README

jwt-go

Build Status GoDoc

A go (or 'golang' for search engine friendliness) implementation of JSON Web Tokens

NEW VERSION COMING: There have been a lot of improvements suggested since the version 3.0.0 released in 2016. I'm working now on cutting two different releases: 3.2.0 will contain any non-breaking changes or enhancements. 4.0.0 will follow shortly which will include breaking changes. See the 4.0.0 milestone to get an idea of what's coming. If you have other ideas, or would like to participate in 4.0.0, now's the time. If you depend on this library and don't want to be interrupted, I recommend you use your dependency mangement tool to pin to version 3.

SECURITY NOTICE: Some older versions of Go have a security issue in the cryotp/elliptic. Recommendation is to upgrade to at least 1.8.3. See issue #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.

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 the RFC 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.

Examples

See the project documentation for examples of usage:

Extensions

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

Here's an example of an extension that integrates with the Google App Engine signing tools: https://github.com/someone1/gcp-jwt-go

Compliance

This library was last reviewed to comply with RTF 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 master. Periodically, versions will be tagged from master. You can find all the releases on the project releases page.

While we try to make it obvious when we make breaking changes, there isn't a great mechanism for pushing announcements out to users. You may want to use this alternative package include: gopkg.in/dgrijalva/jwt-go.v3. It will do the right thing WRT semantic versioning.

BREAKING CHANGES:*

  • Version 3.0.0 includes a lot of changes from the 2.x line, including a few that break the API. We've tried to break as few things as possible, so there should just be a few type signature changes. A full list of breaking changes is available in VERSION_HISTORY.md. See MIGRATION_GUIDE.md for more information on updating your code.

Usage Tips

Signing vs Encryption

A token is simply a JSON object that is signed by its author. this tells you exactly two things about the data:

  • The author of the token was in the possession of the signing secret
  • The data has not been modified since it was signed

It's important to know that JWT does not provide encryption, which means anyone who has access to the token can read its contents. If you need to protect (encrypt) the data, there is a companion spec, JWE, that provides this functionality. JWE is currently outside the scope of this library.

Choosing a Signing Method

There are several signing methods available, and you should probably take the time to learn about the various options before choosing one. The principal design decision is most likely going to be symmetric vs asymmetric.

Symmetric signing methods, such as HSA, use only a single secret. This is probably the simplest signing method to use since any []byte can be used as a valid secret. They are also slightly computationally faster to use, though this rarely is enough to matter. Symmetric signing methods work the best when both producers and consumers of tokens are trusted, or even the same system. Since the same secret is used to both sign and validate tokens, you can't easily distribute the key for validation.

Asymmetric signing methods, such as RSA, use different keys for signing and verifying tokens. This makes it possible to produce tokens with a private key, and allow any consumer to access the public key for verification.

Signing Methods and Key Types

Each signing method expects a different object type for its signing keys. See the package documentation for details. Here are the most common ones:

  • The HMAC signing method (HS256,HS384,HS512) expect []byte values for signing and validation
  • The RSA signing method (RS256,RS384,RS512) expect *rsa.PrivateKey for signing and *rsa.PublicKey for validation
  • The ECDSA signing method (ES256,ES384,ES512) expect *ecdsa.PrivateKey for signing and *ecdsa.PublicKey for validation
JWT and OAuth

It's worth mentioning that OAuth and JWT are not the same thing. A JWT token is simply a signed JSON object. It can be used anywhere such a thing is useful. There is some confusion, though, as JWT is the most common type of bearer token used in OAuth2 authentication.

Without going too far down the rabbit hole, here's a description of the interaction of these technologies:

  • OAuth is a protocol for allowing an identity provider to be separate from the service a user is logging in to. For example, whenever you use Facebook to log into a different service (Yelp, Spotify, etc), you are using OAuth.
  • OAuth defines several options for passing around authentication data. One popular method is called a "bearer token". A bearer token is simply a string that should only be held by an authenticated user. Thus, simply presenting this token proves your identity. You can probably derive from here why a JWT might make a good bearer token.
  • Because bearer tokens are used for authentication, it's important they're kept secret. This is why transactions that use bearer tokens typically happen over SSL.

More

Documentation can be found on godoc.org.

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.

Expand ▾ Collapse ▴

Documentation

Overview

    Package jwt is a Go implementation of JSON Web Tokens: http://self-issued.info/docs/draft-jones-json-web-token.html

    See README.md for more info.

    Example (GetTokenViaHTTP)
    Output:
    
    test
    
    Example (UseTokenViaHTTP)
    Output:
    
    Welcome, foo
    

    Index

    Examples

    Constants

    View Source
    const (
    	ValidationErrorMalformed        uint32 = 1 << iota // Token is malformed
    	ValidationErrorUnverifiable                        // Token could not be verified because of signing problems
    	ValidationErrorSignatureInvalid                    // Signature validation failed
    
    	// Standard Claim validation errors
    	ValidationErrorAudience      // AUD validation failed
    	ValidationErrorExpired       // EXP validation failed
    	ValidationErrorIssuedAt      // IAT validation failed
    	ValidationErrorIssuer        // ISS validation failed
    	ValidationErrorNotValidYet   // NBF validation failed
    	ValidationErrorId            // JTI validation failed
    	ValidationErrorClaimsInvalid // Generic claims validation error
    )

      The errors that might occur when parsing and validating a token

      View Source
      const UnsafeAllowNoneSignatureType unsafeNoneMagicConstant = "none signing method allowed"

      Variables

      View Source
      var (
      	ErrNotECPublicKey  = errors.New("Key is not a valid ECDSA public key")
      	ErrNotECPrivateKey = errors.New("Key is not a valid ECDSA private key")
      )
      View Source
      var (
      	ErrInvalidKey      = errors.New("key is invalid")
      	ErrInvalidKeyType  = errors.New("key is of invalid type")
      	ErrHashUnavailable = errors.New("the requested hash function is unavailable")
      )

        Error constants

        View Source
        var (
        	ErrKeyMustBePEMEncoded = errors.New("Invalid Key: Key must be PEM encoded PKCS1 or PKCS8 private key")
        	ErrNotRSAPrivateKey    = errors.New("Key is not a valid RSA private key")
        	ErrNotRSAPublicKey     = errors.New("Key is not a valid RSA public key")
        )
        View Source
        var (
        	// Sadly this is missing from crypto/ecdsa compared to crypto/rsa
        	ErrECDSAVerification = errors.New("crypto/ecdsa: verification error")
        )
        View Source
        var NoneSignatureTypeDisallowedError error
        View Source
        var SigningMethodNone *signingMethodNone

          Implements the none signing method. This is required by the spec but you probably should never use it.

          View Source
          var TimeFunc = time.Now

            TimeFunc provides the current time when parsing token to validate "exp" claim (expiration time). You can override it to use another time value. This is useful for testing or if your server uses a different time zone than your tokens.

            Functions

            func DecodeSegment

            func DecodeSegment(seg string) ([]byte, error)

              Decode JWT specific base64url encoding with padding stripped

              func EncodeSegment

              func EncodeSegment(seg []byte) string

                Encode JWT specific base64url encoding with padding stripped

                func ParseECPrivateKeyFromPEM

                func ParseECPrivateKeyFromPEM(key []byte) (*ecdsa.PrivateKey, error)

                  Parse PEM encoded Elliptic Curve Private Key Structure

                  func ParseECPublicKeyFromPEM

                  func ParseECPublicKeyFromPEM(key []byte) (*ecdsa.PublicKey, error)

                    Parse PEM encoded PKCS1 or PKCS8 public key

                    func ParseRSAPrivateKeyFromPEM

                    func ParseRSAPrivateKeyFromPEM(key []byte) (*rsa.PrivateKey, error)

                      Parse PEM encoded PKCS1 or PKCS8 private key

                      func ParseRSAPrivateKeyFromPEMWithPassword

                      func ParseRSAPrivateKeyFromPEMWithPassword(key []byte, password string) (*rsa.PrivateKey, error)

                        Parse PEM encoded PKCS1 or PKCS8 private key protected with password

                        func ParseRSAPublicKeyFromPEM

                        func ParseRSAPublicKeyFromPEM(key []byte) (*rsa.PublicKey, error)

                          Parse PEM encoded PKCS1 or PKCS8 public key

                          func RegisterSigningMethod

                          func RegisterSigningMethod(alg string, f func() SigningMethod)

                            Register the "alg" name and a factory function for signing method. This is typically done during init() in the method's implementation

                            Types

                            type Claims

                            type Claims interface {
                            	Valid() error
                            }

                              For a type to be a Claims object, it must just have a Valid method that determines if the token is invalid for any supported reason

                              type Keyfunc

                              type Keyfunc func(*Token) (interface{}, error)

                                Parse methods use this callback function to supply the key for verification. The function receives the parsed, but unverified Token. This allows you to use properties in the Header of the token (such as `kid`) to identify which key to use.

                                type MapClaims

                                type MapClaims map[string]interface{}

                                  Claims type that uses the map[string]interface{} for JSON decoding This is the default claims type if you don't supply one

                                  func (MapClaims) Valid

                                  func (m MapClaims) Valid() error

                                    Validates time based claims "exp, iat, nbf". There is no accounting for clock skew. As well, if any of the above claims are not in the token, it will still be considered a valid claim.

                                    func (MapClaims) VerifyAudience

                                    func (m MapClaims) VerifyAudience(cmp string, req bool) bool

                                      Compares the aud claim against cmp. If required is false, this method will return true if the value matches or is unset

                                      func (MapClaims) VerifyExpiresAt

                                      func (m MapClaims) VerifyExpiresAt(cmp int64, req bool) bool

                                        Compares the exp claim against cmp. If required is false, this method will return true if the value matches or is unset

                                        func (MapClaims) VerifyIssuedAt

                                        func (m MapClaims) VerifyIssuedAt(cmp int64, req bool) bool

                                          Compares the iat claim against cmp. If required is false, this method will return true if the value matches or is unset

                                          func (MapClaims) VerifyIssuer

                                          func (m MapClaims) VerifyIssuer(cmp string, req bool) bool

                                            Compares the iss claim against cmp. If required is false, this method will return true if the value matches or is unset

                                            func (MapClaims) VerifyNotBefore

                                            func (m MapClaims) VerifyNotBefore(cmp int64, req bool) bool

                                              Compares the nbf claim against cmp. If required is false, this method will return true if the value matches or is unset

                                              type Parser

                                              type Parser struct {
                                              	ValidMethods         []string // If populated, only these methods will be considered valid
                                              	UseJSONNumber        bool     // Use JSON Number format in JSON decoder
                                              	SkipClaimsValidation bool     // Skip claims validation during token parsing
                                              }

                                              func (*Parser) Parse

                                              func (p *Parser) Parse(tokenString string, keyFunc Keyfunc) (*Token, error)

                                                Parse, validate, and return a token. keyFunc will receive the parsed token and should return the key for validating. If everything is kosher, err will be nil

                                                func (*Parser) ParseUnverified

                                                func (p *Parser) ParseUnverified(tokenString string, claims Claims) (token *Token, parts []string, err error)

                                                  WARNING: Don't use this method unless you know what you're doing

                                                  This method parses the token but doesn't validate the signature. It's only ever useful in cases where you know the signature is valid (because it has been checked previously in the stack) and you want to extract values from it.

                                                  func (*Parser) ParseWithClaims

                                                  func (p *Parser) ParseWithClaims(tokenString string, claims Claims, keyFunc Keyfunc) (*Token, error)

                                                  type SigningMethod

                                                  type SigningMethod interface {
                                                  	Verify(signingString, signature string, key interface{}) error // Returns nil if signature is valid
                                                  	Sign(signingString string, key interface{}) (string, error)    // Returns encoded signature or error
                                                  	Alg() string                                                   // returns the alg identifier for this method (example: 'HS256')
                                                  }

                                                    Implement SigningMethod to add new methods for signing or verifying tokens.

                                                    func GetSigningMethod

                                                    func GetSigningMethod(alg string) (method SigningMethod)

                                                      Get a signing method from an "alg" string

                                                      type SigningMethodECDSA

                                                      type SigningMethodECDSA struct {
                                                      	Name      string
                                                      	Hash      crypto.Hash
                                                      	KeySize   int
                                                      	CurveBits int
                                                      }

                                                        Implements the ECDSA family of signing methods signing methods Expects *ecdsa.PrivateKey for signing and *ecdsa.PublicKey for verification

                                                        var (
                                                        	SigningMethodES256 *SigningMethodECDSA
                                                        	SigningMethodES384 *SigningMethodECDSA
                                                        	SigningMethodES512 *SigningMethodECDSA
                                                        )

                                                          Specific instances for EC256 and company

                                                          func (*SigningMethodECDSA) Alg

                                                          func (m *SigningMethodECDSA) Alg() string

                                                          func (*SigningMethodECDSA) Sign

                                                          func (m *SigningMethodECDSA) Sign(signingString string, key interface{}) (string, error)

                                                            Implements the Sign method from SigningMethod For this signing method, key must be an ecdsa.PrivateKey struct

                                                            func (*SigningMethodECDSA) Verify

                                                            func (m *SigningMethodECDSA) Verify(signingString, signature string, key interface{}) error

                                                              Implements the Verify method from SigningMethod For this verify method, key must be an ecdsa.PublicKey struct

                                                              type SigningMethodHMAC

                                                              type SigningMethodHMAC struct {
                                                              	Name string
                                                              	Hash crypto.Hash
                                                              }

                                                                Implements the HMAC-SHA family of signing methods signing methods Expects key type of []byte for both signing and validation

                                                                var (
                                                                	SigningMethodHS256  *SigningMethodHMAC
                                                                	SigningMethodHS384  *SigningMethodHMAC
                                                                	SigningMethodHS512  *SigningMethodHMAC
                                                                	ErrSignatureInvalid = errors.New("signature is invalid")
                                                                )

                                                                  Specific instances for HS256 and company

                                                                  func (*SigningMethodHMAC) Alg

                                                                  func (m *SigningMethodHMAC) Alg() string

                                                                  func (*SigningMethodHMAC) Sign

                                                                  func (m *SigningMethodHMAC) Sign(signingString string, key interface{}) (string, error)

                                                                    Implements the Sign method from SigningMethod for this signing method. Key must be []byte

                                                                    func (*SigningMethodHMAC) Verify

                                                                    func (m *SigningMethodHMAC) Verify(signingString, signature string, key interface{}) error

                                                                      Verify the signature of HSXXX tokens. Returns nil if the signature is valid.

                                                                      type SigningMethodRSA

                                                                      type SigningMethodRSA struct {
                                                                      	Name string
                                                                      	Hash crypto.Hash
                                                                      }

                                                                        Implements the RSA family of signing methods signing methods Expects *rsa.PrivateKey for signing and *rsa.PublicKey for validation

                                                                        var (
                                                                        	SigningMethodRS256 *SigningMethodRSA
                                                                        	SigningMethodRS384 *SigningMethodRSA
                                                                        	SigningMethodRS512 *SigningMethodRSA
                                                                        )

                                                                          Specific instances for RS256 and company

                                                                          func (*SigningMethodRSA) Alg

                                                                          func (m *SigningMethodRSA) Alg() string

                                                                          func (*SigningMethodRSA) Sign

                                                                          func (m *SigningMethodRSA) Sign(signingString string, key interface{}) (string, error)

                                                                            Implements the Sign method from SigningMethod For this signing method, must be an *rsa.PrivateKey structure.

                                                                            func (*SigningMethodRSA) Verify

                                                                            func (m *SigningMethodRSA) Verify(signingString, signature string, key interface{}) error

                                                                              Implements the Verify method from SigningMethod For this signing method, must be an *rsa.PublicKey structure.

                                                                              type SigningMethodRSAPSS

                                                                              type SigningMethodRSAPSS struct {
                                                                              	*SigningMethodRSA
                                                                              	Options *rsa.PSSOptions
                                                                              }

                                                                                Implements the RSAPSS family of signing methods signing methods

                                                                                var (
                                                                                	SigningMethodPS256 *SigningMethodRSAPSS
                                                                                	SigningMethodPS384 *SigningMethodRSAPSS
                                                                                	SigningMethodPS512 *SigningMethodRSAPSS
                                                                                )

                                                                                  Specific instances for RS/PS and company

                                                                                  func (*SigningMethodRSAPSS) Sign

                                                                                  func (m *SigningMethodRSAPSS) Sign(signingString string, key interface{}) (string, error)

                                                                                    Implements the Sign method from SigningMethod For this signing method, key must be an rsa.PrivateKey struct

                                                                                    func (*SigningMethodRSAPSS) Verify

                                                                                    func (m *SigningMethodRSAPSS) Verify(signingString, signature string, key interface{}) error

                                                                                      Implements the Verify method from SigningMethod For this verify method, key must be an rsa.PublicKey struct

                                                                                      type StandardClaims

                                                                                      type StandardClaims struct {
                                                                                      	Audience  string `json:"aud,omitempty"`
                                                                                      	ExpiresAt int64  `json:"exp,omitempty"`
                                                                                      	Id        string `json:"jti,omitempty"`
                                                                                      	IssuedAt  int64  `json:"iat,omitempty"`
                                                                                      	Issuer    string `json:"iss,omitempty"`
                                                                                      	NotBefore int64  `json:"nbf,omitempty"`
                                                                                      	Subject   string `json:"sub,omitempty"`
                                                                                      }

                                                                                        Structured version of Claims Section, as referenced at https://tools.ietf.org/html/rfc7519#section-4.1 See examples for how to use this with your own claim types

                                                                                        func (StandardClaims) Valid

                                                                                        func (c StandardClaims) Valid() error

                                                                                          Validates time based claims "exp, iat, nbf". There is no accounting for clock skew. As well, if any of the above claims are not in the token, it will still be considered a valid claim.

                                                                                          func (*StandardClaims) VerifyAudience

                                                                                          func (c *StandardClaims) VerifyAudience(cmp string, req bool) bool

                                                                                            Compares the aud claim against cmp. If required is false, this method will return true if the value matches or is unset

                                                                                            func (*StandardClaims) VerifyExpiresAt

                                                                                            func (c *StandardClaims) VerifyExpiresAt(cmp int64, req bool) bool

                                                                                              Compares the exp claim against cmp. If required is false, this method will return true if the value matches or is unset

                                                                                              func (*StandardClaims) VerifyIssuedAt

                                                                                              func (c *StandardClaims) VerifyIssuedAt(cmp int64, req bool) bool

                                                                                                Compares the iat claim against cmp. If required is false, this method will return true if the value matches or is unset

                                                                                                func (*StandardClaims) VerifyIssuer

                                                                                                func (c *StandardClaims) VerifyIssuer(cmp string, req bool) bool

                                                                                                  Compares the iss claim against cmp. If required is false, this method will return true if the value matches or is unset

                                                                                                  func (*StandardClaims) VerifyNotBefore

                                                                                                  func (c *StandardClaims) VerifyNotBefore(cmp int64, req bool) bool

                                                                                                    Compares the nbf claim against cmp. If required is false, this method will return true if the value matches or is unset

                                                                                                    type Token

                                                                                                    type Token struct {
                                                                                                    	Raw       string                 // The raw token.  Populated when you Parse a token
                                                                                                    	Method    SigningMethod          // The signing method used or to be used
                                                                                                    	Header    map[string]interface{} // The first segment of the token
                                                                                                    	Claims    Claims                 // The second segment of the token
                                                                                                    	Signature string                 // The third segment of the token.  Populated when you Parse a token
                                                                                                    	Valid     bool                   // Is the token valid?  Populated when you Parse/Verify a token
                                                                                                    }

                                                                                                      A JWT Token. Different fields will be used depending on whether you're creating or parsing/verifying a token.

                                                                                                      func New

                                                                                                      func New(method SigningMethod) *Token

                                                                                                        Create a new Token. Takes a signing method

                                                                                                        Example (Hmac)

                                                                                                          Example creating, signing, and encoding a JWT token using the HMAC signing method

                                                                                                          Output:
                                                                                                          
                                                                                                          eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJmb28iOiJiYXIiLCJuYmYiOjE0NDQ0Nzg0MDB9.u1riaD1rW97opCoAuRCTy4w58Br-Zk-bh7vLiRIsrpU <nil>
                                                                                                          

                                                                                                          func NewWithClaims

                                                                                                          func NewWithClaims(method SigningMethod, claims Claims) *Token
                                                                                                          Example (CustomClaimsType)

                                                                                                            Example creating a token using a custom claims type. The StandardClaim is embedded in the custom type to allow for easy encoding, parsing and validation of standard claims.

                                                                                                            Output:
                                                                                                            
                                                                                                            eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJmb28iOiJiYXIiLCJleHAiOjE1MDAwLCJpc3MiOiJ0ZXN0In0.HE7fK0xOQwFEr4WDgRWj4teRPZ6i3GLwD5YCm6Pwu_c <nil>
                                                                                                            
                                                                                                            Example (StandardClaims)

                                                                                                              Example (atypical) using the StandardClaims type by itself to parse a token. The StandardClaims type is designed to be embedded into your custom types to provide standard validation features. You can use it alone, but there's no way to retrieve other fields after parsing. See the CustomClaimsType example for intended usage.

                                                                                                              Output:
                                                                                                              
                                                                                                              eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJleHAiOjE1MDAwLCJpc3MiOiJ0ZXN0In0.QsODzZu3lUZMVdhbO76u3Jv02iYCvEHcYVUI1kOWEU0 <nil>
                                                                                                              

                                                                                                              func Parse

                                                                                                              func Parse(tokenString string, keyFunc Keyfunc) (*Token, error)

                                                                                                                Parse, validate, and return a token. keyFunc will receive the parsed token and should return the key for validating. If everything is kosher, err will be nil

                                                                                                                Example (ErrorChecking)

                                                                                                                  An example of parsing the error types using bitfield checks

                                                                                                                  Output:
                                                                                                                  
                                                                                                                  Timing is everything
                                                                                                                  
                                                                                                                  Example (Hmac)

                                                                                                                    Example parsing and validating a token using the HMAC signing method

                                                                                                                    Output:
                                                                                                                    
                                                                                                                    bar 1.4444784e+09
                                                                                                                    

                                                                                                                    func ParseWithClaims

                                                                                                                    func ParseWithClaims(tokenString string, claims Claims, keyFunc Keyfunc) (*Token, error)
                                                                                                                    Example (CustomClaimsType)

                                                                                                                      Example creating a token using a custom claims type. The StandardClaim is embedded in the custom type to allow for easy encoding, parsing and validation of standard claims.

                                                                                                                      Output:
                                                                                                                      
                                                                                                                      bar 15000
                                                                                                                      

                                                                                                                      func (*Token) SignedString

                                                                                                                      func (t *Token) SignedString(key interface{}) (string, error)

                                                                                                                        Get the complete, signed token

                                                                                                                        func (*Token) SigningString

                                                                                                                        func (t *Token) SigningString() (string, error)

                                                                                                                          Generate the signing string. This is the most expensive part of the whole deal. Unless you need this for something special, just go straight for the SignedString.

                                                                                                                          type ValidationError

                                                                                                                          type ValidationError struct {
                                                                                                                          	Inner  error  // stores the error returned by external dependencies, i.e.: KeyFunc
                                                                                                                          	Errors uint32 // bitfield.  see ValidationError... constants
                                                                                                                          	// contains filtered or unexported fields
                                                                                                                          }

                                                                                                                            The error from Parse if token is not valid

                                                                                                                            func NewValidationError

                                                                                                                            func NewValidationError(errorText string, errorFlags uint32) *ValidationError

                                                                                                                              Helper for constructing a ValidationError with a string error message

                                                                                                                              func (ValidationError) Error

                                                                                                                              func (e ValidationError) Error() string

                                                                                                                                Validation error is an error type

                                                                                                                                Directories

                                                                                                                                Path Synopsis
                                                                                                                                cmd
                                                                                                                                jwt
                                                                                                                                A useful example app.
                                                                                                                                A useful example app.
                                                                                                                                Utility package for extracting JWT tokens from HTTP requests.
                                                                                                                                Utility package for extracting JWT tokens from HTTP requests.