Auth & security at scale
OAuth2, JWT, IAM patterns, secrets rotation, and least-privilege service auth.
How to mock Argon2 password hashing in Python
This code demonstrates a mock Argon2 password hasher using HMAC-SHA256 iterations, providing hash and verify methods that mimic Argon2's salted, iterated derivation.
import hashlib
import hmac
import os
class Argon2Mock:
def __init__(self, salt_size=16, hash_len=32):
self.salt_size = salt_size
self.hash_len = hash_len
def hash(self, password: str, salt: bytes = None) -> str:
if salt is None:
salt = os.urandom(self.salt_size)
…How to mock DNS CAA record lookups in Python
Parse and filter DNS CAA records with a mock lookup function, demonstrating how certificate authorities validate domain authorization.
import dnslib
def parse_caa_record(record_string):
"""Parse a DNS CAA record string into its components."""
parts = record_string.split()
flags = int(parts[0])
tag = parts[1]
value = parts[2]
return flags, tag, value
def mock_caa_lookup(domain, caa_records):
"""Mock DNS CAA lookup that re…How to redact secrets from log messages in Python
This code defines a logging.Filter subclass that automatically redacts sensitive keys like password, token, and API key from any dict logged.
import logging
from dataclasses import dataclass
@dataclass
class ApiResponse:
status: int
body: dict
class SecretRedactor(logging.Filter):
SENSITIVE_KEYS = {"password", "token", "secret", "api_key"}
def filter(self, record: logging.LogRecord) -> bool:
if isinstance(record.msg, dict):
…How to sign and verify JWT RS256 in Python
Generate RSA keys, create a JWT signed with RS256, verify its signature, and decode the payload using the cryptography library.
import json
import time
import base64
import hmac
import hashlib
from cryptography.hazmat.primitives.asymmetric import rsa
from cryptography.hazmat.primitives import serialization, hashes
from cryptography.hazmat.primitives.asymmetric import padding
from cryptography.hazmat.primitives.asymmetric.utils import encode_ds…Implement RSA OAEP Padding in Python
Implements OAEP-style padding with MGF1 using SHA-256 from the Python standard library for RSA encryption prep.
import os
import hashlib
def mgf1(seed, length, hash_func=hashlib.sha256):
"""MGF1 mask generation function."""
output = b""
counter = 0
while len(output) < length:
c = counter.to_bytes(4, "big")
output += hash_func(seed + c).digest()
counter += 1
return output[:length]
…Mock client credentials machine auth in Python
This code simulates the OAuth2 client-credentials flow for service-to-service calls, generating a mock bearer token with expiry and caching, plus a revoke method, using only the standard library.
import time
import hashlib
import secrets
class MachineAuth:
"""Mock client-credentials machine auth for service-to-service calls."""
def __init__(self, client_id, client_secret):
self.client_id = client_id
self.client_secret = client_secret
self._token = None
self._expire…OAuth2 authorization code flow mock in Python
A minimal HTTP server that mocks the OAuth2 authorization code flow, issuing codes via /authorize and exchanging them for tokens at /token.
import json
from http.server import BaseHTTPRequestHandler, HTTPServer
from urllib.parse import urlparse, parse_qs
AUTH_CODE_STORE = {}
CLIENT_ID = "demo-client"
REDIRECT_URI = "http://localhost:8000/callback"
class OAuthHandler(BaseHTTPRequestHandler):
def do_GET(self):
parsed = urlparse(self.path)
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Auth & security at scale — Python code examples
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