chap4 Flashcards
is the science of making and breaking secret codes.
Cryptology
Modern cryptography uses computationally secure algorithms
tru
The history of cryptography started in
diplomatic circles thousands of years ago
Each encryption method uses a specific algorithm, called a
cipher
is a series of well-defined steps used to encrypt and
decrypt messages.
cipher
There are several methods of creating ciphertext
▪ Transposition
▪ Substitution
▪ One-time pad
The roots of cryptography are
found in
Egyptian and Roman
civilizations.
The first known evidence of
cryptography can be traced to the
use of
hieroglyph
The earlier Roman method of cryptography, popularly known as the
Caesar
Shift Cipher.
Two Types of Encryption
Symmetric algorithms
ASymmetric algorithms
15th century gave birth to
Vigenère Coding
These algorithms use the same pre-shared key
Symmetric algorithms
use one key to
encrypt data and a different key to decrypt data.
▪ Asymmetric algorithms
a symmetric block
cipher with 64-bit block size
Digital Encryption Standard
64 blocks
128 keys.
International Data Encryption Algorithm
fixed 128
Advanced Encryption Standard
uses the product of two very large prime
numbers
Rivest_Shamir-Adleman
provides an electronic exchange
Diffie-Hellman -
uses the U.S. government standard for digital signatures.
ElGamal
uses elliptic curves
Elliptic Curve Cryptography
Difference between symmetric and asymmetric
Symmetric more
efficient and can handle more data.
Asymmetric more efficient at protecting the confidentiality of
small amounts of data
application of cryptohraphy
one-time password-generating token
▪ Internet Key Exchange
Secure Socket Layer
Secure Shell
a private network that uses a public network
VPN
services allow for authentication, integrity
ipsec
