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HTTP Request Signing with ✨ STANDARDS ✨

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httpsig

Standards-based HTTP request signing and verification for Go

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Introduction

httpsig provides support for signing and verifying HTTP requests according to the HTTP Message Signatures draft standard. This standard focuses on signing headers and request paths, and you probably want to sign the request body too, so body digest calculation according to Digest Headers is included.

Signed HTTP requests are ideal for scenarios like sending webhooks, allowing recievers to securely verify the request came from your server, mitigate replay attacks, etc.

Contrary to the commonly-used x-hub-signature, The standards implemented by this package provide a signature of the entire request, including HTTP headers and the request path.

Usage

Signing HTTP Requests in Clients

To sign HTTP requests from a client, wrap an http.Client's transport with NewSignTransport:

client := http.Client{
	// Wrap the transport:
	Transport: httpsig.NewSignTransport(http.DefaultTransport,
		httpsig.WithSignEcdsaP256Sha256("key1", privKey)),
}

var buf bytes.Buffer

// construct body, etc
// ...

resp, err := client.Post("https://some-url.com", "application/json", &buf)
if err != nil {
	return
}
defer resp.Body.Close()

// ...

Verifying HTTP Requests in Servers

To verify HTTP requests on the server, wrap the http.Handlers you wish to protect with NewVerifyMiddleware. NewVerifyMiddleware returns the wrapping func, so you can reuse configuration across multiple handlers.

h := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Content-Type", "text/plain")
	io.WriteString(w, "Your request has an valid signature!")
})

middleware := httpsig.NewVerifyMiddleware(httpsig.WithVerifyEcdsaP256Sha256("key1", pubkey))
http.Handle("/", middleware(h))

For more usage examples and documentation, see the godoc refernce

The Big Feature Matrix

This implementation is based on version 06 of HTTP Message Signatures (draft-ietf-htttpbis-message-signatures-05 from 8 June 2021). Digest computation is based on version 05 of Digest Headers (draft-ietf-httpbis-digest-headers-05 from 13 April 2021).

Feature Notes
sign requests
verify requests
sign responses
verify responses
add expires to signature sorely needed
enforce expires in verify
@method component
@authority component
@scheme component
@target-uri component
@request-target component Semantics changed in draft-06, no longer recommented for use.
@path component
@query component Encoding handling is missing.
@query-params component
@status component
request-response binding
Accept-Signature header
create multiple signatures
verify from multiple signatures
rsa-pss-sha512
rsa-v1_5-sha256
hmac-sha256
ecdsa-p256-sha256
custom signature formats eddsa is not part of the spec, so custom support here would be nice!
JSON Web Signatures JWS doesn't support any additional algs, but it is part of the spec
Signature-Input as trailer Trailers can be dropped. accept for verification only.
Signature as trailer Trailers can be dropped. accept for verification only.
request digests
response digests Tricky to support for signature use according to the spec
multiple digests
digest: sha-256
digest: sha-512
digest: md5 Deprecated in the spec. Unlikely to be supported.
digest: sha Deprecated in the spec. Unlikely to be supported.
digest: unixsum
digest: unixcksum
digest: id-sha-512
digest: id-sha-256 id-* digests are more resilient for content-encoding support
custom digest formats

Contributing

I would love your help!

httpsig is still a work in progress. You can help by:

  • Opening a pull request to resolve an open issue.
  • Adding a feature or enhancement of your own! If it might be big, please open an issue first so we can discuss it.
  • Improving this README or adding other documentation to httpsig.
  • Letting me know if you're using httpsig.

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