3 - 1: Encryption Flashcards
What is cryptography?
The use of mathematical algorithms to transform information into an encrypted form not readable by others
What two functions comprise cryptography?
Encryption - converts plaintext to ciphertext, Decryption - conversion from ciphertext back to plaintext
What are algorithms
Mathematical instructions, similar to a recipe
Decryption relies on what two inputs?
1) Ciphertext and 2) decryption key
Symmetric Encryption algorithms
Encryption and decryption both use the same key (shared secret)
Asymmetric Encryption algorithms
Encryption and decryption have different keys, which are paired (public key)
Formula to compute the amount of symmetric keys needed
n(n - 1) / 2 , where n is the amount of people who wish to communicate
What keys would you have in an Asymmetric algorithm?
Public key given to partners, and private key kept secret
To encrypt or decrypt from asymmetric cryptography, remember to use keys that are:
from the same pair
Although slower, asymmetric cryptography provides what benefit?
Requires far fewer keys in organizations
What are the 5 goals of cryptography?
Confidentiality, Integrity, Authentication, Obfuscation, Non-repudiation
Codes
A system that substitutes one word or meaningful phrase for another to provide secrecy and/or efficiency
Ciphers
A system of mathematical algorithms to encrypt and decrypt messages
Stream ciphers
Operate on one character or bit of a message at a time
Block ciphers
Operate on a chunk of characters at a time
