SignXML: XML Signature in Python

SignXML is an implementation of the W3C XML Signature standard in Python. This standard (also known as XMLDSig and RFC 3275) is used to provide payload security in SAML 2.0, among other uses. Three versions of the standard exist (Version 1 “Second Edition”, Version 1.1, and Version 2.0). SignXML implements all of the required components of the standard, and most recommended ones. Its features are:

Use of defusedxml.lxml to defend against common XML-based attacks when verifying signatures
Extensions to allow signing with and verifying X.509 certificate chains, including hostname/CN validation
Support for exclusive XML canonicalization with inclusive prefixes (InclusiveNamespaces PrefixList, required to verify signatures generated by some SAML implementations)
Modern Python compatibility (2.7-3.4+ and PyPy)
Well-supported, portable, reliable dependencies: lxml, defusedxml, cryptography, eight, pyOpenSSL
Comprehensive testing (including the XMLDSig interoperability suite) and continuous integration
Simple interface with useful defaults
Compactness, readability, and extensibility

Installation

pip install signxml

Note: SignXML depends on lxml and cryptography, which in turn depend on OpenSSL, LibXML, and Python tools to interface with them. You can install those as follows:

Ubuntu, Python 2:

apt-get install python-dev python-cffi libxml2-dev libxslt1-dev libssl-dev

Ubuntu, Python 3:

apt-get install python3-dev python3-cffi libxml2-dev libxslt1-dev libssl-dev

Ubuntu 12.04: python-cffi is not available on 12.04. Use apt-get install libffi-dev followed by pip install cffi.

OS X: Use Homebrew:

brew install libxml2 libxslt
brew link --force libxml2 libxslt

Synopsis

SignXML uses the ElementTree API (also supported by lxml) to work with XML data.

from signxml import xmldsig

cert = open("example.pem").read()
key = open("example.key").read()
root = ElementTree.fromstring(signature_data)
signed_root = xmldsig(root).sign(key=key, cert=cert)
verified_data = xmldsig(signed_root).verify()

Verifying SAML assertions

Assuming metadata.xml contains SAML metadata for the assertion source:

from lxml import etree
from base64 import b64decode
from signxml import xmldsig

with open("metadata.xml", "rb") as fh:
    cert = etree.parse(fh).find("//ds:X509Certificate").text

assertion_data = xmldsig(b64decode(assertion_body)).verify(x509_cert=cert)

XML signature methods: enveloped, detached, enveloping

The XML Signature specification defines three ways to compose a signature with the data being signed: enveloped, detached, and enveloping signature. Enveloped is the default method. To specify the type of signature that you want to generate, pass the method argument to sign():

signed_root = xmldsig(root).sign(method=signxml.methods.detached, key=key, cert=cert)
verified_data = xmldsig(signed_root).verify()

For detached signatures, the code above will use the Id or ID attribute of root to generate a relative URI (<Reference URI="#value"). You can also override the value of URI by passing a reference_uri argument to sign().

To verify a detached signature that refers to an external entity, pass a callable resolver in xmldsig.verify(uri_resolver=...).

See the API documentation for more.

Authors

Andrey Kislyuk

License

Licensed under the terms of the Apache License, Version 2.0.

https://img.shields.io/travis/kislyuk/signxml.svg

https://img.shields.io/coveralls/kislyuk/signxml.svg

https://img.shields.io/pypi/v/signxml.svg

https://img.shields.io/pypi/dm/signxml.svg

https://img.shields.io/pypi/l/signxml.svg

https://readthedocs.org/projects/signxml/badge/?version=latest

Metadata

Release files for signxml 0.4.6

For a detailed explanation of source distributions (sdists) and built distributions (wheels), please see the package formats documentation.

Source distribution (sdist)

Source distribution for signxml 0.4.6
File	Size	Uploaded
signxml-0.4.6.tar.gz	23.1 kB	Nov 28, 2015	Details

Built distribution (wheel)

Table of built distributions (wheels) for signxml 0.4.6
File	Interpreter	ABI	Platform	Reset
signxml-0.4.6-py2.py3-none-any.whl 22.4 kB Nov 28, 2015	Python 3, Python 2	none	any	Details

Total release size: 45.5 kB

Release files / signxml-0.4.6.tar.gz

Download URL	signxml-0.4.6.tar.gz
Size	23.1 kB
Tags	Source
SHA-256 checksum How to use checksums	`0b2f6b1aa47e52aa8cff226f64358930b0e454e84613c3e477bdd5533d23a171`
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Release files / signxml-0.4.6-py2.py3-none-any.whl

Download URL	signxml-0.4.6-py2.py3-none-any.whl
Size	22.4 kB
Tags	Python 2 Python 3
SHA-256 checksum How to use checksums	`cad68cc0e5f71b0c911a1065abf32beefed28b5d918ee45cb48a961fa129d19f`
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Upload date	Nov 28, 2015
Uploaded using Trusted Publishing? What is trusted publishing?	No

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signxml 0.4.6

SignXML: XML Signature in Python

Installation

Synopsis

Verifying SAML assertions

XML signature methods: enveloped, detached, enveloping

Authors

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Key dates

1 maintainer

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Project links

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1 maintainer

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Release files for signxml 0.4.6

Source distribution (sdist)

Built distribution (wheel)

Release files / signxml-0.4.6.tar.gz

Release files / signxml-0.4.6-py2.py3-none-any.whl

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