CIS 460 MIDTERM REVIEW Part 3: Basic Encryption and Cryptography

True or false: Rivest-Shamir-Adleman, or RSA, is an algorithm used for symmetric key cryptography.

False

True of False: Private key encryption is the most secure transmission

False Private key encryption is the least secure transmission

True or False: Secure Hash Algorithm is less secure than MD5

False Secure Hash Algorithm is more secure than MD5

True or False: The five basic informations protections cryptography provides are Confidentiality, Privacy, Accountability, Integrity and Reliability.

False The five basic informations protections cryptography provides are Confidentiality, Integrity, Availability, Authenticity, and Non-repudiation

Name the only advantage of a stream cipher

Fast if it is short

List the four types of Stream Ciphers

1. Substitution cipher 2. Homo-alpha substitution cipher 3. Transposition cipher 4. RC4

What are the two most strategic uses for encryption?

1. To secure info during transmission 2. To secure stored information /data​

List the three types of block ciphers

1. Data Encryption Standard (DES) 2. Triple Data Encryption Standard (3DES) 3. Advanced Encryption Standard (AES)​

Name the five types of software encryption techniques.

1. File and File System Cryptography 2. Protects Groups of Files 3. Pretty Good Privacy (PGP) 4. GNU Privacy Guard (GPG) 5. Whole Disk Encryption

What are the four secure hashing algorithm characteristics?

1. Fixed Length / Size Hash Code​ 2. Is Unique 3. Proves Original Hash Value 4. Secure

List the three ways hashing can be used for integrity checks.

1. Hashing used to establish message / data 2. Hashed Message Authentication Code 3. Verify file integrity after download​

What are the four reasons why we need cryptography?

1. Increased use of Internet, e-commerce, electronic communications ​ 2. Increasing miniaturization of hardware-based ​ encryption products​ 3. Increasing use of private & public key cryptography 4. Continued cracking/ breaching of increasingly secure Crypto algorithms​

List the five common hashing algorithms

1. Message Digest (MD) ​2. Secure Hash Algorithm (SHA) ​3. Whirlpool Hash​ 4. RIPE-MD Hash​ 5. Password Hashes​

List the four parts of Cryptography

1. Plaintext/Data 2. Encryption 3. Ciphertext 4. Decryption

Name the five encryption techniques.

1. Private Key 2. Public Key 3. Digital Envelope 4. Digital Signatures 5. Hashing Techniques

What are the four asymmetric algorithm types?

1. RSA​ 2. Elliptic curve cryptography (ECC) ​3. Quantum cryptography​ 4. N-TRUEncypt​​

Name one reason why block ciphers are more secure.

- (block) output is more random​ - Cipher set to original state after each block used​ - "Padding" cipher adds more complexity​

Name one disadvantage of a stream cipher?

- Consumes more processing power if plaintext is long​ - More prone to attack because (engine generating) stream cipher does not vary (only the plain text changes)​ - Attacker can identify stream + ID the Key to crack ​

What are the five types of hardware encryption techniques?

1.Cryptography can be embedded in hardware​ 2. USB device encryption, Encrypted flash drives​ 3. Hard disk drive encryption, ​ 4. Trusted Platform Module (TPM)​ 5. Hardware Security Module (HSM)​

What is RIPEMD?

2 different and independent parallel chains of computation​ that are combined at end of process​ ​

What is a whirlpool hash?

A 512-bit hash

What is the key difference between a cipher and a code?

A cipher is an algorithm where as a code is a specific type of cipher

What is encryption?

A specific process / algorithm used to​ create a "coded" message

What is a one-time pad?

A type of substitution cipher that is absolutely unbreakable. Uses a block of shift keys of size n, each chosen at random

If Bob wants to send a secure message to Alice using an asymmetric cryptographic algorithm, which key does he use to encrypt the message?

Alice's public key

Which One Of The Following Statements About Block And Stream Ciphers Is Correct? A. Stream ciphers commonly use Feistel networks. B. Block ciphers are faster than equivalent stream ciphers. C. Most modern ciphers are block ciphers. D. Block ciphers encrypt one byte at a time.

C. Most modern ciphers are block ciphers.

What is the key difference between cryptography and encryption?

Cryptography is a study whereas encryption is an algorithm/process.

What is cryptography?

Cryptography is the practice and study of techniques for securing information and communication mainly to protect the data from third parties that the data is not intended for.

What are hash tables?

Data structure ("array") use for rapid "hash value" lookup ​

List the two key differences between hash and encryption

Hashing: One-way function, and any size input to be hashed that yields the same fixed-length output Encryption: Reversible and different input yields approximately same size crypto

What are the weaknesses of One time pad?

Key needs to be same length as plaintext, and Key can never be reused else the xor of the plaintexts will be leaked

Salting defends against what kind of attacks?

Password attacks

What is the key difference between private and public keys?

Public Key is encryption, and has two keys Private keys is decryption and the right side of the crypto key is always the private key

Alexei was given a key to a substitution cipher. The key showed that the entire alphabet was rotated 13 steps. What type of cipher is this?

ROT13

An algorithm for digitally signing data with a private key such that anyone with possession of the corresponding public key can verify the signature.

RSA

A widely used, standardized cryptographic hash function.

SHA256

What is the difference between Steganography and Cryptography?

Steganography means covered writing. Cryptography means secret writing.

Draw a substitution cipher and draw a transposition

Substitution Cipher file:///Users/admin/Desktop/Screen%20Shot%202021-10-03%20at%201.14.31%20PM.png Transposition Cipher file:///Users/admin/Desktop/Screen%20Shot%202021-10-03%20at%201.14.45%20PM.png file:///Users/admin/Desktop/Screen%20Shot%202021-10-03%20at%201.16.43%20PM.png

What is the difference between substitution cipher and transposition cipher?

Substitution cipher is 1 input = 1 cipher Transposition cipher = rearranges characters but does not change them

What is padding?​

Taking original text /data that may not be the same assigned size of its original Block Cipher (e.g. 32,64,512 bit cipher block) and adding random bits ​to extend cipher (code) to fit larger Block size​.​

What is the main disadvantage of private key encryption?

The same key is used for encryption and decryption

TRUE or FALSE: If Alice has a message to send to Bob and she wants to encrypt the message using asymmetric cryptography so that no one other than Bob can read it, she does so by using Bob's public key.

True

True or False: Blowfish is a type of block cipher

True

True or False: One-time pad is considered the MOST secure cipher of all time.

True

What is a digital envelope?

Use private key to encode a msg, then use public key to carry the private key (more efficient than using public key for everything) combo of private key + public keys​ + "secret session key" (for digital envelope)​

In the DES algorithm the round key is __________ bit and the Round Input is ____________ bits. a) 48, 32 b) 64,32 c) 56, 24 d) 32, 32

a) 48, 32

Which of the following key lengths is not supported by AES? a) 64 bits. b) 128 bits. c) 192 bits. d) 256 bits

a) 64 bits.

What is the difference between DES and AES? a) AES uses larger keys and is therefore more secure than DES. b) AES is a block cipher while DES is a stream cipher. c) AES is experimental and largely untested while DES is still used by the NSA for encryption. d) AES must be applied three times in order to be as secure as DES.

a) AES uses larger keys and is therefore more secure than DES.

There is an addition of round key before the start of the AES round algorithms. a) True b) False

a) True

Message Digest 2 (MD2) takes plaintext of _________________ ​and creates a ______ bit hash. a. any length and 512 b. any length and 256 c. any length and 64 d. any length and 128​

any length and 128

Which of the following properties must a cryptographic hash function provide? Select three. a) Key revocation. b) Collision resistance. c) A deterministic mapping from input to output. d) One-to-one mapping of input to output. e) Difficulty of finding an input that matches a given hash. f) None of the above.

b) Collision resistance. c) A deterministic mapping from input to output. e) Difficulty of finding an input that matches a given hash.

In the DES algorithm the 64 bit key input is shortened to 56 bits by ignoring every 4th bit. a) True b) False

b) False

In the DES algorithm, although the key size is 64 bits only 48bits are used for the encryption procedure, the rest are parity bits. a) True b) False

b) False

If any change is made to any of original info / data , the hash code will _______________. a. no change b. change dramatically c. change slightly ​

b. change dramatically

Salted PW hashes words​ are _________________ in "common word" lists​. a. easily found b. not found ​

b. not found

What is the name of the method in which letters are rearranged to create the ciphertext? a. enigma b. transposition c. substitution d. one-time pad

b. transposition

What is the difference between stream ciphers and block ciphers? a) Stream ciphers use the same key for both encryption and decryption. Block ciphers use different keys. b) Stream ciphers use different keys for encryption and decryption. Block ciphers use the same key for both. c) Stream ciphers encrypt one bit at a time. Block ciphers encrypt an entire block at a time. d) Stream ciphers encrypt an entire block at a time. Block ciphers encrypt a single bit at a time.

c) Stream ciphers encrypt one bit at a time. Block ciphers encrypt an entire block at a time.

How long would a 10-bit message be after being encrypted by a stream cipher? a. 2 bits b. 5 bits c. 10 bits d. 20 bits

c. 10 bits

The Advanced Data Encryption Standard (AES) in an encryption technique of __________________. a. Symmetric b. Modulation c. Asymmetric d. Algorithmic

c. Asymmetric

A hash is a _______ way code. a. three b. two c. one d. four

c. one

What type of cipher encrypts plaintext one byte or one bit at a time? a. block b. elliptical c. stream d. enigma e. hash

c. stream

AES uses a ____________ bit block size and a key size of __________ bits. a) 128; 128 or 256 b) 64; 128 or 192 c) 256; 128, 192, or 256 d) 128; 128, 192, or 256

d) 128; 128, 192, or 256

The DES Algorithm Cipher System consists of ____________ rounds, (iterations) each with a round key. a) 12 b) 18 c) 9 d) 16

d) 16

Why is a one-time pad impractical for everyday cryptography? a) True random number generators (TRNGs) are not a standard part of most computational devices. b) A key stream for a one-time pad must be securely delivered to all communicating parties without being compromised. c) A key stream for a one-time pad can only be used once. d) All of the above.

d) All of the above

What is a widely used privacy-ensuring program by individuals and corporations? a. Digital Signature Standard b. Online Certificate Status Protocol c. Secure HTTP d. Pretty Good Privacy

d. Pretty Good Privacy

Draw the Cryptography, Encryption and Cipher Diagram

file:///Users/admin/Desktop/Screen%20Shot%202021-10-03%20at%2011.40.00%20AM.pdf

Draw the basic encryption-decryption process

file:///Users/admin/Desktop/Screen%20Shot%202021-10-03%20at%2011.51.53%20AM.png

Draw the symmetric encryption process

file:///Users/admin/Desktop/Screen%20Shot%202021-10-03%20at%2011.52.39%20AM.png

Draw the asymmetric process

file:///Users/admin/Desktop/Screen%20Shot%202021-10-03%20at%2011.56.02%20AM.png

Draw the process of digital envelope encryption

file:///Users/admin/Desktop/Screen%20Shot%202021-10-03%20at%2011.58.21%20AM.png

Draw the digital signature process in a diagram.

file:///Users/admin/Desktop/Screen%20Shot%202021-10-03%20at%2011.59.51%20AM.png

Draw the password to password hash process

file:///Users/admin/Desktop/Screen%20Shot%202021-10-03%20at%2012.37.35%20PM.png