StateofcryptoinPython A library created by people who make poor life choices.

HowDidWeGetHere

At Rackspace we work on an OpenStack, key management product named Barbican.

We needed to use crypto.

Cue the 80s working montage

WhatDoWeWant

Algorithm support Open Source MAINTAINED & Tested Python Support

Trust

WHyc? All major cryptographic libraries are currently implemented in a low level language,

mostly C or C++.

Reviewed Code Several C libraries have been sponsored through the review process for professional crypto review including various compliances that some customers care about.

Future possibilities There are some exciting options for future work in the crypto space with languages like Rust / Go. Unfortunately, these aren’t usable from Python right now.

Timing / Memory Attacks These attacks relate to exploiting timing differentials or securely wiping memory. They are difficult or impossible to remediate without the low level control exposed by C.

Existing Code Writing good crypto code is hard. Most existing libraries have a long history including significant bug-fixing / research.

StateofC OSS X-Platform Maintained Ubiquitous Std. Algorithms FIPS

OpenSSL

NSS

NaCl

Botan

CommonCrypto

MS CSP

Libgcrypt

LibreSSL

StateOfPython Backend Maintained Python Support Reviewed Completeness

m2crypto openssl recently active pypy with patch, no py3 no openssl swig

pycrypto bespoke* yes no pypy no no AEAD (without alpha)

pyopenssl openssl* yes yes (with crypto) no Thin openssl bindings

python-nss NSS low unknown no exposes some of NSS

botan botan yes py3, maybe pypy no exposes most of botan

Most of these libraries require / assume the user understands how to use the underlying C library correctly.

a new crypto library for Python

•  Support for PyPy and Python 3

•  Large, active team •  Encourages use of strong,

secure algorithms •  “Cryptography for humans”,

APIs

•  Support for modern algorithms such as AES-GCM and HKDF

•  Improved debug-ability and testability

•  Sane, secure API design (where possible)

cryptography

Grandiose Vision:

A cryptographic standard library for Python.

Python Cryptographic Authority

•  PyNaCl – Python bindings for the NaCL library •  cryptography – Python library to expose

cryptographic constructs •  service_identity – Service identity (hostname

verification) for PyOpenSSL. •  PyOpenSSL – Python bindings for OpenSSL •  bcrypt – Python wrapper for bcrypt library •  ed25519 – Pure Python implementation of one elliptic

curve signature scheme Logo courtesy of GitHub’s auto-generation.

PYCA

TheStructure

Bindings

Hazmat

Recipes

Backends

OpenSSL Our primary (and only guaranteed) backend. We don’t currently package OpenSSL to allow for flexibility for package maintainers.

Common Crypto Available on OS X and iOS, this is the preferred backend on OS X. Apple has decided not to ship newer version of OpenSSL, leaving developers with a old version lacking modern algorithms.

Cryptography is designed around the concept of backends. Each backend implements a set of defined interfaces. This allows us to implement a backend for each C library and exchange them transparently.

MULTIBACKEND This meta-backend allows composition and prioritization of multiple backends. This creates a superset of operations in Python, isolating the developer from variations in C libraries.

Moar! Any C backend can be included. We have spoken with many of the C library maintainers about writing a backend for cryptography.

Tests per run

Testify 73,813

575+ Million tests per week

78 Runs per build

5,757,414 Tests per build

15 Builds per day

45 Documentation runs per day

Alex Gaynor (Alex_gaynor) Paul Kehrer (reaperhulk) David Reid (dreid) Alex Stapleton (alexs)

ourPeople

5+ Commit Club aryx, skeuomorf, lvh, dstufft, cyli, exarkun, hynek, ashfall, juliankrause, wallrj, lvoz, phibos, chrisglass

+ 22 more contributors

currentSupport Symmetric Currently support a variety of common ciphers such as AES, Camellia, 3DES, CAST5, etc. Most non-patent encumbered block cipher modes are also supported.

hashing Support for common hashing algorithm like SHA1 / SHA2, RIPEMD160, Whirlpool and MD5, including HMAC support for all supported hashes. Support for KDFs and TOTP.

Asymmetric Support Supports RSA, DSA and elliptic curve for signing, verification, encryption and decryption (for RSA). PKCS #1 and #8 key loading done now.

fernet A high level recipe designed to provide easy to use authenticated encryption.

Tl;dr Authenticated Encryption at rest, Public key signatures & encryption, Hashing, HMAC, Key derivation, two-factor (OTP)

DownstreamConsumers PyOpenssl Current based on cryptography. Pure python package, gained support for PyPy and Py3

Pycrypto Currently in prototype / investigation phase.

Paramiko Work in progress PR for rebasing.

Conch Interest expressed in switching. Someone interested in writing a patch?

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Cryptography PyPI download counts

DualLicensing Project Licensing Cryptography is licensed using Apache 2 and two-clause BSD (in-progress).

Backend Licensing Set by the backend author, can accommodate any license structure.

•  Van Lindberg

•  Chairman of the Python Software Foundation

•  Wrote “Intellectual Property and Open Source”

•  Rackspace IP Head Honcho

if you don’t like it, blame van

LetsReview

Algorithm support Open Source MAINTAINED & Tested Python Support

Multi-Backend

& Openssl

Apache 2 &

BSD

575+ Million Tests

40+ contributors

2.6, 2.7, 3.2, 3.3, 3.4,

& pypy

FutureWork X509 Support for parsing all extension and object types defined in RFC3280 and RFC5280.

TLS TLS 1.2 support, modern cipher suites, stripe open source grant winner working on TLS for cryptography.

Less Common Primitives Chacha20, Salsa20, non-NIST elliptic curves.

Multiple backend support Allows for backends to live in separate packages and be used by cryptography at runtime.

Github github.com/pyca/cryptography

Website

cryptography.io

Install

pip install cryptography

~ fin ~