http-message-signatures 0.1.0

An implementation of the IETF HTTP Message Signatures draft standard

http-message-signatures is an implementation of the IETF HTTP Message Signatures draft standard in Python.

Installation

pip3 install http-message-signatures

Synopsis

from http_message_signatures import HTTPMessageSigner, HTTPMessageVerifier, HTTPSignatureKeyResolver, algorithms
import requests, base64, hashlib, http_sfv

class MyHTTPSignatureKeyResolver(HTTPSignatureKeyResolver):
    keys = {"my-key": b"top-secret-key"}

    def resolve_public_key(self, key_id: str):
        return self.keys[key_id]

    def resolve_private_key(self, key_id: str):
        return self.keys[key_id]

request = requests.Request('POST', 'https://example.com/foo?param=Value&Pet=dog', json={"hello": "world"})
request = request.prepare()
request.headers["Content-Digest"] = str(http_sfv.Dictionary({"sha-256": hashlib.sha256(request.body).digest()}))

signer = HTTPMessageSigner(signature_algorithm=algorithms.HMAC_SHA256, key_resolver=MyHTTPSignatureKeyResolver())
signer.sign(request, key_id="my-key", covered_component_ids=("@method", "@authority", "@target-uri", "content-digest"))

verifier = HTTPMessageVerifier(signature_algorithm=algorithms.HMAC_SHA256, key_resolver=MyHTTPSignatureKeyResolver())
verifier.verify(request)

Note that verifying the body content-digest is not yet implemented, so it remains the caller’s responsibility.

See what is signed

It is important to understand and follow the best practice rule of “See what is signed” when verifying HTTP message signatures. The gist of this rule is: if your application neglects to verify that the information it trusts is what was actually signed, the attacker can supply a valid signature but point you to malicious data that wasn’t signed by that signature. Failure to follow this rule can lead to vulnerability against signature wrapping and substitution attacks.

In http-message-signatures, you can ensure that the information signed is what you expect to be signed by only trusting the data returned by the verify() method:

FIXME: example

Authors

• Andrey Kislyuk

Links

• Project home page (GitHub)

• Documentation

• Package distribution (PyPI)

• Change log

• IETF HTTP Message Signatures standard tracker

• OWASP Top Ten

Bugs

Please report bugs, issues, feature requests, etc. on GitHub.

License

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