Hashlib and Cryptography

Introduction

Hashlib provides secure hashing algorithms for password storage and data integrity.

Hashing

import hashlib

# Basic hashing
data = "hello world"
h = hashlib.sha256(data.encode())
print(h.hexdigest())

# Multiple algorithms
h_md5 = hashlib.md5(data.encode())
h_sha1 = hashlib.sha1(data.encode())
h_sha512 = hashlib.sha512(data.encode())

Password Hashing

import bcrypt

# Hash password
password = "secure_password_123"
hashed = bcrypt.hashpw(password.encode(), bcrypt.gensalt())

# Verify password
bcrypt.checkpw(password.encode(), hashed)

HMAC

import hmac
import hashlib

key = b"secret_key"
message = b"message to authenticate"

sig = hmac.new(key, message, hashlib.sha256)
print(sig.hexdigest())

Practice Problems

1. Hash files for integrity checking
2. Implement password verification
3. Use HMAC for message authentication
4. Generate secure random tokens
5. Store and verify passwords safely