Cryptography

Question 1

Algorithm

Answer 1

A computing procedure designed to perform a task such as encryption, decryption, compression, or hashing.

Question 2

Certificate

Answer 2

A digitally signed, special block of data that contains a public key and the identifying information for the entity, or principal, that owns the associated private key.

Question 3

Certificate Authority (CA)

Answer 3

A trusted entity or third party that issues and signs public key certificates, thereby attesting to the validity of the public keys.

Question 4

Ciphertext/ Cryptogram

Answer 4

This is the enciphered, encrypted, or scrambled form of a message.

Question 5

Collisions

Answer 5

Where two different messages would provide the same hash or digest value.

Question 6

Cryptanalysis

Answer 6

The practice of defeating the protective properties of cryptography. Reading protected information, altering messages or integrity values, and violating authentication schemes are all forms of cryptanalysis. The practice of testing cryptographic algorithms to determine their strength or resistance to compromise is also a form of cryptanalysis.

Question 7

Cryptography

Answer 7

The word cryptography is based on the Greek words “kryptos” (hidden) and “grafi” (writing). It is a mathematical manipulation of information that prevents the information from being disclosed or altered.

Question 8

Cryptology

Answer 8

The study of cryptography and cryptanalysis,

Question 9

Cryptanalysis

Answer 9

The practice of defeating the protective properties of cryptography.

Question 10

Cryptovariable (key)

Answer 10

The (often-secret) value used in the transformation of the message in a cryptographic operation that controls the operation of the algorithm in a unique, predictable manner.

Question 11

Decipher/ decrypt/ decode

Answer 11

Descrambling an encrypted message and converting it into plaintext.

Question 12

Digital Signature

Answer 12

Proves that the message has not been altered (Message Integrity), and it proves who sent the message (Proof of Origin and non-repudiation).

Question 13

Electronic Code Book (ECB)

Answer 13

Each block of plaintext is independently encrypted into a respective block of ciphertext. This can be down in parallel.

Question 14

Encrypt/ encipher

Answer 14

Scrambling a plaintext message by using an algorithm, usually in conjunction with a key.

Question 15

Exclusive-OR (XOR)

Answer 15

A basic transformation technique and another name for binary addition.

Question 16

Hash Functions

Answer 16

Used to ensure message integrity. For example, when a message is sent over a communications channel, it may be altered either accidentally or intentionally while in transit.

Question 17

Initialization Vector (IV)

Answer 17

A random value that is XOR’d with the plaintext message before encryption.

Question 18

Kerckhoff’s Principle

Answer 18

States that the strength cryptosystem is based on the secrecy of the key and not on the secrecy of the algorithm.

Question 19

Key Clustering

Answer 19

A weakness that would exist in a cryptosystem if two different keys would generate the same ciphertext from the same plaintext.

Question 20

Key space

Answer 20

The total number of keys available to the user of a cryptosystem.

Question 21

Non-repudiation

Answer 21

A security service by which evidence is maintained so that the sender and recipient of data cannot deny having participated in the communication. Referred to individually as non-repudiation of origin and non-repudiation of receipt.

Question 22

Plaintext/ Cleartext

Answer 22

This is the natural or human-readable form of a message.

Question 23

Registration Authority (RA)

Answer 23

The primary organization that verifies a certificate Applicant’s information and identity.

Question 24

Scytale Rod

Answer 24

A simple transposition cipher system that employs a rod of a certain thickness around which was wrapped a long, thin strip of parchment.

Question 25

Secure HTTP (S-HTTP)

Answer 25

A protocol for transmitting data securely over the World Wide Web designed to transmit individual messages securely.

Question 26

Secure Sockets Layer (SSL/TLS)

Answer 26

Uses two keys to encrypt data: a public key known to everyone and a private or secret key known only to the recipient of the message.

Question 27

Synchronous and Self-synchronous

Answer 27

An algorithm in which the keystream is generated based on the original key, bit-by-bit, in sync with the arrival of the plaintext.

Question 28

Transport Layer Security (TLS)

Answer 28

A protocol that guarantees privacy and data integrity between client/ server applications communicating over the Internet.

Question 29

Work Factor

Answer 29

An estimate of the effort/ time needed to overcome a protective measure by an attacker with specified expertise and resources.