I think easier desk Flashcards
(214 cards)
Invented by the Hebrew. Single substitution monoalphabetic cipher that substitutes each letter with it’s reverse (a and z, b and y, etc).
Atbash Cipher
Monoalphabetic cipher where letters are shifted one or more letters in either direction.
Caesar Cipher
Monoalphabetic cipher that shifts characters 13 characters. A would become N, B would become O, etc.
ROT 13. Stands for Rotate 13.
Was a staff with papyrus or letter wrapped around it so edges would line up. There would be a stream of characters which would show you your message. When unwound it would be a random string of characters. Would need an identical size staff on other end for other individuals to decode message.
Scytale Cipher
Doing something like +1, -2, +3 and shifting each character a different amount to the left or right. For example, doing +1, -2, +3 with dog would results in emj.
Multi-Alphabet Substitution Cipher
A disk you rotated to encrypt/decrypt. Similar technologies were used in the Enigma machine.
Cipher Disks
Created by Leon Alberti. Considered the forefather of modern encryption.
Cipher Disks
Invented by Giovan Battista Bellaso in middle 1553.
Vigenere Cipher. Vigenere created a stronger version of the cipher.
Combining/Weaving Caesar cipher. Not cracked until late 1800s. It is a cipher square with A to Z across all the columns and rows. You then use a keyword to encrypt the message. For example, if the message is cat, and the keyword is horse, you would look up where c and h intersect on the table (which is j), then where a and o intersect (o) and t and r (k). Cat would then be encrypted as jok.
Vigenere Cipher
Uses a 5x5 table and a key word. Rest of the alphabet is placed on table in alphabetic order, skipping letters used in the keyword. You break up the message into two character chunks and return a single character value. If the letters appear on the same row of your table, replace them with the letters to the right. If it is on the same column, replace them with the letters below.
Playfair Cipher
Invented by Charles Wheatstone in mid 1800s.
Playfair Cipher. Lord Playfair pushed use of it.
Invented by Colonel Fritz Nebel in 1918.
ADFGVX Cipher
It is a 6x6 grid with ______ at the top of each column and beginning of each row. The 26 letters and numbers 0-10 are placed randomly on the table. You then replace each character of your message with two characters which are represented by the column followed by the row each character is present in.
ADFGVX Cipher
Invented between World Wars, used by Germans and Japanese.
Enigma Machine
Data could be transmitted both via radio or printed on paper. Designed so that when a key was pressed, the cipher text for that plain text was different each time. Was a multi-alphabet cipher with 26 possible alphabets.
Enigma Machine
We can expose everything but the private key and the data can still be secure.
Kerckhoff’s Principle
Issue with Symmetric Encryption
There’s only one key, and it’s difficult to only have both parties who need the key to have it.
Base 2 system instead of base 10 system.
Binary Math
If both numbers have a one in the same place, then the resultant number is a one. If not then it is a zero
1st number - 1100
2nd number - 0100
————————–
Result - 0100
Binary AND
Checks to see if there is a one in either or both numbers in the same place. If so, the resultant number is one, if not, it is zero.
1st number - 1100
2nd number - 0100
————————–
Result - 1100
Binary OR
Checks to see if there is a one in either number in the same place. If so, the resultant number is one, if not, it is zero.
1st number - 1100
2nd number - 0100
————————–
Result - 1000
Binary XOR (Exclusive OR) ⊕
XORing the plain text with the key.
Substitution
Swapping blocks of text.
Transposition
Making the relationship between a key and the ciphertext as complex as possible.
Confusion