The ABCS of cryptography

A primary requirement for a good cryptographic hash function is that the function should not produce too many collisions. A collision in a hash function is when:

2 inputs map to the same output.

Compute the value of: 23 mod 4 = ?

3

Which of the following methods are effective in cracking the Caesar cipher?

Brute force and letter frequency analysis

Encrypted information is only viewable by authorized users who have the correct key to decrypt. This describes which aspect of the CIA triad?

Confidentiality

Encryption plays a crucial role in maintaining which part(s) of the CIA triad?

Confidentiality and Integrity

Which of the following shows the word "CAT" encrypted with the Caesar cipher with a key of 1?

DBU

True or False: A message in unencrypted form is called ciphertext.

False

True or False: Cracking a Vigenère cipher with brute force takes longer than a Caesar cipher, but it is still a reliable method for cracking the encryption.

False

Public-key cryptography (a form of asymmetric cryptography) is an encryption method that's widely used because: I. It is computationally infeasible to compute the private key based on the public key. II. It's easier to share one public key than billions of private keys. III. It's much tougher to crack an asymmetric encryption than a symmetric one. IV. It's more secure because the private keys do not ever need to be transmitted or revealed to anyone.

I - IV all

Most attacks on hash functions involve: I. Finding collisions. II. Injecting a new hash function into the code. III. Pre-generating millions of hashes and comparing them to the plain text that generated it. IV. Really good random guessing.

I, II and III

Which of the following shows the word "DOG" encrypted with the Caesar cipher with a key of 5?

ITL

Cryptography is defined as:

The practice of encoding information so only authorized people can read it

Why do we use cryptography?

To secure digital and non-digital data To allow important messages to be sent with lower chances of being interpreted To add security to the use of specific machinery

Hash functions got the name "hash" because it's easy to compute the function with a given input, but nearly impossible to reverse engineer the hash function to get the original input.

True

True or False: Computers have made it easier and faster to crack the Caesar cipher.

True

What is the primary flaw with the Caesar Cipher and other substitution ciphers?

With enough frequency, a message could be decrypted

To decrypt an encrypted message, pass the encrypted message and the _____ to the decrypt function.

key

An encryption method that uses a series of interwoven Caesar ciphers based on the letters of a keyword is called

the Vigenère Cipher

Asymmetric encryption:

uses one key for encryption and a different key for decryption

Symmetric encryption:

uses the same key for encryption and decryption