Merge branch 'v1' into v1-policy-subset-selection

delegation/schema_test.go

@@ -1,82 +0,0 @@
-package delegation_test
-
-import (
-	_ "embed"
-	"fmt"
-	"testing"
-
-	"github.com/ipld/go-ipld-prime"
-	"github.com/stretchr/testify/require"
-	"gotest.tools/v3/golden"
-
-	"github.com/ucan-wg/go-ucan/delegation"
-)
-
-//go:embed delegation.ipldsch
-var schemaBytes []byte
-
-func TestSchemaRoundTrip(t *testing.T) {
-	// 	const delegationJson = `
-	// {
-	//   "aud":"did:key:def456",
-	//   "cmd":"/foo/bar",
-	//   "exp":123456,
-	//   "iss":"did:key:abc123",
-	//   "meta":{
-	//     "bar":"baaar",
-	//     "foo":"fooo"
-	//   },
-	//   "nbf":123456,
-	//   "nonce":{
-	//     "/":{
-	//       "bytes":"c3VwZXItcmFuZG9t"
-	//     }
-	//   },
-	//   "pol":[
-	//     ["==", ".status", "draft"],
-	//     ["all", ".reviewer", [
-	// 		["like", ".email", "*@example.com"]]
-	// 	],
-	//     ["any", ".tags", [
-	// 		["or", [
-	// 			["==", ".", "news"],
-	// 			["==", ".", "press"]]
-	//       ]]
-	// 	]
-	//   ],
-	//   "sub":""
-	// }
-	// `
-
-	delegationJson := golden.Get(t, "new.dagjson")
-	privKey := privKey(t, issuerPrivKeyCfg)
-
-	// format:    dagJson   -->   PayloadModel   -->   dagCbor   -->   PayloadModel   -->   dagJson
-	// function:      DecodeDagJson()      EncodeDagCbor()   DecodeDagCbor()     EncodeDagJson()
-
-	p1, err := delegation.FromDagJson([]byte(delegationJson))
-	require.NoError(t, err)
-
-	cborBytes, err := p1.ToDagCbor(privKey)
-	require.NoError(t, err)
-	fmt.Println("cborBytes length", len(cborBytes))
-	fmt.Println("cbor", string(cborBytes))
-
-	p2, err := delegation.FromDagCbor(cborBytes)
-	require.NoError(t, err)
-	fmt.Println("read Cbor", p2)
-
-	readJson, err := p2.ToDagJson(privKey)
-	require.NoError(t, err)
-	fmt.Println("readJson length", len(readJson))
-	fmt.Println("json: ", string(readJson))
-
-	require.JSONEq(t, string(delegationJson), string(readJson))
-}
-
-func BenchmarkSchemaLoad(b *testing.B) {
-	b.ReportAllocs()
-	for i := 0; i < b.N; i++ {
-		_, _ = ipld.LoadSchemaBytes(schemaBytes)
-	}
-}

go.mod

@@ -10,6 +10,7 @@ require (
 	github.com/libp2p/go-libp2p v0.36.3
 	github.com/multiformats/go-multibase v0.2.0
 	github.com/multiformats/go-multicodec v0.9.0
+	github.com/multiformats/go-multihash v0.2.3
 	github.com/multiformats/go-varint v0.0.7
 	github.com/stretchr/testify v1.9.0
 	gotest.tools/v3 v3.5.1
@@ -24,7 +25,6 @@ require (
 	github.com/mr-tron/base58 v1.2.0 // indirect
 	github.com/multiformats/go-base32 v0.1.0 // indirect
 	github.com/multiformats/go-base36 v0.2.0 // indirect
-	github.com/multiformats/go-multihash v0.2.3 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
 	github.com/polydawn/refmt v0.89.0 // indirect
 	github.com/spaolacci/murmur3 v1.1.0 // indirect

pkg/command/command_test.go

@@ -5,7 +5,7 @@ import (
 
 	"github.com/stretchr/testify/require"
 
-	"github.com/ucan-wg/go-ucan/capability/command"
+	"github.com/ucan-wg/go-ucan/pkg/command"
 )
 
 func TestTop(t *testing.T) {

pkg/meta/meta.go

@@ -2,12 +2,16 @@ package meta
 
 import (
 	"errors"
+	"fmt"
+	"reflect"
 
 	"github.com/ipld/go-ipld-prime"
 	"github.com/ipld/go-ipld-prime/datamodel"
 	"github.com/ipld/go-ipld-prime/node/basicnode"
 )
 
+var ErrUnsupported = errors.New("failure adding unsupported type to meta")
+
 var ErrNotFound = errors.New("key-value not found in meta")
 
 // Meta is a container for meta key-value pairs in a UCAN token.
@@ -113,8 +117,20 @@ func (m *Meta) Add(key string, val any) error {
 	case datamodel.Node:
 		m.Values[key] = val
 	default:
-		panic("invalid value type")
+		return fmt.Errorf("%w: %s", ErrUnsupported, fqtn(val))
 	}
 	m.Keys = append(m.Keys, key)
 	return nil
 }
+
+func fqtn(val any) string {
+	var name string
+
+	t := reflect.TypeOf(val)
+	for t.Kind() == reflect.Pointer {
+		name += "*"
+		t = t.Elem()
+	}
+
+	return name + t.PkgPath() + "." + t.Name()
+}

pkg/meta/meta_test.go

@@ -0,0 +1,23 @@
+package meta_test
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+	"github.com/ucan-wg/go-ucan/pkg/meta"
+	"gotest.tools/v3/assert"
+)
+
+func TestMeta_Add(t *testing.T) {
+	t.Parallel()
+
+	type Unsupported struct{}
+
+	t.Run("error if not primative or Node", func(t *testing.T) {
+		t.Parallel()
+
+		err := (&meta.Meta{}).Add("invalid", &Unsupported{})
+		require.ErrorIs(t, err, meta.ErrUnsupported)
+		assert.ErrorContains(t, err, "*github.com/ucan-wg/go-ucan/pkg/meta_test.Unsupported")
+	})
+}

pkg/policy/ipld.go

@@ -9,7 +9,7 @@ import (
 	"github.com/ipld/go-ipld-prime/must"
 	"github.com/ipld/go-ipld-prime/node/basicnode"
 
-	"github.com/ucan-wg/go-ucan/capability/policy/selector"
+	"github.com/ucan-wg/go-ucan/pkg/policy/selector"
 )
 
 func FromIPLD(node datamodel.Node) (Policy, error) {

pkg/policy/match.go

@@ -8,7 +8,7 @@ import (
 	"github.com/ipld/go-ipld-prime/datamodel"
 	"github.com/ipld/go-ipld-prime/must"
 
-	"github.com/ucan-wg/go-ucan/capability/policy/selector"
+	"github.com/ucan-wg/go-ucan/pkg/policy/selector"
 )
 
 func (p Policy) Filter(sel selector.Selector) Policy {

pkg/policy/match_test.go

@@ -14,8 +14,8 @@ import (
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 
-	"github.com/ucan-wg/go-ucan/capability/policy/literal"
-	"github.com/ucan-wg/go-ucan/capability/policy/selector"
+	"github.com/ucan-wg/go-ucan/pkg/policy/literal"
+	"github.com/ucan-wg/go-ucan/pkg/policy/selector"
 )
 
 func TestMatch(t *testing.T) {

pkg/policy/policy.go

@@ -5,7 +5,7 @@ package policy
 import (
 	"github.com/ipld/go-ipld-prime"
 
-	"github.com/ucan-wg/go-ucan/capability/policy/selector"
+	"github.com/ucan-wg/go-ucan/pkg/policy/selector"
 )
 
 const (

pkg/policy/selector/supported_test.go

@@ -12,7 +12,7 @@ import (
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 
-	"github.com/ucan-wg/go-ucan/capability/policy/selector"
+	"github.com/ucan-wg/go-ucan/pkg/policy/selector"
 )
 
 // TestSupported Forms runs tests against the Selector according to the

tokens/delegation/delegation.go

@@ -1,19 +1,30 @@
+// Package delegation implements the UCAN [delegation] specification with
+// an immutable Token type as well as methods to convert the Token to and
+// from the [envelope]-enclosed, signed and DAG-CBOR-encoded form that
+// should most commonly be used for transport and storage.
+//
+// [delegation]: https://github.com/ucan-wg/delegation/tree/v1_ipld
+// [envelope]: https://github.com/ucan-wg/spec#envelope
 package delegation
 
+// TODO: change the "delegation" link above when the specification is merged
+
 import (
 	"crypto/rand"
 	"errors"
 	"fmt"
 	"time"
 
+	"github.com/ipfs/go-cid"
 	"github.com/libp2p/go-libp2p/core/crypto"
 
-	"github.com/ucan-wg/go-ucan/capability/command"
-	"github.com/ucan-wg/go-ucan/capability/policy"
 	"github.com/ucan-wg/go-ucan/did"
+	"github.com/ucan-wg/go-ucan/pkg/command"
 	"github.com/ucan-wg/go-ucan/pkg/meta"
+	"github.com/ucan-wg/go-ucan/pkg/policy"
 )
 
+// Token is an immutable type that holds the fields of a UCAN delegation.
 type Token struct {
 	// Issuer DID (sender)
 	issuer did.DID
@@ -33,6 +44,8 @@ type Token struct {
 	notBefore *time.Time
 	// The timestamp at which the Invocation becomes invalid
 	expiration *time.Time
+	// The CID of the Token when enclosed in an Envelope and encoded to DAG-CBOR
+	cid cid.Cid
 }
 
 // New creates a validated Token from the provided parameters and options.
@@ -50,6 +63,7 @@ func New(privKey crypto.PrivKey, aud did.DID, cmd command.Command, pol policy.Po
 		policy:   pol,
 		meta:     meta.NewMeta(),
 		nonce:    nil,
+		cid:      cid.Undef,
 	}
 
 	for _, opt := range opts {
@@ -132,6 +146,13 @@ func (t *Token) Expiration() *time.Time {
 	return t.expiration
 }
 
+// CID returns the content identifier of the Token model when enclosed
+// in an Envelope and encoded to DAG-CBOR.
+// Returns cid.Undef if the token has not been serialized or deserialized yet.
+func (t *Token) CID() cid.Cid {
+	return t.cid
+}
+
 func (t *Token) validate() error {
 	var errs error
 
@@ -151,70 +172,6 @@ func (t *Token) validate() error {
 	return errs
 }
 
-type Option func(*Token) error
-
-// WithExpiration set's the Token's optional "expiration" field to the
-// value of the provided time.Time.
-func WithExpiration(exp time.Time) Option {
-	return func(t *Token) error {
-		if exp.Before(time.Now()) {
-			return fmt.Errorf("a Token's expiration should be set to a time in the future: %s", exp.String())
-		}
-
-		t.expiration = &exp
-
-		return nil
-	}
-}
-
-// WithMeta adds a key/value pair in the "meta" field.
-// WithMeta can be used multiple times in the same call.
-// Accepted types for the value are: bool, string, int, int32, int64, []byte,
-// and ipld.Node.
-func WithMeta(key string, val any) Option {
-	return func(t *Token) error {
-		return t.meta.Add(key, val)
-	}
-}
-
-// WithNotBefore set's the Token's optional "notBefore" field to the value
-// of the provided time.Time.
-func WithNotBefore(nbf time.Time) Option {
-	return func(t *Token) error {
-		if nbf.Before(time.Now()) {
-			return fmt.Errorf("a Token's \"not before\" field should be set to a time in the future: %s", nbf.String())
-		}
-
-		t.notBefore = &nbf
-
-		return nil
-	}
-}
-
-// WithSubject sets the Tokens's optional "subject" field to the value of
-// provided did.DID.
-//
-// This Option should only be used with the New constructor - since
-// Subject is a required parameter when creating a Token via the  Root
-// constructor, any value provided via this Option will be silently
-// overwritten.
-func WithSubject(sub did.DID) Option {
-	return func(t *Token) error {
-		t.subject = sub
-
-		return nil
-	}
-}
-
-// WithNonce sets the Token's nonce with the given value.
-// If this option is not used, a random 12-byte nonce is generated for this required field.
-func WithNonce(nonce []byte) Option {
-	return func(t *Token) error {
-		t.nonce = nonce
-		return nil
-	}
-}
-
 // tokenFromModel build a decoded view of the raw IPLD data.
 // This function also serves as validation.
 func tokenFromModel(m tokenPayloadModel) (*Token, error) {
@@ -277,6 +234,7 @@ func tokenFromModel(m tokenPayloadModel) (*Token, error) {
 }
 
 // generateNonce creates a 12-byte random nonce.
+// TODO: some crypto scheme require more, is that our case?
 func generateNonce() ([]byte, error) {
 	res := make([]byte, 12)
 	_, err := rand.Read(res)

tokens/delegation/delegation_test.go

@@ -1,7 +1,6 @@
 package delegation_test
 
 import (
-	"crypto/rand"
 	"testing"
 	"time"
 
@@ -9,10 +8,10 @@ import (
 	"github.com/stretchr/testify/require"
 	"gotest.tools/v3/golden"
 
-	"github.com/ucan-wg/go-ucan/capability/command"
-	"github.com/ucan-wg/go-ucan/capability/policy"
-	"github.com/ucan-wg/go-ucan/delegation"
 	"github.com/ucan-wg/go-ucan/did"
+	"github.com/ucan-wg/go-ucan/pkg/command"
+	"github.com/ucan-wg/go-ucan/pkg/policy"
+	"github.com/ucan-wg/go-ucan/tokens/delegation"
 )
 
 const (
@@ -64,6 +63,9 @@ const (
 	]
 ]
 `
+
+	newCID  = "zdpuAn9JgGPvnt2WCmTaKktZdbuvcVGTg9bUT5kQaufwUtZ6e"
+	rootCID = "zdpuAkgGmUp5JrXvehGuuw9JA8DLQKDaxtK3R8brDQQVC2i5X"
 )
 
 func TestConstructors(t *testing.T) {
@@ -86,7 +88,7 @@ func TestConstructors(t *testing.T) {
 	require.NoError(t, err)
 
 	t.Run("New", func(t *testing.T) {
-		dlg, err := delegation.New(privKey, aud, cmd, pol,
+		tkn, err := delegation.New(privKey, aud, cmd, pol,
 			delegation.WithNonce([]byte(nonce)),
 			delegation.WithSubject(sub),
 			delegation.WithExpiration(exp),
@@ -95,7 +97,7 @@ func TestConstructors(t *testing.T) {
 		)
 		require.NoError(t, err)
 
-		data, err := dlg.ToDagJson(privKey)
+		data, err := tkn.ToDagJson(privKey)
 		require.NoError(t, err)
 
 		t.Log(string(data))
@@ -106,7 +108,7 @@ func TestConstructors(t *testing.T) {
 	t.Run("Root", func(t *testing.T) {
 		t.Parallel()
 
-		dlg, err := delegation.Root(privKey, aud, cmd, pol,
+		tkn, err := delegation.Root(privKey, aud, cmd, pol,
 			delegation.WithNonce([]byte(nonce)),
 			delegation.WithExpiration(exp),
 			delegation.WithMeta("foo", "fooo"),
@@ -114,7 +116,7 @@ func TestConstructors(t *testing.T) {
 		)
 		require.NoError(t, err)
 
-		data, err := dlg.ToDagJson(privKey)
+		data, err := tkn.ToDagJson(privKey)
 		require.NoError(t, err)
 
 		t.Log(string(data))
@@ -123,9 +125,7 @@ func TestConstructors(t *testing.T) {
 	})
 }
 
-func privKey(t *testing.T, privKeyCfg string) crypto.PrivKey {
-	t.Helper()
-
+func privKey(t require.TestingT, privKeyCfg string) crypto.PrivKey {
 	privKeyMar, err := crypto.ConfigDecodeKey(privKeyCfg)
 	require.NoError(t, err)
 
@@ -134,23 +134,3 @@ func privKey(t *testing.T, privKeyCfg string) crypto.PrivKey {
 
 	return privKey
 }
-
-func TestKey(t *testing.T) {
-	// TODO: why is this broken?
-	t.Skip("TODO: why is this broken?")
-
-	priv, _, err := crypto.GenerateEd25519Key(rand.Reader)
-	require.NoError(t, err)
-
-	privMar, err := crypto.MarshalPrivateKey(priv)
-	require.NoError(t, err)
-
-	privCfg := crypto.ConfigEncodeKey(privMar)
-	t.Log(privCfg)
-
-	id, err := did.FromPubKey(priv.GetPublic())
-	require.NoError(t, err)
-	t.Log(id)
-
-	t.Fail()
-}

tokens/delegation/ipld.go

@@ -3,6 +3,7 @@ package delegation
 import (
 	"io"
 
+	"github.com/ipfs/go-cid"
 	"github.com/ipld/go-ipld-prime"
 	"github.com/ipld/go-ipld-prime/codec"
 	"github.com/ipld/go-ipld-prime/codec/dagcbor"
@@ -11,13 +12,80 @@ import (
 	"github.com/libp2p/go-libp2p/core/crypto"
 
 	"github.com/ucan-wg/go-ucan/did"
-	"github.com/ucan-wg/go-ucan/internal/envelope"
+	"github.com/ucan-wg/go-ucan/tokens/internal/envelope"
 )
 
+// ToSealed wraps the delegation token in an envelope, generates the
+// signature, encodes the result to DAG-CBOR and calculates the CID of
+// the resulting binary data.
+func (t *Token) ToSealed(privKey crypto.PrivKey) ([]byte, cid.Cid, error) {
+	data, err := t.ToDagCbor(privKey)
+	if err != nil {
+		return nil, cid.Undef, err
+	}
+
+	id, err := envelope.CIDFromBytes(data)
+	if err != nil {
+		return nil, cid.Undef, err
+	}
+
+	return data, id, nil
+}
+
+// ToSealedWriter is the same as Seal but accepts an io.Writer.
+func (t *Token) ToSealedWriter(w io.Writer, privKey crypto.PrivKey) (cid.Cid, error) {
+	cidWriter := envelope.NewCIDWriter(w)
+
+	if err := t.ToDagCborWriter(cidWriter, privKey); err != nil {
+		return cid.Undef, err
+	}
+
+	return cidWriter.CID()
+}
+
+// FromSealed decodes the provided binary data from the DAG-CBOR format,
+// verifies that the envelope's signature is correct based on the public
+// key taken from the issuer (iss) field and calculates the CID of the
+// incoming data.
+func FromSealed(data []byte) (*Token, error) {
+	tkn, err := FromDagCbor(data)
+	if err != nil {
+		return nil, err
+	}
+
+	id, err := envelope.CIDFromBytes(data)
+	if err != nil {
+		return nil, err
+	}
+
+	tkn.cid = id
+
+	return tkn, nil
+}
+
+// FromSealedReader is the same as Unseal but accepts an io.Reader.
+func FromSealedReader(r io.Reader) (*Token, error) {
+	cidReader := envelope.NewCIDReader(r)
+
+	tkn, err := FromDagCborReader(cidReader)
+	if err != nil {
+		return nil, err
+	}
+
+	id, err := cidReader.CID()
+	if err != nil {
+		return nil, err
+	}
+
+	tkn.cid = id
+
+	return tkn, nil
+}
+
 // Encode marshals a View to the format specified by the provided
 // codec.Encoder.
 func (t *Token) Encode(privKey crypto.PrivKey, encFn codec.Encoder) ([]byte, error) {
-	node, err := t.ToIPLD(privKey)
+	node, err := t.toIPLD(privKey)
 	if err != nil {
 		return nil, err
 	}
@@ -27,7 +95,7 @@ func (t *Token) Encode(privKey crypto.PrivKey, encFn codec.Encoder) ([]byte, err
 
 // EncodeWriter is the same as Encode but accepts an io.Writer.
 func (t *Token) EncodeWriter(w io.Writer, privKey crypto.PrivKey, encFn codec.Encoder) error {
-	node, err := t.ToIPLD(privKey)
+	node, err := t.toIPLD(privKey)
 	if err != nil {
 		return err
 	}
@@ -55,9 +123,81 @@ func (t *Token) ToDagJsonWriter(w io.Writer, privKey crypto.PrivKey) error {
 	return t.EncodeWriter(w, privKey, dagjson.Encode)
 }
 
-// ToIPLD wraps the View in an IPLD datamodel.Node.
-func (t *Token) ToIPLD(privKey crypto.PrivKey) (datamodel.Node, error) {
+// Decode unmarshals the input data using the format specified by the
+// provided codec.Decoder into a View.
+//
+// An error is returned if the conversion fails, or if the resulting
+// View is invalid.
+func Decode(b []byte, decFn codec.Decoder) (*Token, error) {
+	node, err := ipld.Decode(b, decFn)
+	if err != nil {
+		return nil, err
+	}
+	return fromIPLD(node)
+}
+
+// DecodeReader is the same as Decode, but accept an io.Reader.
+func DecodeReader(r io.Reader, decFn codec.Decoder) (*Token, error) {
+	node, err := ipld.DecodeStreaming(r, decFn)
+	if err != nil {
+		return nil, err
+	}
+	return fromIPLD(node)
+}
+
+// FromDagCbor unmarshals the input data into a View.
+//
+// An error is returned if the conversion fails, or if the resulting
+// View is invalid.
+func FromDagCbor(data []byte) (*Token, error) {
+	pay, err := envelope.FromDagCbor[*tokenPayloadModel](data)
+	if err != nil {
+		return nil, err
+	}
+
+	tkn, err := tokenFromModel(*pay)
+	if err != nil {
+		return nil, err
+	}
+
+	return tkn, err
+}
+
+// FromDagCborReader is the same as FromDagCbor, but accept an io.Reader.
+func FromDagCborReader(r io.Reader) (*Token, error) {
+	return DecodeReader(r, dagcbor.Decode)
+}
+
+// FromDagJson unmarshals the input data into a View.
+//
+// An error is returned if the conversion fails, or if the resulting
+// View is invalid.
+func FromDagJson(data []byte) (*Token, error) {
+	return Decode(data, dagjson.Decode)
+}
+
+// FromDagJsonReader is the same as FromDagJson, but accept an io.Reader.
+func FromDagJsonReader(r io.Reader) (*Token, error) {
+	return DecodeReader(r, dagjson.Decode)
+}
+
+func fromIPLD(node datamodel.Node) (*Token, error) {
+	pay, err := envelope.FromIPLD[*tokenPayloadModel](node)
+	if err != nil {
+		return nil, err
+	}
+
+	tkn, err := tokenFromModel(*pay)
+	if err != nil {
+		return nil, err
+	}
+
+	return tkn, err
+}
+
+func (t *Token) toIPLD(privKey crypto.PrivKey) (datamodel.Node, error) {
 	var sub *string
+
 	if t.subject != did.Undef {
 		s := t.subject.String()
 		sub = &s
@@ -94,64 +234,3 @@ func (t *Token) ToIPLD(privKey crypto.PrivKey) (datamodel.Node, error) {
 
 	return envelope.ToIPLD(privKey, model)
 }
-
-// Decode unmarshals the input data using the format specified by the
-// provided codec.Decoder into a View.
-//
-// An error is returned if the conversion fails, or if the resulting
-// View is invalid.
-func Decode(b []byte, decFn codec.Decoder) (*Token, error) {
-	node, err := ipld.Decode(b, decFn)
-	if err != nil {
-		return nil, err
-	}
-	return FromIPLD(node)
-}
-
-// DecodeReader is the same as Decode, but accept an io.Reader.
-func DecodeReader(r io.Reader, decFn codec.Decoder) (*Token, error) {
-	node, err := ipld.DecodeStreaming(r, decFn)
-	if err != nil {
-		return nil, err
-	}
-	return FromIPLD(node)
-}
-
-// FromDagCbor unmarshals the input data into a View.
-//
-// An error is returned if the conversion fails, or if the resulting
-// View is invalid.
-func FromDagCbor(data []byte) (*Token, error) {
-	return Decode(data, dagcbor.Decode)
-}
-
-// FromDagCborReader is the same as FromDagCbor, but accept an io.Reader.
-func FromDagCborReader(r io.Reader) (*Token, error) {
-	return DecodeReader(r, dagcbor.Decode)
-}
-
-// FromDagJson unmarshals the input data into a View.
-//
-// An error is returned if the conversion fails, or if the resulting
-// View is invalid.
-func FromDagJson(data []byte) (*Token, error) {
-	return Decode(data, dagjson.Decode)
-}
-
-// FromDagJsonReader is the same as FromDagJson, but accept an io.Reader.
-func FromDagJsonReader(r io.Reader) (*Token, error) {
-	return DecodeReader(r, dagjson.Decode)
-}
-
-// FromIPLD unwraps a View from the provided IPLD datamodel.Node
-//
-// An error is returned if the conversion fails, or if the resulting
-// View is invalid.
-func FromIPLD(node datamodel.Node) (*Token, error) {
-	tkn, _, err := envelope.FromIPLD[*tokenPayloadModel](node) // TODO add CID to view
-	if err != nil {
-		return nil, err
-	}
-
-	return tokenFromModel(*tkn)
-}

tokens/delegation/options.go

@@ -0,0 +1,72 @@
+package delegation
+
+import (
+	"fmt"
+	"time"
+
+	"github.com/ucan-wg/go-ucan/did"
+)
+
+// Option is a type that allows optional fields to be set during the
+// creation of a Token.
+type Option func(*Token) error
+
+// WithExpiration set's the Token's optional "expiration" field to the
+// value of the provided time.Time.
+func WithExpiration(exp time.Time) Option {
+	return func(t *Token) error {
+		if exp.Before(time.Now()) {
+			return fmt.Errorf("a Token's expiration should be set to a time in the future: %s", exp.String())
+		}
+
+		t.expiration = &exp
+		return nil
+	}
+}
+
+// WithMeta adds a key/value pair in the "meta" field.
+//
+// WithMeta can be used multiple times in the same call.
+// Accepted types for the value are: bool, string, int, int32, int64, []byte,
+// and ipld.Node.
+func WithMeta(key string, val any) Option {
+	return func(t *Token) error {
+		return t.meta.Add(key, val)
+	}
+}
+
+// WithNotBefore set's the Token's optional "notBefore" field to the value
+// of the provided time.Time.
+func WithNotBefore(nbf time.Time) Option {
+	return func(t *Token) error {
+		if nbf.Before(time.Now()) {
+			return fmt.Errorf("a Token's \"not before\" field should be set to a time in the future: %s", nbf.String())
+		}
+
+		t.notBefore = &nbf
+		return nil
+	}
+}
+
+// WithSubject sets the Tokens's optional "subject" field to the value of
+// provided did.DID.
+//
+// This Option should only be used with the New constructor - since
+// Subject is a required parameter when creating a Token via the  Root
+// constructor, any value provided via this Option will be silently
+// overwritten.
+func WithSubject(sub did.DID) Option {
+	return func(t *Token) error {
+		t.subject = sub
+		return nil
+	}
+}
+
+// WithNonce sets the Token's nonce with the given value.
+// If this option is not used, a random 12-byte nonce is generated for this required field.
+func WithNonce(nonce []byte) Option {
+	return func(t *Token) error {
+		t.nonce = nonce
+		return nil
+	}
+}

tokens/delegation/schema.go

@@ -10,12 +10,18 @@ import (
 	"github.com/ipld/go-ipld-prime/node/bindnode"
 	"github.com/ipld/go-ipld-prime/schema"
 
-	"github.com/ucan-wg/go-ucan/internal/envelope"
 	"github.com/ucan-wg/go-ucan/pkg/meta"
+	"github.com/ucan-wg/go-ucan/tokens/internal/envelope"
 )
 
+// [Tag] is the string used as a key within the SigPayload that identifies
+// that the TokenPayload is a delegation.
+//
+// [Tag]: https://github.com/ucan-wg/delegation/tree/v1_ipld#type-tag
 const Tag = "ucan/dlg@1.0.0-rc.1"
 
+// TODO: update the above Tag URL once the delegation specification is merged.
+
 //go:embed delegation.ipldsch
 var schemaBytes []byte
 

tokens/delegation/schema_test.go

@@ -0,0 +1,177 @@
+package delegation_test
+
+import (
+	"bytes"
+	_ "embed"
+	"fmt"
+	"testing"
+
+	"github.com/ipld/go-ipld-prime"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"gotest.tools/v3/golden"
+
+	"github.com/ucan-wg/go-ucan/tokens/delegation"
+	"github.com/ucan-wg/go-ucan/tokens/internal/envelope"
+)
+
+//go:embed delegation.ipldsch
+var schemaBytes []byte
+
+func TestSchemaRoundTrip(t *testing.T) {
+	t.Parallel()
+
+	delegationJson := golden.Get(t, "new.dagjson")
+	privKey := privKey(t, issuerPrivKeyCfg)
+
+	t.Run("via buffers", func(t *testing.T) {
+		t.Parallel()
+
+		// format:    dagJson   -->   PayloadModel   -->   dagCbor   -->   PayloadModel   -->   dagJson
+		// function:      DecodeDagJson()           Seal()        Unseal()          EncodeDagJson()
+
+		p1, err := delegation.FromDagJson(delegationJson)
+		require.NoError(t, err)
+
+		cborBytes, id, err := p1.ToSealed(privKey)
+		require.NoError(t, err)
+		assert.Equal(t, newCID, envelope.CIDToBase58BTC(id))
+		fmt.Println("cborBytes length", len(cborBytes))
+		fmt.Println("cbor", string(cborBytes))
+
+		p2, err := delegation.FromSealed(cborBytes)
+		require.NoError(t, err)
+		assert.Equal(t, id, p2.CID())
+		fmt.Println("read Cbor", p2)
+
+		readJson, err := p2.ToDagJson(privKey)
+		require.NoError(t, err)
+		fmt.Println("readJson length", len(readJson))
+		fmt.Println("json: ", string(readJson))
+
+		assert.JSONEq(t, string(delegationJson), string(readJson))
+	})
+
+	t.Run("via streaming", func(t *testing.T) {
+		t.Parallel()
+
+		buf := bytes.NewBuffer(delegationJson)
+
+		// format:    dagJson   -->   PayloadModel   -->   dagCbor   -->   PayloadModel   -->   dagJson
+		// function:      DecodeDagJson()           Seal()         Unseal()         EncodeDagJson()
+
+		p1, err := delegation.FromDagJsonReader(buf)
+		require.NoError(t, err)
+
+		cborBytes := &bytes.Buffer{}
+		id, err := p1.ToSealedWriter(cborBytes, privKey)
+		t.Log(len(id.Bytes()), id.Bytes())
+		require.NoError(t, err)
+		assert.Equal(t, newCID, envelope.CIDToBase58BTC(id))
+
+		// buf = bytes.NewBuffer(cborBytes.Bytes())
+		p2, err := delegation.FromSealedReader(cborBytes)
+		require.NoError(t, err)
+		t.Log(len(p2.CID().Bytes()), p2.CID().Bytes())
+		assert.Equal(t, envelope.CIDToBase58BTC(id), envelope.CIDToBase58BTC(p2.CID()))
+
+		readJson := &bytes.Buffer{}
+		require.NoError(t, p2.ToDagJsonWriter(readJson, privKey))
+
+		assert.JSONEq(t, string(delegationJson), readJson.String())
+	})
+}
+
+func BenchmarkSchemaLoad(b *testing.B) {
+	b.ReportAllocs()
+	for i := 0; i < b.N; i++ {
+		_, _ = ipld.LoadSchemaBytes(schemaBytes)
+	}
+}
+
+func BenchmarkRoundTrip(b *testing.B) {
+	delegationJson := golden.Get(b, "new.dagjson")
+	privKey := privKey(b, issuerPrivKeyCfg)
+
+	b.Run("via buffers", func(b *testing.B) {
+		p1, _ := delegation.FromDagJson(delegationJson)
+		cborBytes, _, _ := p1.ToSealed(privKey)
+		p2, _ := delegation.FromSealed(cborBytes)
+
+		b.ResetTimer()
+
+		b.Run("FromDagJson", func(b *testing.B) {
+			b.ReportAllocs()
+			for i := 0; i < b.N; i++ {
+				_, _ = delegation.FromDagJson(delegationJson)
+			}
+		})
+
+		b.Run("Seal", func(b *testing.B) {
+			b.ReportAllocs()
+			for i := 0; i < b.N; i++ {
+				_, _, _ = p1.ToSealed(privKey)
+			}
+		})
+
+		b.Run("Unseal", func(b *testing.B) {
+			b.ReportAllocs()
+			for i := 0; i < b.N; i++ {
+				_, _ = delegation.FromSealed(cborBytes)
+			}
+		})
+
+		b.Run("ToDagJson", func(b *testing.B) {
+			b.ReportAllocs()
+			for i := 0; i < b.N; i++ {
+				_, _ = p2.ToDagJson(privKey)
+			}
+		})
+	})
+
+	b.Run("via streaming", func(b *testing.B) {
+		p1, _ := delegation.FromDagJsonReader(bytes.NewReader(delegationJson))
+		cborBuf := &bytes.Buffer{}
+		_, _ = p1.ToSealedWriter(cborBuf, privKey)
+		cborBytes := cborBuf.Bytes()
+		p2, _ := delegation.FromSealedReader(bytes.NewReader(cborBytes))
+
+		b.ResetTimer()
+
+		b.Run("FromDagJsonReader", func(b *testing.B) {
+			b.ReportAllocs()
+			reader := bytes.NewReader(delegationJson)
+			for i := 0; i < b.N; i++ {
+				_, _ = reader.Seek(0, 0)
+				_, _ = delegation.FromDagJsonReader(reader)
+			}
+		})
+
+		b.Run("SealWriter", func(b *testing.B) {
+			b.ReportAllocs()
+			buf := &bytes.Buffer{}
+			for i := 0; i < b.N; i++ {
+				buf.Reset()
+				_, _ = p1.ToSealedWriter(buf, privKey)
+			}
+		})
+
+		b.Run("UnsealReader", func(b *testing.B) {
+			b.ReportAllocs()
+			reader := bytes.NewReader(cborBytes)
+			for i := 0; i < b.N; i++ {
+				_, _ = reader.Seek(0, 0)
+				_, _ = delegation.FromSealedReader(reader)
+			}
+		})
+
+		b.Run("ToDagJsonReader", func(b *testing.B) {
+			b.ReportAllocs()
+			buf := &bytes.Buffer{}
+			for i := 0; i < b.N; i++ {
+				buf.Reset()
+				_ = p2.ToDagJsonWriter(buf, privKey)
+			}
+		})
+	})
+}

tokens/internal/envelope/cid.go

@@ -0,0 +1,124 @@
+package envelope
+
+import (
+	"crypto/sha256"
+	"hash"
+	"io"
+
+	"github.com/ipfs/go-cid"
+	"github.com/multiformats/go-multibase"
+	"github.com/multiformats/go-multicodec"
+	"github.com/multiformats/go-multihash"
+)
+
+var b58BTCEnc = multibase.MustNewEncoder(multibase.Base58BTC)
+
+// CIDToBase56BTC is a utility method to convert a CIDv1 to the canonical
+// string representation used by UCAN.
+func CIDToBase58BTC(id cid.Cid) string {
+	return id.Encode(b58BTCEnc)
+}
+
+// CIDFromBytes returns the UCAN content identifier for an arbitrary slice
+// of bytes.
+func CIDFromBytes(b []byte) (cid.Cid, error) {
+	return cid.V1Builder{
+		Codec:    uint64(multicodec.DagCbor),
+		MhType:   multihash.SHA2_256,
+		MhLength: 0,
+	}.Sum(b)
+}
+
+var _ io.Reader = (*CIDReader)(nil)
+
+// CIDReader wraps an io.Reader and includes a hash.Hash that is
+// incrementally updated as data is read from the child io.Reader.
+type CIDReader struct {
+	hash hash.Hash
+	r    io.Reader
+	err  error
+}
+
+// NewCIDReader initializes a hash.Hash to calculate the CID's hash and
+// returns the wrapped io.Reader.
+func NewCIDReader(r io.Reader) *CIDReader {
+	h := sha256.New()
+	h.Reset()
+
+	return &CIDReader{
+		hash: h,
+		r:    r,
+	}
+}
+
+// CID returns the UCAN-formatted cid.Cid created from the hash calculated
+// as bytes were read from the inner io.Reader.
+func (r *CIDReader) CID() (cid.Cid, error) {
+	if r.err != nil {
+		return cid.Undef, r.err // TODO: Wrap to say it's an error during streaming?
+	}
+
+	return cidFromHash(r.hash)
+}
+
+// Read implements io.Reader.
+func (r *CIDReader) Read(p []byte) (n int, err error) {
+	n, err = r.r.Read(p)
+	if err != nil && err != io.EOF {
+		r.err = err
+
+		return
+	}
+
+	_, _ = r.hash.Write(p[:n])
+
+	return
+}
+
+var _ io.Writer = (*CIDWriter)(nil)
+
+// CIDWriter wraps an io.Writer and includes a hash.Hash that is
+// incrementally updated as data is written to the child io.Writer.
+type CIDWriter struct {
+	hash hash.Hash
+	w    io.Writer
+	err  error
+}
+
+// NewCIDWriter initializes a hash.Hash to calculate the CID's hash and
+// returns the wrapped io.Writer.
+func NewCIDWriter(w io.Writer) *CIDWriter {
+	h := sha256.New()
+	h.Reset()
+
+	return &CIDWriter{
+		hash: h,
+		w:    w,
+	}
+}
+
+// CID returns the UCAN-formatted cid.Cid created from the hash calculated
+// as bytes were written from the inner io.Reader.
+func (w *CIDWriter) CID() (cid.Cid, error) {
+	return cidFromHash(w.hash)
+}
+
+// Write implements io.Writer.
+func (w *CIDWriter) Write(p []byte) (n int, err error) {
+	if _, err = w.hash.Write(p); err != nil {
+		w.err = err
+
+		return
+	}
+
+	return w.w.Write(p)
+}
+
+func cidFromHash(hash hash.Hash) (cid.Cid, error) {
+	mh, err := multihash.Encode(hash.Sum(nil), multihash.SHA2_256)
+	if err != nil {
+		return cid.Undef, err
+	}
+
+	return cid.NewCidV1(uint64(multicodec.DagCbor), mh), nil
+}

tokens/internal/envelope/cid_test.go

@@ -0,0 +1,86 @@
+package envelope_test
+
+import (
+	"io"
+	"testing"
+
+	"github.com/ipfs/go-cid"
+	"github.com/multiformats/go-multicodec"
+	"github.com/multiformats/go-multihash"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"gotest.tools/v3/golden"
+
+	"github.com/ucan-wg/go-ucan/tokens/internal/envelope"
+)
+
+func TestCidFromBytes(t *testing.T) {
+	t.Parallel()
+
+	expData := golden.Get(t, "example.dagcbor")
+	expHash, err := multihash.Sum(expData, uint64(multicodec.Sha2_256), -1)
+	require.NoError(t, err)
+
+	data, err := envelope.ToDagCbor(examplePrivKey(t), newExample(t))
+	require.NoError(t, err)
+
+	id, err := envelope.CIDFromBytes(data)
+	require.NoError(t, err)
+	assert.Equal(t, exampleCID, envelope.CIDToBase58BTC(id))
+	assert.Equal(t, expHash, id.Hash())
+}
+
+func TestStreaming(t *testing.T) {
+	t.Parallel()
+
+	expData := []byte("this is a test")
+
+	expCID, err := cid.V1Builder{
+		Codec:    uint64(multicodec.DagCbor),
+		MhType:   multihash.SHA2_256,
+		MhLength: 0,
+	}.Sum(expData)
+	require.NoError(t, err)
+
+	t.Run("CIDReader()", func(t *testing.T) {
+		t.Parallel()
+
+		r, w := io.Pipe() //nolint:varnamelen
+		cidReader := envelope.NewCIDReader(r)
+
+		go func() {
+			_, err := w.Write(expData)
+			assert.NoError(t, err)
+			assert.NoError(t, w.Close())
+		}()
+
+		actData, err := io.ReadAll(cidReader)
+		require.NoError(t, err)
+		assert.Equal(t, expData, actData)
+
+		actCID, err := cidReader.CID()
+		require.NoError(t, err)
+		assert.Equal(t, expCID, actCID)
+	})
+
+	t.Run("CIDWriter", func(t *testing.T) {
+		t.Parallel()
+
+		r, w := io.Pipe() //nolint:varnamelen
+		cidWriter := envelope.NewCIDWriter(w)
+
+		go func() {
+			_, err := cidWriter.Write(expData)
+			assert.NoError(t, err)
+			assert.NoError(t, w.Close())
+		}()
+
+		actData, err := io.ReadAll(r)
+		require.NoError(t, err)
+		assert.Equal(t, expData, actData)
+
+		actCID, err := cidWriter.CID()
+		require.NoError(t, err)
+		assert.Equal(t, expCID, actCID)
+	})
+}

tokens/internal/envelope/example_test.go

@@ -16,11 +16,12 @@ import (
 	"github.com/ipld/go-ipld-prime/schema"
 	"github.com/libp2p/go-libp2p/core/crypto"
 	"github.com/stretchr/testify/require"
-	"github.com/ucan-wg/go-ucan/internal/envelope"
+	"github.com/ucan-wg/go-ucan/tokens/internal/envelope"
 	"gotest.tools/v3/golden"
 )
 
 const (
+	exampleCID             = "zdpuAyw6R5HvKSPzztuzXNYFx3ZGoMHMuAsXL6u3xLGQriRXQ"
 	exampleDID             = "did:key:z6MkpuK2Amsu1RqcLGgmHHQHhvmeXCCBVsM4XFSg2cCyg4Nh"
 	exampleGreeting        = "world"
 	examplePrivKeyCfg      = "CAESQP9v2uqECTuIi45dyg3znQvsryvf2IXmOF/6aws6aCehm0FVrj0zHR5RZSDxWNjcpcJqsGym3sjCungX9Zt5oA4="

tokens/internal/envelope/ipld.go

@@ -8,8 +8,7 @@
 //
 // Decoding functions in this package likewise perform the signature
 // verification using a public key extracted from the TokenPayload as
-// described by requirement two below.  Additionally, the decode functions
-// also return the CID for the verified Envelope.
+// described by requirement two below.
 //
 // Types that wish to be marshaled and unmarshaled from the using
 // is package have two requirements.
@@ -30,7 +29,6 @@ import (
 	"errors"
 	"io"
 
-	"github.com/ipfs/go-cid"
 	"github.com/ipld/go-ipld-prime"
 	"github.com/ipld/go-ipld-prime/codec"
 	"github.com/ipld/go-ipld-prime/codec/dagcbor"
@@ -41,8 +39,9 @@ import (
 	"github.com/ipld/go-ipld-prime/node/bindnode"
 	"github.com/ipld/go-ipld-prime/schema"
 	"github.com/libp2p/go-libp2p/core/crypto"
+
 	"github.com/ucan-wg/go-ucan/did"
-	"github.com/ucan-wg/go-ucan/internal/varsig"
+	"github.com/ucan-wg/go-ucan/tokens/internal/varsig"
 )
 
 const varsigHeaderKey = "h"
@@ -66,20 +65,20 @@ type Tokener interface {
 //
 // An error is returned if the conversion fails, or if the resulting
 // Tokener is invalid.
-func Decode[T Tokener](b []byte, decFn codec.Decoder) (T, cid.Cid, error) {
+func Decode[T Tokener](b []byte, decFn codec.Decoder) (T, error) {
 	node, err := ipld.Decode(b, decFn)
 	if err != nil {
-		return *new(T), cid.Undef, err
+		return *new(T), err
 	}
 
 	return FromIPLD[T](node)
 }
 
 // DecodeReader is the same as Decode, but accept an io.Reader.
-func DecodeReader[T Tokener](r io.Reader, decFn codec.Decoder) (T, cid.Cid, error) {
+func DecodeReader[T Tokener](r io.Reader, decFn codec.Decoder) (T, error) {
 	node, err := ipld.DecodeStreaming(r, decFn)
 	if err != nil {
-		return *new(T), cid.Undef, err
+		return *new(T), err
 	}
 
 	return FromIPLD[T](node)
@@ -89,12 +88,24 @@ func DecodeReader[T Tokener](r io.Reader, decFn codec.Decoder) (T, cid.Cid, erro
 //
 // An error is returned if the conversion fails, or if the resulting
 // Tokener is invalid.
-func FromDagCbor[T Tokener](b []byte) (T, cid.Cid, error) {
-	return Decode[T](b, dagcbor.Decode)
+func FromDagCbor[T Tokener](b []byte) (T, error) {
+	undef := *new(T)
+
+	node, err := ipld.Decode(b, dagcbor.Decode)
+	if err != nil {
+		return undef, err
+	}
+
+	tkn, err := fromIPLD[T](node)
+	if err != nil {
+		return undef, err
+	}
+
+	return tkn, nil
 }
 
 // FromDagCborReader is the same as FromDagCbor, but accept an io.Reader.
-func FromDagCborReader[T Tokener](r io.Reader) (T, cid.Cid, error) {
+func FromDagCborReader[T Tokener](r io.Reader) (T, error) {
 	return DecodeReader[T](r, dagcbor.Decode)
 }
 
@@ -102,12 +113,12 @@ func FromDagCborReader[T Tokener](r io.Reader) (T, cid.Cid, error) {
 //
 // An error is returned if the conversion fails, or if the resulting
 // Tokener is invalid.
-func FromDagJson[T Tokener](b []byte) (T, cid.Cid, error) {
+func FromDagJson[T Tokener](b []byte) (T, error) {
 	return Decode[T](b, dagjson.Decode)
 }
 
 // FromDagJsonReader is the same as FromDagJson, but accept an io.Reader.
-func FromDagJsonReader[T Tokener](r io.Reader) (T, cid.Cid, error) {
+func FromDagJsonReader[T Tokener](r io.Reader) (T, error) {
 	return DecodeReader[T](r, dagjson.Decode)
 }
 
@@ -115,111 +126,117 @@ func FromDagJsonReader[T Tokener](r io.Reader) (T, cid.Cid, error) {
 //
 // An error is returned if the conversion fails, or if the resulting
 // Tokener is invalid.
-func FromIPLD[T Tokener](node datamodel.Node) (T, cid.Cid, error) {
+func FromIPLD[T Tokener](node datamodel.Node) (T, error) {
+	undef := *new(T)
+
+	tkn, err := fromIPLD[T](node)
+	if err != nil {
+		return undef, err
+	}
+
+	return tkn, nil
+}
+
+func fromIPLD[T Tokener](node datamodel.Node) (T, error) {
 	undef := *new(T)
 
 	signatureNode, err := node.LookupByIndex(0)
 	if err != nil {
-		return undef, cid.Undef, err
+		return undef, err
 	}
 
 	signature, err := signatureNode.AsBytes()
 	if err != nil {
-		return undef, cid.Undef, err
+		return undef, err
 	}
 
 	sigPayloadNode, err := node.LookupByIndex(1)
 	if err != nil {
-		return undef, cid.Undef, err
+		return undef, err
 	}
 
 	varsigHeaderNode, err := sigPayloadNode.LookupByString(varsigHeaderKey)
 	if err != nil {
-		return undef, cid.Undef, err
+		return undef, err
 	}
 
 	tokenPayloadNode, err := sigPayloadNode.LookupByString(undef.Tag())
 	if err != nil {
-		return undef, cid.Undef, err
+		return undef, err
 	}
 
-	// This needs to be done before converting this node to it's schema
+	// This needs to be done before converting this node to its schema
 	// representation (afterwards, the field might be renamed os it's safer
 	// to use the wire name).
 	issuerNode, err := tokenPayloadNode.LookupByString("iss")
 	if err != nil {
-		return undef, cid.Undef, err
+		return undef, err
 	}
-	// ^^^
 
 	// Replaces the datamodel.Node in tokenPayloadNode with a
 	// schema.TypedNode so that we can cast it to a *token.Token after
 	// unwrapping it.
-	// vvv
 	nb := undef.Prototype().Representation().NewBuilder()
 
 	err = nb.AssignNode(tokenPayloadNode)
 	if err != nil {
-		return undef, cid.Undef, err
+		return undef, err
 	}
 
 	tokenPayloadNode = nb.Build()
-	// ^^^
 
 	tokenPayload := bindnode.Unwrap(tokenPayloadNode)
 	if tokenPayload == nil {
-		return undef, cid.Undef, errors.New("failed to Unwrap the TokenPayload")
+		return undef, errors.New("failed to Unwrap the TokenPayload")
 	}
 
 	tkn, ok := tokenPayload.(T)
 	if !ok {
-		return undef, cid.Undef, errors.New("failed to assert the TokenPayload type as *token.Token")
+		return undef, errors.New("failed to assert the TokenPayload type as *token.Token")
 	}
 
 	// Check that the issuer's DID contains a public key with a type that
 	// matches the VarsigHeader and then verify the SigPayload.
-	// vvv
 	issuer, err := issuerNode.AsString()
 	if err != nil {
-		return undef, cid.Undef, err
+		return undef, err
 	}
 
 	issuerDID, err := did.Parse(issuer)
 	if err != nil {
-		return undef, cid.Undef, err
+		return undef, err
 	}
 
 	issuerPubKey, err := issuerDID.PubKey()
 	if err != nil {
-		return undef, cid.Undef, err
+		return undef, err
 	}
 
 	issuerVarsigHeader, err := varsig.Encode(issuerPubKey.Type())
 	if err != nil {
-		return undef, cid.Undef, err
+		return undef, err
 	}
 
 	varsigHeader, err := varsigHeaderNode.AsBytes()
 	if err != nil {
-		return undef, cid.Undef, err
+		return undef, err
 	}
 
 	if string(varsigHeader) != string(issuerVarsigHeader) {
-		return undef, cid.Undef, errors.New("the VarsigHeader key type doesn't match the issuer's key type")
+		return undef, errors.New("the VarsigHeader key type doesn't match the issuer's key type")
 	}
 
 	data, err := ipld.Encode(sigPayloadNode, dagcbor.Encode)
 	if err != nil {
-		return undef, cid.Undef, err
+		return undef, err
 	}
 
 	ok, err = issuerPubKey.Verify(data, signature)
 	if err != nil || !ok {
-		return undef, cid.Undef, errors.New("failed to verify the token's signature")
+		return undef, errors.New("failed to verify the token's signature")
 	}
-	// ^^^
 
-	return tkn, cid.Undef, nil
+	return tkn, nil
 }
 
 // Encode marshals a Tokener to the format specified by the provided

tokens/internal/envelope/ipld_test.go

@@ -2,11 +2,12 @@ package envelope_test
 
 import (
 	"bytes"
+	"crypto/sha256"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
-	"github.com/ucan-wg/go-ucan/internal/envelope"
+	"github.com/ucan-wg/go-ucan/tokens/internal/envelope"
 	"gotest.tools/v3/golden"
 )
 
@@ -18,7 +19,7 @@ func TestDecode(t *testing.T) {
 
 		data := golden.Get(t, "example.dagcbor")
 
-		tkn, _, err := envelope.FromDagCbor[*Example](data)
+		tkn, err := envelope.FromDagCbor[*Example](data)
 		require.NoError(t, err)
 		assert.Equal(t, exampleGreeting, tkn.Hello)
 		assert.Equal(t, exampleDID, tkn.Issuer)
@@ -29,7 +30,7 @@ func TestDecode(t *testing.T) {
 
 		data := golden.Get(t, "example.dagjson")
 
-		tkn, _, err := envelope.FromDagJson[*Example](data)
+		tkn, err := envelope.FromDagJson[*Example](data)
 		require.NoError(t, err)
 		assert.Equal(t, exampleGreeting, tkn.Hello)
 		assert.Equal(t, exampleDID, tkn.Issuer)
@@ -59,12 +60,27 @@ func TestEncode(t *testing.T) {
 func TestRoundtrip(t *testing.T) {
 	t.Parallel()
 
+	t.Run("via FromDagCbor/ToDagCbor", func(t *testing.T) {
+		t.Parallel()
+
+		dataIn := golden.Get(t, exampleDAGCBORFilename)
+
+		tkn, err := envelope.FromDagCbor[*Example](dataIn)
+		require.NoError(t, err)
+		assert.Equal(t, exampleGreeting, tkn.Hello)
+		assert.Equal(t, exampleDID, tkn.Issuer)
+
+		dataOut, err := envelope.ToDagCbor(examplePrivKey(t), newExample(t))
+		require.NoError(t, err)
+		assert.Equal(t, dataIn, dataOut)
+	})
+
 	t.Run("via FromDagCborReader/ToDagCborWriter", func(t *testing.T) {
 		t.Parallel()
 
 		data := golden.Get(t, exampleDAGCBORFilename)
 
-		tkn, _, err := envelope.FromDagCborReader[*Example](bytes.NewReader(data))
+		tkn, err := envelope.FromDagCborReader[*Example](bytes.NewReader(data))
 		require.NoError(t, err)
 		assert.Equal(t, exampleGreeting, tkn.Hello)
 		assert.Equal(t, exampleDID, tkn.Issuer)
@@ -74,27 +90,62 @@ func TestRoundtrip(t *testing.T) {
 		assert.Equal(t, data, w.Bytes())
 	})
 
-	t.Run("via FromDagCbor/ToDagCbor", func(t *testing.T) {
+	t.Run("via FromDagJson/ToDagJson", func(t *testing.T) {
 		t.Parallel()
 
-		dataIn := golden.Get(t, exampleDAGCBORFilename)
+		dataIn := golden.Get(t, exampleDAGJSONFilename)
 
-		tkn, _, err := envelope.FromDagCbor[*Example](dataIn)
+		tkn, err := envelope.FromDagJson[*Example](dataIn)
 		require.NoError(t, err)
 		assert.Equal(t, exampleGreeting, tkn.Hello)
 		assert.Equal(t, exampleDID, tkn.Issuer)
 
-		dataOut, err := envelope.ToDagCbor(examplePrivKey(t), newExample(t))
+		dataOut, err := envelope.ToDagJson(examplePrivKey(t), newExample(t))
 		require.NoError(t, err)
 		assert.Equal(t, dataIn, dataOut)
 	})
+
+	t.Run("via FromDagJsonReader/ToDagJsonrWriter", func(t *testing.T) {
+		t.Parallel()
+
+		data := golden.Get(t, exampleDAGJSONFilename)
+
+		tkn, err := envelope.FromDagJsonReader[*Example](bytes.NewReader(data))
+		require.NoError(t, err)
+		assert.Equal(t, exampleGreeting, tkn.Hello)
+		assert.Equal(t, exampleDID, tkn.Issuer)
+
+		w := &bytes.Buffer{}
+		require.NoError(t, envelope.ToDagJsonWriter(w, examplePrivKey(t), newExample(t)))
+		assert.Equal(t, data, w.Bytes())
+	})
 }
 
 func TestFromIPLD_with_invalid_signature(t *testing.T) {
 	t.Parallel()
 
 	node := invalidNodeFromGolden(t)
-	tkn, _, err := envelope.FromIPLD[*Example](node)
+	tkn, err := envelope.FromIPLD[*Example](node)
 	assert.Nil(t, tkn)
 	require.EqualError(t, err, "failed to verify the token's signature")
 }
+
+func TestHash(t *testing.T) {
+	t.Parallel()
+
+	msg := []byte("this is a test")
+
+	hash1 := sha256.Sum256(msg)
+
+	hasher := sha256.New()
+
+	for _, b := range msg {
+		hasher.Write([]byte{b})
+	}
+
+	hash2 := hasher.Sum(nil)
+	hash3 := hasher.Sum(nil)
+
+	require.Equal(t, hash1[:], hash2)
+	require.Equal(t, hash1[:], hash3)
+}

tokens/internal/varsig/varsig_test.go

@@ -8,7 +8,7 @@ import (
 	"github.com/libp2p/go-libp2p/core/crypto/pb"
 	"github.com/stretchr/testify/assert"
 
-	"github.com/ucan-wg/go-ucan/internal/varsig"
+	"github.com/ucan-wg/go-ucan/tokens/internal/varsig"
 )
 
 func TestDecode(t *testing.T) {