Chapter 8 Cryptography Flashcards
Cryptography
Pg.245
The science of altering information so that it cannot be decoded without a key.
Cipher
pg.245
a method used to encode characters to hide their value
Substitution Ciphers
pg.246
a type of coding or ciphering system that changes one character or symbol into another
Ceasar Cipher
pg.246
oldest known substitution ciphers known for shifting all letters a certain number
Vigenere cipher
pg.246
uses keyword to look up the cipher text in a table
Transposition cipher
pg.246
involves transposing or scrambling the letters in a certain manner
Rail Fence Cipher
pg.247
the message letters out diagonally over a number or rows and then read off cipher row by row
Enigma Machine
pg.248
essentially a typewriter that implemented a multi-alphabet substitution cipher
Steganography
pg.248
the process of hiding a message in a medium such as a digital image, audio file, or other file. Doing this prevents analyst from detecting the real message.
Symmetric algorithms
pg.249
requires both ends of an encrypted message to have the same key and processing algorithms
Symmetric key
pg.249
referred to a secret key or a private key, that is disclosed to people who aren’t authorized to use the encryption system
Block cipher
pg.250
The algorithm works on chunks of data- encrypting on eo and then moving to the next
Stream cipher
pg.250
the data is encrypted one bit or byte at a time
Data Encryption Standard
pg.250
used since the mid 70’s, it was primary standard used int he government and the industry until it was replaced by AES
Triple-DES
pg.250
technology upgrade of DES, still used even tho AES is preferred choice for government aplications
Advanced Encryption Standard
pg.50
has replaced DES as the current standard and uses the Rijnael algorithm
AES256
pg.250
uses 256 bits instead of 128. This qualifies for US government classification as Top Secret
Cast
pg.250
is an algorithm developed by Carlisle Adams and Stafford Tavares. still used in some products offered by MIcrosoft and IBM
Ron’s Cast
pg.250
is an encryption family produced by RSA labs. uses keys size of up to 2048 considered to be a strong system
Blowfish and Twofish
pg.251
an encryption system invented by a team led by Bruce Schneier that performs a 64-block cipher at very fast speeds. Twofish uses a 128 block
International Data Encryption Algorithm
pg.251
IDEA was developed by a Swiss consortium. Its an algorithmt hat uses a 128 bit key
One -time Pads
pg.251
are the only truly completely secure crptographic implementations. secure for two reasons. They use a key that is as long as a text message. That means there isnt a pattern in the key application for an attacker to use
Key Exchange
pg.251
in band key exchange and out of key exchange. In band essentially means that the key is exchanged in the same communications
