auth

README

go-iden3-auth

Library for verification of authorization response messages of communication protocol in JWZ format

go get github.com/iden3/go-iden3-auth

General description:

The goal of iden3auth libraries is to handle authentication messages of communication protocol.

Currently, library implementation includes support of next message types

1. https://iden3-communication.io/authorization/1.0/request
2. https://iden3-communication.io/authorization/1.0/response

---

Auth verification procedure:

1. JWZ token verification
2. Zero-knowledge proof verification of request proofs
3. Query request verification for atomic circuits
4. Verification of identity and issuer states for atomic circuits

Zero-knowledge proof verification

Groth16 proof are supported by auth library

Verification keys must be provided using KeyLoader interface

Query verification

Proof for each atomic circuit contains public signals that allow extracting user and issuer identifiers, states, signature, challenges, etc.

Circuit public signals marshallers are defined in the go-circuits library.

Verification of user / issuer identity states

The blockchain verification algorithm is used

1. Gets state from the blockchain (address of id state contract and URL must be provided by the caller of the library):

   1. Empty state is returned - it means that identity state hasn’t been updated or updated state hasn’t been published. We need to compare id and state. If they are different it’s not a genesis state of identity then it’s not valid.
   2. The non-empty state is returned and equals to the state in provided proof which means that the user state is fresh enough and we work with the latest user state.
   3. The non-empty state is returned and it’s not equal to the state that the user has provided. Gets the transition time of the state. The verification party can make a decision if it can accept this state based on that time frame.

2. Only latest states for user are valid. Any existing issuer state for claim issuance is valid.

Verification of GIST

The blockchain verification algorithm is used

1. Get GIST from the blockchain (address of id state contract and URL must be provided by the caller of the library):
   1. A non-empty GIST is returned, equal to the GIST is provided by the user, it means the user is using the latest state.
   2. The non-empty GIST is returned and it’s not equal to the GIST is provided by a user. Gets the transition time of the GIST. The verification party can make a decision if it can accept this state based on that time frame.

How to use:

1. go get https://github.com/iden3/go-iden3-auth

2. Request generation:

   basic auth:

   var request protocol.AuthorizationRequestMessage
   // if you need'message' to sign (e.g. vote)
   request = auth.CreateAuthorizationRequestWithMessage("test flow", "message to sign","verifier id", "callback url")
   // or if you don't need 'message' to sign
   request = auth.CreateAuthorizationRequest("test flow","verifier id", "callback url")
   

   if you want request specific proof (example):

   var mtpProofRequest protocol.ZeroKnowledgeProofRequest
   mtpProofRequest.ID = 1
   mtpProofRequest.CircuitID = string(circuits.AtomicQueryMTPV2CircuitID)
   mtpProofRequest.Query = map[string]interface{}{
      "allowedIssuers": []string{"*"},
      "credentialSubject": map[string]interface{}{
         "countryCode": map[string]interface{}{
            "$nin": []int{840, 120, 340, 509},
         },
      },
      "context": "https://raw.githubusercontent.com/iden3/claim-schema-vocab/main/schemas/json-ld/kyc-v2.json-ld",
      "type":    "KYCCountryOfResidenceCredential",
   }
   request.Body.Scope = append(request.Body.Scope, mtpProofRequest)       
   

3. Token verification

   Init Verifier:

   var verificationKeyloader = &loaders.FSKeyLoader{Dir: keyDIR}
   resolver := state.ETHResolver{
      RPCUrl:          <polygon_node_http>,
      ContractAddress: <state_contract_address>,
   }
   
   resolvers := map[string]pubsignals.StateResolver{
      "polygon:mumbai": resolver,
   }
   verifier,err := auth.NewVerifierWithExplicitError(verificationKeyloader, loaders.DefaultSchemaLoader{IpfsURL: "<IPFS NODE HERE>"}, resolvers)
   // or use NewVerifier and check that verifier instance is not nil. IPFS merklization is not worked without setuping global loader
   // verifier := auth.NewVerifier(verificationKeyloader, loaders.DefaultSchemaLoader{IpfsURL: "ipfs.io"}, resolvers)
   

4. FullVerify:

   authResponse, err := verifier.FullVerify(
      r.Context(), 
      string(tokenBytes),
      authRequest.(protocolAuthorizationRequestMessage), 
      ...VerifyOpt,
   )
   userId = authResponse.from // msg sender
   

   Verify manually if thread id is used a session id to match request with VerifyJWZ / VerifyAuthResponse functions

Notes on prover optimization for x86_64 hardware

See readme in iden3/go-rapidsnark/prover

Contributing

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as below, without any additional terms or conditions.

License

© 2023 0kims Association

This project is licensed under either of

• Apache License, Version 2.0 (LICENSE-APACHE)
• MIT license (LICENSE-MIT)

at your option.

Documentation

Index

• Constants
• Variables
• func CreateAuthorizationRequest(reason, sender, callbackURL string) protocol.AuthorizationRequestMessage
• func CreateAuthorizationRequestWithMessage(reason, message, sender, callbackURL string) protocol.AuthorizationRequestMessage
• func VerifyState(ctx context.Context, id, s *big.Int, opts state.ExtendedVerificationsOptions) error
• type Verifier
  • func NewVerifier(keyLoader loaders.VerificationKeyLoader, ...) *Verifier
  • func NewVerifierWithExplicitError(keyLoader loaders.VerificationKeyLoader, ...) (*Verifier, error)
  • func (v *Verifier) FullVerify(ctx context.Context, token string, ...) (*protocol.AuthorizationResponseMessage, error)
  • func (v *Verifier) SetPackageManager(manager iden3comm.PackageManager)
  • func (v *Verifier) SetPacker(packer iden3comm.Packer) error
  • func (v *Verifier) SetupAuthV2ZKPPacker() error
  • func (v *Verifier) SetupJWSPacker(didResolver packers.DIDResolverHandlerFunc) error
  • func (v *Verifier) VerifyAuthResponse(ctx context.Context, response protocol.AuthorizationResponseMessage, ...) error
  • func (v *Verifier) VerifyJWZ(ctx context.Context, token string, opts ...pubsignals.VerifyOpt) (t *jwz.Token, err error)

Constants

const UniversalResolverURL = "https://dev.uniresolver.io/1.0/identifiers"

UniversalResolverURL is a url for universal resolver

Variables

var UniversalDIDResolver = packers.DIDResolverHandlerFunc(func(did string) (*verifiable.DIDDocument, error) {
	didDoc := &verifiable.DIDDocument{}

	resp, err := http.Get(fmt.Sprintf("%s/%s", UniversalResolverURL, did))

	if err != nil {
		return nil, err
	}

	defer func() {
		err := resp.Body.Close()
		if err != nil {
			log.Fatal(err)
		}
	}()

	body, err := io.ReadAll(resp.Body)
	if err != nil {
		return nil, err
	}

	var didMetadata map[string]interface{}

	err = json.Unmarshal(body, &didMetadata)
	if err != nil {
		return nil, err
	}

	doc, ok := didMetadata["didDocument"]

	if !ok {
		return nil, errors.New("did document not found")
	}

	docBts, err := json.Marshal(doc)

	if err != nil {
		return nil, err
	}

	err = json.Unmarshal(docBts, &didDoc)

	if err != nil {
		return nil, err
	}

	return didDoc, nil
})

UniversalDIDResolver is a resolver for universal resolver

Functions

func CreateAuthorizationRequest

func CreateAuthorizationRequest(reason, sender, callbackURL string) protocol.AuthorizationRequestMessage

CreateAuthorizationRequest creates new authorization request message sender - client identifier reason - describes purpose of request callbackURL - url for authorization response

func CreateAuthorizationRequestWithMessage

func CreateAuthorizationRequestWithMessage(reason, message, sender,
	callbackURL string) protocol.AuthorizationRequestMessage

CreateAuthorizationRequestWithMessage creates new authorization request with message for signing with jwz

func VerifyState

func VerifyState(ctx context.Context, id, s *big.Int, opts state.ExtendedVerificationsOptions) error

VerifyState allows to verify state without binding to verifier instance

Types

type Verifier

type Verifier struct {
	// contains filtered or unexported fields
}

Verifier is a struct for auth instance

func NewVerifier

func NewVerifier(
	keyLoader loaders.VerificationKeyLoader,
	claimSchemaLoader loaders.SchemaLoader,
	resolver map[string]pubsignals.StateResolver,
) *Verifier

NewVerifier returns setup instance of auth library Deprecated: NewVerifier now return nil it can't set up default package manager for verifier, in future major release it will return error

func NewVerifierWithExplicitError

func NewVerifierWithExplicitError(
	keyLoader loaders.VerificationKeyLoader,
	claimSchemaLoader loaders.SchemaLoader,
	resolver map[string]pubsignals.StateResolver,
) (*Verifier, error)

NewVerifierWithExplicitError returns verifier instance with default package manager and explicit error if it couldn't register default packers in future major release it will be renamed to NewVerifier

func (*Verifier) FullVerify

func (v *Verifier) FullVerify(
	ctx context.Context,
	token string,
	request protocol.AuthorizationRequestMessage,
	opts ...pubsignals.VerifyOpt,
) (*protocol.AuthorizationResponseMessage, error)

FullVerify performs verification of jwz token and auth request

func (*Verifier) SetPackageManager

func (v *Verifier) SetPackageManager(manager iden3comm.PackageManager)

SetPackageManager sets the package manager for the VerifierBuilder.

func (*Verifier) SetPacker

func (v *Verifier) SetPacker(packer iden3comm.Packer) error

SetPacker sets the custom packer manager for the VerifierBuilder.

func (*Verifier) SetupAuthV2ZKPPacker

func (v *Verifier) SetupAuthV2ZKPPacker() error

SetupAuthV2ZKPPacker sets the custom packer manager for the VerifierBuilder.

func (*Verifier) SetupJWSPacker

func (v *Verifier) SetupJWSPacker(didResolver packers.DIDResolverHandlerFunc) error

SetupJWSPacker sets the JWS packer for the VerifierBuilder.

func (*Verifier) VerifyAuthResponse

func (v *Verifier) VerifyAuthResponse(
	ctx context.Context,
	response protocol.AuthorizationResponseMessage,
	request protocol.AuthorizationRequestMessage,
	opts ...pubsignals.VerifyOpt,
) error

VerifyAuthResponse performs verification of auth response based on auth request

func (*Verifier) VerifyJWZ

func (v *Verifier) VerifyJWZ(
	ctx context.Context,
	token string,
	opts ...pubsignals.VerifyOpt,
) (t *jwz.Token, err error)

VerifyJWZ performs verification of jwz token