9.5 Symmetric Encryption
Blowfish
A keyed symmetric block cipher that was intended to be free of the problems associated with other algorithms and replace DES.
What type of key or keys are used in symmetric cryptography?
A shared private key
You want to encrypt data on a removable storage device. Which encryption method would you choose to use the strongest method possible?
AES
Triple DES (3DES)
An enhanced version of DES.
Advanced encryption standard (AES)
An iterative symmetric-key block cipher that was developed as a replacement for DES in 2001.
Which of the following is considered an out-of-band distribution method for private key encryption?
Copying the key to a USB drive
Which of the following is the weakest symmetric encryption method?
DES
Which of the following symmetric cryptography systems does not support a variable block size?
IDEA
Which of the following symmetric block ciphers does NOT use a variable block length?
International Data Encryption Algorithm (IDEA)
How many keys are used with symmetric key cryptography?
One
Which of the following can be classified as a stream cipher?
RC4
Which of the following is the most frequently used symmetric key stream cipher?
Ron's Cipher v4 (RC4)
What form of cryptography is best suited for bulk encryption because it is so fast?
Symmetric key cryptography
Which of the following forms of cryptography is best implemented in hardware?
Symmetric stream
Stream cipher
A symmetric encryption that is performed on each bit within a stream of data in real time.
Block cipher
A symmetric encryption that transposes plaintext to ciphertext in chunks (block by block).
Data encryption standard (DES)
A very popular symmetric cryptography method created by the National Security Agency (NSA) that was one of the first symmetric encryption methods and is now obsolete due to known weaknesses.
Which of the following encryption mechanisms offers the least security because of weak keys?
DES
The sender's key is sent to a recipient using a Diffie-Hellman key exchange.
In-band distribution
The sender's key is sent to the recipient using public key cryptography.
In-band distribution
The sender's key is burned to a CD and handed to the recipient.
Out-of-band distribution
The sender's key is copied to a USB drive and handed to the recipient
Out-of-band distribution
Which version of the Rivest Cipher is a block cipher that supports variable bit length keys and variable bit block sizes?
RC5
Twofish
A symmetric block cipher that permits a wide variety of tradeoffs between speed, software size, key setup time, and memory.
Skipjack
A symmetric cryptography method created by the NSA that uses the Clipper chip (Very Large Scale Integration) device with an Advanced RISC Machine (ARM).
Ron's cipher v5 or Ron's code v5 (RC5)
A symmetric cryptography method that implements a symmetric-key block cipher cryptographic algorithm produced by RSA Security, Inc.
Ron's cipher v2 or Ron's code v2 (RC2)
A symmetric cryptography method that implements a variable-key-sized block cipher and was designed to replace DES.
International Data Encryption Algorithm (IDEA)
A symmetric cryptography method that is a minor revision of an earlier PES (Proposed Encryption Standard) that uses 64-bit blocks with 128-bit keys and is employed by Pretty Good Privacy (PGP) email encryption.
Which of the following are true of Triple DES (3DES)? (select two)
Uses a 168-bit key Is used in IPsec
