httpsig

Sign HTTP requests with secure signatures according to the IETF HTTP Signatures specification (Draft 8). This is a fork of the original module to fully support both RSA and HMAC schemes as well as unit test both schemes to prove they work. It's being used in production and is actively-developed.

See the original project, original Python module, original spec, and current IETF draft for more details on the signing scheme.

Requirements

• Python 2.7, 3.4-3.7
• PyCryptodome

Optional:

• requests

For testing:

• tox

• pyenv (optional, handy way to access multiple versions)

  $ for VERS in 2.7.15 3.4.9 3.5.6 3.6.7 3.7.1; do pyenv install -s $VERS; done

Usage

Real documentation is forthcoming, but for now this should get you started.

For simple raw signing:

import httpsig

secret = open('rsa_private.pem', 'rb').read()

sig_maker = httpsig.Signer(secret=secret, algorithm='rsa-sha256')
sig_maker.sign('hello world!')

For general use with web frameworks:

import httpsig

key_id = "Some Key ID"
secret = b'some big secret'

hs = httpsig.HeaderSigner(key_id, secret, algorithm="hmac-sha256", headers=['(request-target)', 'host', 'date'])
signed_headers_dict = hs.sign({"Date": "Tue, 01 Jan 2014 01:01:01 GMT", "Host": "example.com"}, method="GET", path="/api/1/object/1")

For use with requests:

import json
import requests
from httpsig.requests_auth import HTTPSignatureAuth

secret = open('rsa_private.pem', 'rb').read()

auth = HTTPSignatureAuth(key_id='Test', secret=secret)
z = requests.get('https://api.example.com/path/to/endpoint',
                         auth=auth, headers={'X-Api-Version': '~6.5'})

Class initialization parameters

Note that keys and secrets should be bytes objects. At attempt will be made to convert them, but if that fails then exceptions will be thrown.

httpsig.Signer(secret, algorithm='rsa-sha256')

secret, in the case of an RSA signature, is a string containing private RSA pem. In the case of HMAC, it is a secret password. algorithm is one of the six allowed signatures: rsa-sha1, rsa-sha256, rsa-sha512, hmac-sha1, hmac-sha256, hmac-sha512.

httpsig.requests_auth.HTTPSignatureAuth(key_id, secret, algorithm='rsa-sha256', headers=None)

key_id is the label by which the server system knows your RSA signature or password. headers is the list of HTTP headers that are concatenated and used as signing objects. By default it is the specification's minimum, the Date HTTP header. secret and algorithm are as above.

Tests

To run tests:

python setup.py test

or:

tox

Known Limitations

1. Multiple values for the same header are not supported. New headers with the same name will overwrite the previous header. It might be possible to replace the CaseInsensitiveDict with the collection that the email package uses for headers to overcome this limitation.
2. Keyfiles with passwords are not supported. There has been zero vocal demand for this so if you would like it, a PR would be a good way to get it in.
3. Draft 2 added support for ecdsa-sha256. This is available in PyCryptodome but has not been added to httpsig. PRs welcome.

License

Both this module and the original module are licensed under the MIT license.