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michalc /
Last active November 16, 2022 03:49
Decrypt KMS-encrypted SES emails in an S3 bucket
import base64
import json
import boto3
from cryptography.hazmat.primitives.ciphers.aead import AESGCM
s3 = boto3.resource('s3')
bucket = s3.Bucket('my-bucket')
kms_client = boto3.client('kms')
michalc /
Created January 3, 2022 16:37
Generating a Zip 2.0 file that's (just under) 8GiB
# Often it's claimed that a Zip 2.0 file cannot be bigger than 4GiB
# Here's how to make one that's just under 8GiB
from datetime import datetime
from stream_zip import stream_zip, ZIP_32
now =
perms = 0o600
def files():
for i in range(0, 0xffff):
class MyPipeline(_PipelineV2):
# Everything is a method so nothing happens on import time for flexibility (although possibly
# does a bit of discovery magic... need to think about that...)
# Everything is a _static_ method: nothing on self since things are run on different bits of hardware,
# and gets any run-time dependencies injected in
# _PipelineV2 won't actually have any code: other parts of the system will interrogate its
# subclasses as needed. For example
# - Code in Data Flow would construct a DAG
# - The test harness would the run this and upstream pipelines synchronously
michalc /
Last active September 13, 2021 05:27
Use libcrypto (OpenSSL) directly from Python with ctypes without compiling anything: AES decrypt with a little endian CTR counter
from contextlib import contextmanager
from ctypes import POINTER, cdll, c_char_p, c_void_p, c_int, create_string_buffer, byref
from sys import platform
# Uses a _little_ endian CTR counter, which OpenSSL doesn't directly support.
# Could be used to decrypt AES-encrypted ZIP files
def decrypt_aes_256_ctr_little_endian(
key, ciphertext_chunks,
get_libcrypto=lambda: cdll.LoadLibrary({'linux': '', 'darwin': 'libcrypto.dylib'}[platform])
michalc / postman-hawk.js
Last active September 21, 2021 05:44
Postman pre-request script for Hawk authentication in custom header
View postman-hawk.js
const hawkId = pm.variables.get('hawk_id');
const hawkKey = pm.variables.get('hawk_key');
const hawkHeader = pm.variables.get('hawk_header') || 'authorization';
const timestamp = parseInt(new Date().getTime() / 1000);
const nonce = CryptoJS.enc.Base64.stringify(CryptoJS.lib.WordArray.random(6));
michalc /
Last active December 31, 2022 10:20
Use libsqlite3 directly from Python with ctypes: without using the built-in sqlite3 Python package, and without compiling anything
# From, which is itself inspired by
from contextlib import contextmanager
from collections import namedtuple
from ctypes import cdll, byref, string_at, c_char_p, c_int, c_double, c_int64, c_void_p
from ctypes.util import find_library
from sys import platform
def query(db_file, sql, params=()):
michalc / spec.json
Last active July 4, 2021 20:15
World Bank + Vega-lite
View spec.json
"$schema": "",
"width": 630,
"height": 630,
"data": {
"values": [
"type": "Feature",
"id": 0,
"geometry": {
michalc /
Created March 7, 2019 09:19
Django + gevent + psycopg2 download whole PostgreSQL table as CSV
import csv
import logging
import gevent
from psycopg2 import (
from django.conf import (
michalc /
Last active December 2, 2018 19:51
Own implementation of getaddrinfo by calling libc directly from Python + ctypes, supporting IPv4 and IPv6 (experimental)
from ctypes import (
c_char_p, c_uint32, c_uint16, c_ubyte,
Structure, Union,
import platform
michalc /
Last active November 25, 2018 09:14
Path lock using a read/write/ancestor lock on each ancestor path
import asyncio
import contextlib
import weakref
from fifolock import FifoLock
class ReadAncestor(asyncio.Future):
def is_compatible(holds):
return not holds[Write]