IT 223 Lecture 8

brute force attack

A cryptography attack that tries every possible key value.

Algorithms

A defined sequence of operations.

Ciphers

A process for concealing the meaning of a message or a message concealed by such a process.

In cryptography, what is a cipher most often referring to?

Algorithm for performing encryption and decryption.

Public-key Cryptography (PKC)

Another name for Asymmetric Cryptography

Statistical Analysis

Attempting to find non-random patterns in intercepted cipher text that might reveal the plaintext, or even the key.

Exploiting public data

Attempting to learn private data by analyzing public data related to it.

Social engineering

Attempting to trick a user into revealing a key.

Which of the following Boolean operations is typically used in encryption algorithms?

Bitwise XOR

Symmetric Cryptography Pros

Confidentiality, Authentication of Origin, Authentication of Integrity

Asymmetric Cryptography Pros

Confidentiality, Authentication of Origin, Non-repudiation

Which of the following is/are enabled or provided by Cryptography?

Confidentiality, Authentication, Non-repudiation

___ is the process of attempting to defeat cryptographic systems.

Cryptanalysis

The transformation of meaningful data into something else is called ____.

Cryptography

Side-channel Analysis

Involves measuring some side-effect of the encryption/decryption to learn some or all the bits in the key.

Transposition

Is a fundamental type of operation that is performed in encryption or decryption. Involves rearranging the sequence of a set of values without altering each one. (other than its place in the sequence).

Substitution

Is a fundamental type of operation that is performed in encryption or decryption. Involves replacing a data value with another according to some rule.

Decryption

Is a process that converts ciphertext back into plaintext.

Encryption

Is a process that converts plaintext into meaningless data called ciphertext.

Codes

Is a system for representing data using a set of symbols.

Dictionary attack

Limits the set of keys to be tested to those likely to be chosen by typical users.

Which of the following uses both substitution and transposition operations? Decryption, Encryption, Product Cipher, Cryptoanalysis

Product Cipher

Which of the following is a transposition operation? Boolean operations, rotations, table lookup, variable replacement

Rotations

Symmetric Algorithms key size

moderate key length

Product Cipher

uses both substitution and transposition operations.

The cipertext produced depends on which of the following?

The plaintext, encryption process, and the key value.

The ciphertext produced during the encryption process depends on:

The plaintext, the encryption process, the key value.

Cryptography

The transformation of meaningful data into something else and vice versa.

___ involves rearranging the sequence of a set of values without altering each one .

Transposition

Brute force attack involves trying every possible key value to decrypt the intercepted ciphertext until the output seems to be valid plaintext. True or False?

True

Quantum Cryptography

Uses photons that represent 1's and 0's to transmit a key.

Quantum computing

Using a quantum computer to crack a cryptosystem.

Asymmetric Algorithms key size

Very long key length

Hybrid Solution

Where a one-time key value (called a session key) is encrypted asymmetrically with a recipients public key and a message is encrypted symmetrically with that key value.

Asymmetric Cryptography

The decryption process is NOT the equal and opposite of the encryption process, meaning it does NOT use the inverse operations in the reverse sequence of each cycle of decryption. There are 2 keys, a public and private key. One encrypts and the other decrypts.

Symmetric Cryptography

The decryption process is the equal and opposite of the encryption process, meaning it uses the inverse operations in the reverse sequence for each cycle of decryption. The same key is used in encryption and decryption.