Cybersecurity 20-23

cryptography

scrambling data so that it looks like babble to anyone except those who know the trick to decoding it.

Algorithim (aka cipher)

a precise set of instructions that tells programs how to scramble and unscramble data.

Plaintext

decrypted or unencrypted data

ciphertext

data that has been encypted

cyryptanalysis

attempting to break a cryptographic system and return the encrypted message to plaintext.

Encryption with substitution

replacement of a character with different charactermo

monoalphabetic ciphers

same letter is used as a substitute every time. like a is used for z for the entire chapter.

what is transposition

changing the order of items.

ceasar cipher

shift cipher

OTP- one time pad

encryption method in which the pre-shared key is used only once. Capturing or stealing key is useless since it will not be used again to encrypt.

Encryption

security technique that involves converting information or data into a code to prevent unauthorized access or understanding.

How does encryption work?

original data, (plaintext), is transformed into an unreadable format called cipher text using algorithms and encryption keys.

What is the primary purpose of encryption?

ensure teh confidentiality and privacy of information, protecting it from unauthorized disclosure or tampering. used in applications, like securing communication over the internet, protecting sensitive files and data on storage devices, ensuring privacy.

What is Full-Disk encryption?

provides comprehensive encryption by encrypting the entire storage device and securing all data stored on it.

What is partitioning?

offers selective protection by encrypting specific partitions on a storage device.

What is File encryption?

focuses on independently securing individual files, ensuring their confidentiality.

What is volume encryption

akin to partition encryption, but used in different contexts or technologies.

Database encryption

secures data within a database, shielding sensitive information from unauthorized access.

What is Record encryption?

narrows its focus to encrypting specific records or entries within a database.

What is transport or communication encryption?

plays crucial role in securing data during transmission, preventing unauthorized interception or access. Each layer contributes to overall tapestry of encryption.

What is asymmetric encryption

operates through a pair of keys, public and private, where data encrypted with one key can only be decrypted by its counterpart.

What is symmetric encryption?

employs a single key for both encryption and decryption.

What is Key Exchange.

critical element in encryption, involves the secure transmission of cryptographic keys between parties, enabling a foundation for secure communication.

Algorithims.

play a pivotal role in guiding the mathematical procedures for both encryption and decryption processes. Architects of the intricate dance that transforms plaintext into cipher text and then plaintext again.

The effectiveness of encryption is influenced by

key length, typically measured in bits. Longer keys makes for better security.

What is AES?

Advanced encryption Standard.

What is RSA?

Rivest-Shamir-Adleman

What is DES

Data Encryption Standard.

What is transposition?

When you order the letters into 6 columns.

What is a Vingenere Cipher

Po

What are the pros and cons of symmetric encryption?

Doesnt scale very well, challenging to distribute, but its very fast to use with less overhead than asymmetric encryption. It is often combined with asymmetric encryption.

Asymmetric encryption is also known as

public key cryptography

What is ECC

Elliptic curve cryptography. instead of using prime numbers, use curves.

How long are modern keys

128 bits or more. Some are combinations of different values to produce even larger numbers.

What is key stretching

used to convert a password to a longer and more random one.

What is hashing?

one way algorithm that converts data into a unique string of text known as a digest. Data cannot be recovered.

What is hashing used with

integrity checks, digital signatures, authentication, security apps, cryptocurrencies

What is a collision

when different inputs result in the same output hash. They are very rare and only found with early versions of hashing algorithms. such as MD5 and SHA-1

What is Salting?

to further increase the strength of passwords, salting is an addition of a random string of text to the password prior to hashing. The salt value is then stored with the has.

To verify a downloaded file,

websites provide the hash of the original file and if the provided hash matches the calculated then the file is unaltered. Digital signatures also provide proof a message has been unaltered.

What is a mode of Operation

algorithms used with a block cipher to make an encryption algorithm. Th

There are two forms of authenticated modes of operation

single sided which means one side validates like visiting a website with valid x.509 certificate. or mutual relies on a similar validation process but on both sides.

What is counter mode

CTR which changes block ciphers to stream ciphers by generating successive blocks using a non repeating counter.

What is a block chain?

A distributed and indisputable public ledger that stores records in a way allows distribution without tampering. Each record, called a block, is link via cryptography and contains a hash of teh previous blocks, timestamps, and transaction data. Repeated hashing makes it resistant to data alteration.

What is cryptograpghy?

“secret” “to hide” the practice and study of writing or solving codes.

Cryptoanalysis?

The art/study of solving and cracking encryptions without being told the key. Every time a new security tool is invented, attackers begin searching for weaknesses in the tool.

What are the uses of hashing in cryptography?

message integrity checks, digital signatures, authentication, information security applications, and cryptocurrencies.

Different secure hashing algorithms.

MD5, SHA256, SHA512

Story abt collisions

Xiaoyun Wang and Hong Yu in china demonstrated a collision in the MD5 proving collisions can exist in widely used hashing algorithms. It was determined that SHA-1 can have collisions. Since then it’s been broken. SHA2 and 3 and so on.

what is an x.509 certificate

the browser validates or invalidates the certificate and then you can navigate the site. Mutual authentication relies on these certificates both ways. irf

first digital cryptocurrency that was created to be used on the block chain.

bitcoin

Three components contained in a block when referring to the blockchain?

Data, hash, and hash of previous block

A hash is like a fingerprint

each one has its own unique qualities and characteristics

What is Public Key Infastructure

PKI- a framework that manages digital keys and certificates, ensuring secure communication and authentication in a networked environment.

What are teh three important components of PKI

public keys, private keys, escrow.

What is a public key?

a part of an asymmetric encryption system. The key is shared openly and used to encrypt data. It cannot decrypt. Only the corresponding private key can do that.

What is the private key?

The counterpart of the public key. It’s kept secret and used for decrypting data that was encrypted with a public key.

What is Key escrow.

when a trusted third party holds a copy of a user’s private key. It’s a precautionary measure in case the user loses access to their key. It can be released to law enforcement if necessary.

PKI is crucial for

secure communication, digital signatures, ensuring integrity and authenticity of data in online transactions, it provides framework for managing, distributing, and revoking digital certificates that authenticate identities of users and devices in a network.