👀 Overview

1. Security Requirements
2. Cryptography and Cryptanalysis
3. Cryptographic Tools

🔖 words

• temper with : to change in a way that it should not to cause damage or harm
  정보손해의 우려가 있는 방식으로 바뀜

👊 Cryptographic Objectives

Threats	Goal	..
exposure of data	Confidentiality	- ability to keep information unavaliable and private to unathorized / cryptography is a tool to achieve confidentiality / not only content but also meta data(phonecall content <-> records) is important
tempering with data	Intergrity 무결성	ascertain that imformation has not been subject to addition·deletion·modification·undue delay / e.g. SHA, MAC / intentional or accidental data changes should be detectable
Impersonation	Authentication 인증	ascertain the indentity of others / e.g. digital signiture
사기..?오리발?	Non-Repudiation	prevent an authorized party from denying the existence or contes of a communication session (일이 일어났다는 사실을 부정하는거 막음) / e.g. Digital signature+notarization(from third party)
exposure of personal information	Privacy	어디까지 오픈할건지 degree to which entity(user, device) is willing to share info about itself / vs Auth. non-repudiation / the right of entity acting in its own behalf / e.g. encryption
Identification of individual	Anonymity	Being not identifiable within a set / diffrent with privacy (anonymity : action may be public, but actor's indentity remain privacy) / e.g. randomization, k-anonymity, I-diversity, TOR
Denial of service	Availability	prevent an unauthorized entity from making resources unavaliable / resource(computing, networking..) / e.g. prevent DoS attack / Cryptography isn't enough to deal with Dos Attack -> also other techniques(backup, redundancy, redirection ,,,)
Forbidden access	Authorization(Access control)	verify proper privileges to access resorce (접근권한) / authentication(e.g. ID) -> authentication / relate : Access control (IEE 802.1X, firewall...)

Cryptology

🛡Cryptography

• study of secret writing
• transform plaintext -> ciphertext by encryption (reverse : decryption)

🗡Cryptanalysis

• study of breaking ciphers
• determing ciphertext->plaintext