replacing the plain text letters with letters three places further from them. If further letter is ‘z’, then process will circularly follows ‘a’.

Correct Answer: A. A. Tkmtteataeeohpry
Explanation: Rail fence is the transposition technique, that belongs to classical cryptography. First the plain text is written in a sequence of diagonals with defined number of rows, then the cipher text is read off as a sequence of all the rows from starting to end.

Correct Answer: B. B. Classical and modern
Explanation: Symmetric key cryptography has two types; classical and modern. Classical cryptography again divided into two types; transposition and substitution. Modern cryptography is of two types; stream cipher and block cipher.

Correct Answer: D. D. Diffie-hellman
Explanation: Diffie-Hellman is the first asymmetric cipher and well known for its logarithm computations. It is used at its best to transmit the secret key between users for further symmetric encryption of messages.

Correct Answer: D. D. Quick encryption and decryption
Explanation: Quick encryption and decryption is done in symmetric key cryptography. Because, it uses less resources and cipher text length will be small or same as plain text. It encrypts huge amount of data quickly and provides confidentiality.

Correct Answer: C. C. It uses single fixed length key for each algorithm
Explanation: An algorithm can make use of number of random keys and the keys can be any size. If the key length is increased, then it will become difficult to crack the key.

Correct Answer: D. D. Transmission of secret key
Explanation: Symmetric key cryptography uses single key to encrypt and decrypt messages. If the secret key is shared through an unsecured channel, then there will be a chance for attacking the key.

Correct Answer: D. D. Bitcoin’s block chain
Explanation: Unlike data security, cloud storage and user privacy, bitcoin uses elliptic-curve cryptography over symmetric key cryptography. Elliptic curve cryptography not only used for encryption, but also for digital signatures and random generators.

Correct Answer: A. A. True
Explanation: Asymmetric ciphers are much complex and slower than symmetric ciphers. Asymmetric ciphers have longer keys, which are more related to mathematics. As two keys are employed in asymmetric cipher, it is complex than symmetric ciphers.