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Introduction to Cryptography - C839... ECES v2- 359 Q & A
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Introduction to Cryptography - C839...ECES v2- 359 Q & A
Cryptography - -The process or skill of communicating in or deciphering
secret writings
-What is a key component of any secure communications. - -Cryptography
-A way to encode a message that would be readable by intended recipients.
- -Cryptography
-algorithms that substitute one character of cipher text for each character of
plain text. - -Mono-Alphabet Substitution
-What type of cryptographic algorithm is a Caesar Cipher? - -Mono-Alphabet
Substitution
-What type of cryptographic algorithm is the Atbash Cipher? - -Mono-
Alphabet Substitution
-What type of cryptographic algorithm is the Affine Cipher? - -Mono-
Alphabet Substitution
-What type of cryptographic algorithm is the Rot13 Cipher? - -Mono-
Alphabet Substitution
-One of the oldest encryption methods - -Caesar Cipher
-Encryption method purported to have been used by the ancient romans/ - -
Caesar Cipher
-What is the key size for the Advanced Encryption Standard (AES)? - -128-
bit
-A Hebrew code which substitutes the first letter of the alphabet for the last
and the second letter for the second to the last, etc. It simply reverses the
alphabet - -Atbash Cipher
-A single substitution cipher that simply reverses the alphabet. - -Atbash
Cipher
-Any single-substitution alphabet cipher in which each letter in the
alaphabet is mapped to some numeric value, permuted with some relatively
simple mathematical function, then converted back. - -Affine Cipher
, -A cipher where each letter is converted to a number, shifted by some
about, and then converted back to a letter. - -Caesar Cipher
-ax + b (mod M) - -The basic formula for an affine cipher
-A permutation of the Caesar cipher. All characters are rotated 13 charcters
through the alphabet. - -ROT13 Cipher
-A physical cylinder that was used to encrypt messages. Turning the cylinder
produced different cipher texts. - -Scytale Cipher.
-What type of cryptographic algorithm is the Cipher Disk? - -Multi-Alphabet
Substitution
-What type of cryptographic algorithm is the Vigenère Cipher? - -Multi-
Alphabet Substitution
-What type of cryptographic algorithm is the Enigma Machine? - -Multi-
Alphabet Substitution
-Invented by Leon Alberti in 1466 - -Cipher Disk
-Poly-alphabetic, each time turn of the disk produced a new cipher - -Cipher
Disk
-Literally a disk that was turned to encrypt plain text - -Cipher Disk
-Perhaps the most widely known poly-alphabet cipher - -Vigenère Cipher
-Invented in 1553 by Giovan Battista Bellaso - -Vigenère Cipher
-A method of encrypting alphabetic text by using a series of different mono-
alphabet ciphers selected based on the letters of a keyword - -Vigenère
Cipher
-The first person to publish a successful general attack on the Vigenère
cipher - -Friedrich Kasiski
-Invented in 1854 by Charles Wheatstone - -Playfair Cipher
-Encrypts two letters rather than one, and uses a 5 by 5 table containing a
key word or phrase. - -Playfair Cipher
-First cipher used by the German Army during World War I - -ADFGX Cipher
, -Invented by Colonel Fritz Nebel in 1918. - -ADFGX Cipher
-A transposition ciphers which used: A modified Polybius square A single
columnar transposition A 36 letter alphab - -ADFGX Cipher
-One of the earlier attempts to make substitution ciphers more robust by
masking the letter frequencies. - -Homophonic Substitution
-Plain text letters map to more than one cipher text symbol. - -Homophonic
Substitution
-Essentially the message is hidden in unrelated text. So you might send a
message such as: "We are having breakfast at noon at the café. Would that
be okay?" - -Null Cipher
-The sender and recipienthave prearranged to use some pattern, taking
certain letters from the message. - -Null Cipher
-Both parties agree to use a particular book as the basis of this cipher. - -
Book Cipher
-The most widely known transposition cipher. - -Rail Fence
-You take the message you want to encrypt and alter each letter on a
different row. Write down the text reading from left to right. - -Rail Fence
Cipher
-An electromechanical rotor based cipher system. - -The Enigma Machine
-What type of cipher was The Enigma Machine? - -Multi-Alphabet
Substitution
-Allows you to enter in any text, choose the historic algorithm you wish to
use, then encrypt that text in a matter of seconds. - -CrypTool
-The same key is used to encrypt the message and to decrypt it. - -
Symmetric Cryptography
-Changes to one character in the plain text affect multiple characters in the
cipher text. - -Diffusion
-Attempts to make the relationship between the statistical frequencies of
the cipher text and the actual key as complex as possible. - -Confusion
-A small change yields large effects in the output, like an avalanche. - -
Avalanche
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