notes.txt

These are my personal notes that I made while learning the concepts for this project. 
You can read it but you might not understand some things :)

Encryption:
- hiding the real thing by converting it into gibberish.
- cannot be converted back without key.

Types:

- symmetric
    - uses same key for both encryption and decryption
    - fast
    - if key leaked: anyone can decrypt

- asymmetric
    - public key - for encrypting
    - private key - for decrypting
    - used in secure communication of internet (SSL/TLS, email encryption)
    - slow

only symmetric is used in this project

encryption - plaintext to ciphertext using specific algo and key
decryption - ciphertext to og plaintext using correct key

ex. we interact with ciphertext daily through secure websites (HTTPS), secure messaging apps & password managers :)

ciphertext - can be any form of data and looks like a jumble of random letters, numbers or symbols or even as binary code.

symmetric encryption workflow:
- secret key is generated  - random bytes
- plaintext (normal data) is turned into ciphertext (enc data) using a key
- same key is used to decrypt

Hashing vs Encryption:

- Encryption:
    - two way (encrpt - decrypt)
    - store data securely (recoverable)
    ex -  storing encrpyted passwors

- Decryptions:
    - one way (only hash)
    - store passwords (non recoverable)
    ex - storing password hash for login verification

Fernet:
it is a symmetric encryption system which is found in python's cryptography library.
internally it uses AES

- features:
    - random IV (intialization vector) is used - every enc is unique
    - MAC (message auth code) is added - checks if data is tempered
    - expiry time is opt (tokens can expire)

Key:
random secret bytes value used in both encrption and decryption
- same key for btoh enc and dec
- if key lost - data can never be dec
- if key leaked - anyone can dec

Bytes vs Strings:
Encryption algos bytes me kaam karte hai, not in Strings
so always have to convert

- Python
    string -> bytes : .encode()
    bytes -> string : .decode()

Base64 encoding:
ciphertext usually is in binary, storing it in database or json directly is unsafe
that is why converting it to base64 is good, we get safe printable chars

base64 != encryption
this is only encoding method (converting to readable format)

Database storage:
2 ways to store data

- BLOB
    binary large object - raw bytes can be stored

- TEXT
    enc data ko base64 string bana kar store karna

- best idea:
    encrypt - base64 encode - store as TEXT

Key preservation:
if key is lost in fernet - the enc data is forever lost
because symmetric enc is only reversible if you have the key