Crypto - 101

Pre-requisites

• Python
• pip install bcrypt pynacl cryptography

ALWAYS USE LIBSODIUM/NACL

Never roll your own crypto. (unless you want to learn how things work) Avoid messing with primitives or libs that require args that you don't understand.

Our Characters

• Alice
• Bob
• Eve

Alice wants to communicate with Bob. Eve (the eavesdropper) can listen to what they "say".

Types of encryption

https://ico.org.uk/for-organisations/guide-to-data-protection/encryption/types-of-encryption/

Symmetric

Alice and Bob know the key to encrypt their data. The key doesn't change and has been shared out of band (e.g. verbally at the pub)

AES

Assymetric

Alice and Bob don't have a key to encrypt their data.

Hashing

Not all hash functions are created the same.

Above all NaCL (libsodium)

A bunch of godlike cryptographers made a lib, humans made bindings to these libs. Use them. https://download.libsodium.org/doc/bindings_for_other_languages/

# The connection to this site is encrypted and authenticated using TLS 1.2 (a strong protocol),

ECDHE_RSA with X25519 (a strong key exchange), and AES_128_GCM (a strong cipher).

let's talk certs and openssl