Cybersecurity Cryptography

Diffie-Hellman

A cryptographic algorithm that combines both symmetric and asymmetric encryption to ensure confidentiality and integrity

Polybius Square

Also known as ______checkerboard. A device invented by ancient Greeks. Generally uses 5 rows and 5 columns. Words represented by numbered pairs

Cipher

An algorithm used to encrypt and decrypt text.

Digital signature

Asymmetric encryption that stamps the message using a private key. Allows recipient to know the message came from you

What did Alan Turing do /Alan turing

Cracked the Enigma code

RSA

Developed by Rivest, Shamir, & Adleman. Asymmetric encryption. The "s" in https indicates RSA encryption

Machine that's an example of symmetric encryption

Enigma machine

what did Tim Berners-Lee do /Tim Berners-Lee

Invented the World Wide Web

Morse Code

Invented using electricity to send a series of short and long changes in electrical current across long distances through wires

Disadvantages of symmetric encryption

Key space becomes massive, keeping all the keys secret

Asymmetric key encryption

Public key encryption method. Keys are large prime numbers

Disadvantages of asymmetric encryption

Relatively slow because of complex computations

Private encryption key

Sender and receive share a single private key. Also called shared key or symmetric key encryption. Same key is used in encryption and decryption

Elements needed for symmetric encryption

Shared key, message, encryption algorithm

Advantages of symmetric encryption

Simple (uses only 1 key), fast

Advantages of asymmetric encryption

Smaller key space, more secure because of private keys, can be used for encrypting and signing a message

Cryptography

The science and art of delivering a message securely and confidentially

Type of certificates supported by Kelopatra

X.509 (S/MIME) and openPGP

Encryption vs. Digital Signature

You encrypt a file using public key and decrypt using private key. You sign a document using private key and the receive uses the public key to verify

Pigpen Cipher

a geometric simple substitution cipher, which exchanges letters for symbols which are fragments of a grid

Vigenere Cipher

a method of encrypting text by applying a series of Caesar ciphers based on the letters of a keyword. A square arranged with letters of the alphabet

Mathematical one way function

a one way function is easy to do but hard to undo

Ceasar Cipher

a technique for encryption that shifts the alphabet by some number of characters

Plaintext

original message before it is encrypted

What did donald knuth do /donald knuth

prominent computer scientist, "father of the analysis of algorithms", author of "The Art of Programming" and important multi-volume encyclopedia of algorithms

Decryption

reverses the process of encryption to restore plaintext

Public key encryption

·Uses two keys, a public key available to everybody and a private key belonging to an owner

Digital certificate file

·contains a public key and metadata such as name, time of creation, key validity

How asymmetric encryption works

Uses both a public (encrypt) and private (decrypt) key

Examples of symmetric encryption

Vigenere, Enigma

Algorithm

A set of steps to accomplish a task. Can be expressed in many different notations. The way computers process data.

Railfence Cipher

A type of transposition cipher that encodes the message by splitting it over rows using a wave type pattern

Ciphertext

The encrypted message generated by a cipher

Steganography

The practice of concealing messages or information within other data such as text or images

What did john von neumann do /john von neumann

Virtually all contemporary computer designs are based on concepts developed by him. Computer instructions and data are stored in the same memory (___ ______ architecture)

The bombe machine

This machine was an electromechanical device used by British cryptologists to help decipher German Enigma-machine-encrypted secret messages during World War II

Symmetric key encryption (symmetric encryption)

Type of private key encryption method where sender and receiver share a single private key

Kleopatra

Used to develop and manage certificates