Software Security - Week 10

Flashcards covering key concepts from the lecture notes on Software Security and Data Privacy.

Encryption

The process of converting data into an unreadable format, accessible only with authorization.

Decryption

The process of converting encrypted data back into its original, readable format.

Symmetric Key Encryption

A type of encryption that uses a single key for both encryption and decryption.

Asymmetric Key Encryption

A type of encryption that uses a pair of keys—one for encryption and another for decryption.

Encryption Algorithm

Performs substitution and transposition on plaintext, taking plaintext and a key as input to produce ciphertext.

Secret Key

Input to the encryption algorithm, independent of the plaintext and the algorithm itself.

Ciphertext

Scrambled message produced as the output of the encryption algorithm.

Decryption Algorithm

Reverses the encryption algorithm to transform ciphertext back into plaintext, using the key.

Substitution

Letters of plaintext are replaced by other letters, numbers, or symbols.

Transposition

The position of letters or bits within the plaintext are changed.

Caesar Cipher

Each letter in the plaintext is replaced by a letter a fixed number of positions down the alphabet.

Plaintext

Simple message written by the user before encryption.

Ciphertext

Encrypted message after applying encryption techniques to the plaintext.

Playfair Cipher

Multiple-letter encryption technique using a 5x5 matrix of letters constructed with a keyword.

Railfence

A transposition technique where plaintext is written down as a sequence of diagonals and read off as rows.

Public-key cryptosystems

Algorithms based on mathematical functions, using two separate keys for encryption and decryption.

Public-Key Cryptosystem

An encryption system that uses a public key for encryption and a private key for decryption.

RSA

First algorithm to meet the requirements of a public-key cryptosystem, using integers between 0 and n-1.

Diffie-Hellman Key Exchange

A key exchange protocol that allows two parties to securely share a secret key over a public network.

Primitive Root

A number whose powers modulo p generate all the integers from 1 to p-1, where p is a prime number.