ergo/vendor/github.com/golang-jwt/jwt/v5/README.md

jwt-go

A go (or ‘golang’ for search engine friendliness) implementation of JSON Web Tokens.

Starting with v4.0.0 this project adds Go module support, but maintains backwards compatibility with older v3.x.y tags and upstream github.com/dgrijalva/jwt-go. See the MIGRATION_GUIDE.md for more information. Version v5.0.0 introduces major improvements to the validation of tokens, but is not entirely backwards compatible.

After the original author of the library suggested migrating the maintenance of jwt-go, a dedicated team of open source maintainers decided to clone the existing library into this repository. See dgrijalva/jwt-go#462 for a detailed discussion on this topic.

SECURITY NOTICE: Some older versions of Go have a security issue in the crypto/elliptic. Recommendation is to upgrade to at least 1.15 See issue dgrijalva/jwt-go#216 for more detail.

SECURITY NOTICE: It’s important that you validate the alg presented is what you expect. This library attempts to make it easy to do the right thing by requiring key types match the expected alg, but you should take the extra step to verify it in your usage. See the examples provided.

Supported Go versions

Our support of Go versions is aligned with Go’s version release policy. So we will support a major version of Go until there are two newer major releases. We no longer support building jwt-go with unsupported Go versions, as these contain security vulnerabilities which will not be fixed.

What the heck is a JWT?

JWT.io has a great introduction to JSON Web Tokens.

In short, it’s a signed JSON object that does something useful (for example, authentication). It’s commonly used for Bearer tokens in Oauth 2. A token is made of three parts, separated by .’s. The first two parts are JSON objects, that have been base64url encoded. The last part is the signature, encoded the same way.

The first part is called the header. It contains the necessary information for verifying the last part, the signature. For example, which encryption method was used for signing and what key was used.

The part in the middle is the interesting bit. It’s called the Claims and contains the actual stuff you care about. Refer to RFC 7519 for information about reserved keys and the proper way to add your own.

What’s in the box?

This library supports the parsing and verification as well as the generation and signing of JWTs. Current supported signing algorithms are HMAC SHA, RSA, RSA-PSS, and ECDSA, though hooks are present for adding your own.

Installation Guidelines

1. To install the jwt package, you first need to have Go installed, then you can use the command below to add jwt-go as a dependency in your Go program.

go get -u github.com/golang-jwt/jwt/v5

2. Import it in your code:

import "github.com/golang-jwt/jwt/v5"

Usage

A detailed usage guide, including how to sign and verify tokens can be found on our documentation website.

Examples

See the project documentation for examples of usage:

• Simple example of parsing and validating a token
• Simple example of building and signing a token
• Directory of Examples

Compliance

This library was last reviewed to comply with RFC 7519 dated May 2015 with a few notable differences:

• In order to protect against accidental use of Unsecured JWTs, tokens using alg=none will only be accepted if the constant jwt.UnsafeAllowNoneSignatureType is provided as the key.

Project Status & Versioning

This library is considered production ready. Feedback and feature requests are appreciated. The API should be considered stable. There should be very few backwards-incompatible changes outside of major version updates (and only with good reason).

This project uses Semantic Versioning 2.0.0. Accepted pull requests will land on main. Periodically, versions will be tagged from main. You can find all the releases on the project releases page.

BREAKING CHANGES:* A full list of breaking changes is available in VERSION_HISTORY.md. See MIGRATION_GUIDE.md for more information on updating your code.

Extensions

This library publishes all the necessary components for adding your own signing methods or key functions. Simply implement the SigningMethod interface and register a factory method using RegisterSigningMethod or provide a jwt.Keyfunc.

A common use case would be integrating with different 3rd party signature providers, like key management services from various cloud providers or Hardware Security Modules (HSMs) or to implement additional standards.

Extension	Purpose	Repo
GCP	Integrates with multiple Google Cloud Platform signing tools (AppEngine, IAM API, Cloud KMS)	https://github.com/someone1/gcp-jwt-go
AWS	Integrates with AWS Key Management Service, KMS	https://github.com/matelang/jwt-go-aws-kms
JWKS	Provides support for JWKS (RFC 7517) as a jwt.Keyfunc	https://github.com/MicahParks/keyfunc

Disclaimer: Unless otherwise specified, these integrations are maintained by third parties and should not be considered as a primary offer by any of the mentioned cloud providers

More

Go package documentation can be found on pkg.go.dev. Additional documentation can be found on our project page.

The command line utility included in this project (cmd/jwt) provides a straightforward example of token creation and parsing as well as a useful tool for debugging your own integration. You’ll also find several implementation examples in the documentation.

golang-jwt incorporates a modified version of the JWT logo, which is distributed under the terms of the MIT License.