feat(didkey): didkey package properly implements v0.7 of spec

.gitignore

@@ -0,0 +1 @@
+coverage.txt

didkey/key.go

@@ -0,0 +1,99 @@
+// Package didkey implements the did:key method. A DID Method for Static
+// Cryptographic Keys. From the w3c draft spec
+// https://w3c-ccg.github.io/did-method-key/
+package didkey
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/libp2p/go-libp2p-core/crypto"
+	mb "github.com/multiformats/go-multibase"
+	varint "github.com/multiformats/go-varint"
+)
+
+const (
+	// KeyPrefix indicates a decentralized identifier that uses the key method
+	KeyPrefix = "did:key"
+	// MulticodecKindRSAPubKey IS NOT A REAL MULTICODEC PREFIX.
+	// pulled from: https://github.com/w3c-ccg/lds-ed25519-2018/issues/3 because
+	// it's only slighly better than picking a random available byte prefix
+	MulticodecKindRSAPubKey = 0x5d
+	// MulticodecKindEd25519PubKey ed25519-pub
+	MulticodecKindEd25519PubKey = 0xed
+)
+
+// ID is a DID:key identifier
+type ID struct {
+	crypto.PubKey
+}
+
+// MulticodecType indicates the type for this multicodec
+func (id ID) MulticodecType() uint64 {
+	switch id.Type() {
+	case crypto.RSA:
+		return MulticodecKindRSAPubKey
+	case crypto.Ed25519:
+		return MulticodecKindEd25519PubKey
+	default:
+		panic("unexpected crypto type")
+	}
+}
+
+// String returns this did:key formatted as a string
+func (id ID) String() string {
+	raw, err := id.Raw()
+	if err != nil {
+		return ""
+	}
+
+	t := id.MulticodecType()
+	size := varint.UvarintSize(t)
+	data := make([]byte, size+len(raw))
+	n := varint.PutUvarint(data, t)
+	copy(data[n:], raw)
+
+	b58BKeyStr, err := mb.Encode(mb.Base58BTC, data)
+	if err != nil {
+		return ""
+	}
+
+	return fmt.Sprintf("%s:%s", KeyPrefix, b58BKeyStr)
+}
+
+// Parse turns a string into a key method ID
+func Parse(keystr string) (ID, error) {
+	var id ID
+	if !strings.HasPrefix(keystr, KeyPrefix) {
+		return id, fmt.Errorf("decentralized identifier is not a 'key' type")
+	}
+
+	keystr = strings.TrimPrefix(keystr, KeyPrefix+":")
+
+	_, data, err := mb.Decode(keystr)
+	if err != nil {
+		return id, err
+	}
+
+	keyType, n, err := varint.FromUvarint(data)
+	if err != nil {
+		return id, err
+	}
+
+	switch keyType {
+	case MulticodecKindRSAPubKey:
+		pub, err := crypto.UnmarshalRsaPublicKey(data[n:])
+		if err != nil {
+			return id, err
+		}
+		return ID{pub}, nil
+	case MulticodecKindEd25519PubKey:
+		pub, err := crypto.UnmarshalEd25519PublicKey(data[n:])
+		if err != nil {
+			return id, err
+		}
+		return ID{pub}, nil
+	}
+
+	return id, fmt.Errorf("unrecognized key type multicodec prefix: %x", data[0])
+}

didkey/key_test.go

@@ -0,0 +1,28 @@
+package didkey
+
+import (
+	"testing"
+)
+
+func TestID(t *testing.T) {
+	keyStrED := "did:key:z6MkpTHR8VNsBxYAAWHut2Geadd9jSwuBV8xRoAnwWsdvktH"
+	id, err := Parse(keyStrED)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if id.String() != keyStrED {
+		t.Errorf("string mismatch.\nwant: %q\ngot:  %q", keyStrED, id.String())
+	}
+
+	keyStrRSA := "did:key:zDQw3CC91XtvcBm5kY3FGBFgJarujMEKcarucbThDbGWVo3cAQPgvXuH5g9kxe9PNVHhAQpRQzTZQ3Pchra5pqKt6SgwTdgHXJtcWwp2pqkAmuNqhUj22naAg526RvU8u5ZE3tidrxh8zajWsrXriFwkVtZfTbEBGKewUMRVhttA3hc8Rpa6gL5HRqZ44Uq1fdKzdsBMTfG5ohhRzesiwoEtRyb3w4SPhdVYrD5Rd2KJPyTUqCvuuFwLAJJcDaPkp36RnRnFbbtZEydPtdMscnJTmj5nD9kpSmkTHU2riMVLcGnJWRHkHWZPnfbtuXcQVEwiBSjpJVRcCFG6LDbgTqt4s6BYxJqT5zriEaigzvFuj9V4s7QSJCs1Sj92tgDmE6YyTSR7UN9di2oHDCzk"
+
+	id, err = Parse(keyStrRSA)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if id.String() != keyStrRSA {
+		t.Errorf("string mismatch.\nwant: %q\ngot:  %q", keyStrRSA, id.String())
+	}
+}

example_test.go

@@ -9,7 +9,7 @@ import (
 )
 
 func ExampleWalkthrough() {
-	source, err := ucan.NewPrivKeyUCANSource(keyOne)
+	source, err := ucan.NewPrivKeySource(keyOne)
 	panicIfError(err)
 
 	subjectDID, err := ucan.DIDStringFromPublicKey(keyOne.GetPublic())

go.mod

@@ -7,7 +7,9 @@ require (
 	github.com/dgrijalva/jwt-go v3.2.0+incompatible
 	github.com/ipfs/go-cid v0.0.7
 	github.com/libp2p/go-libp2p-core v0.7.0
+	github.com/multiformats/go-multibase v0.0.3
 	github.com/multiformats/go-multihash v0.0.14
+	github.com/multiformats/go-varint v0.0.6
 	golang.org/x/crypto v0.0.0-20200622213623-75b288015ac9 // indirect
 	golang.org/x/sys v0.0.0-20200625212154-ddb9806d33ae // indirect
 )

token.go

@@ -99,7 +99,6 @@ type Fact struct {
 // func (fct *Fact) UnmarshalJSON(p []byte) error {
 // 	var str string
 // 	if json.Unmarshal(p, &str); err == nil {
-
 // 	}
 // }
 
@@ -110,20 +109,21 @@ type CIDBytesResolver interface {
 	ResolveCIDBytes(ctx context.Context, id cid.Cid) ([]byte, error)
 }
 
-// UCANSource creates tokens, and provides a verification key for all tokens
-// it creates
+// Source creates tokens, and provides a verification key for all tokens it
+// creates
 //
-// implementations of UCANSource must conform to the assertion test defined
-// in the spec subpackage
-type UCANSource interface {
+// implementations of Source must conform to the assertion test defined in the
+// spec subpackage
+type Source interface {
 	NewOriginUCAN(subjectDID string, att Attenuations, fct []Fact, notBefore, expires time.Time) (*UCAN, error)
 	NewAttenuatedUCAN(parent *UCAN, subjectDID string, att Attenuations, fct []Fact, notBefore, expires time.Time) (*UCAN, error)
 }
 
-type pkUCANSource struct {
+type pkSource struct {
 	pk            crypto.PrivKey
 	issuerDID     string
 	signingMethod jwt.SigningMethod
+
 	verifyKey *rsa.PublicKey
 	signKey   *rsa.PrivateKey
 
@@ -132,17 +132,19 @@ type pkUCANSource struct {
 	store    TokenStore
 }
 
-// assert pkUCANSource implements tokens at compile time
-var _ UCANSource = (*pkUCANSource)(nil)
+// assert pkSource implements tokens at compile time
+var _ Source = (*pkSource)(nil)
 
-// NewPrivKeyUCANSource creates an authentication interface backed by a single
+// NewPrivKeySource creates an authentication interface backed by a single
 // private key. Intended for a node running as remote, or providing a public API
-func NewPrivKeyUCANSource(privKey crypto.PrivKey) (UCANSource, error) {
+func NewPrivKeySource(privKey crypto.PrivKey) (Source, error) {
 	methodStr := ""
-	keyType := privKey.Type().String()
+	keyType := privKey.Type()
 	switch keyType {
-	case "RSA":
+	case crypto.RSA:
 		methodStr = "RS256"
+	case crypto.Ed25519:
+		methodStr = "EdDSA"
 	default:
 		return nil, fmt.Errorf("unsupported key type for token creation: %q", keyType)
 	}
@@ -176,7 +178,7 @@ func NewPrivKeyUCANSource(privKey crypto.PrivKey) (UCANSource, error) {
 		return nil, err
 	}
 
-	return &pkUCANSource{
+	return &pkSource{
 		pk:            privKey,
 		signingMethod: signingMethod,
 		verifyKey:     verifyKey,
@@ -185,11 +187,11 @@ func NewPrivKeyUCANSource(privKey crypto.PrivKey) (UCANSource, error) {
 	}, nil
 }
 
-func (a *pkUCANSource) NewOriginUCAN(subjectDID string, att Attenuations, fct []Fact, nbf, exp time.Time) (*UCAN, error) {
+func (a *pkSource) NewOriginUCAN(subjectDID string, att Attenuations, fct []Fact, nbf, exp time.Time) (*UCAN, error) {
 	return a.newUCAN(subjectDID, nil, att, fct, nbf, exp)
 }
 
-func (a *pkUCANSource) NewAttenuatedUCAN(parent *UCAN, subjectDID string, att Attenuations, fct []Fact, nbf, exp time.Time) (*UCAN, error) {
+func (a *pkSource) NewAttenuatedUCAN(parent *UCAN, subjectDID string, att Attenuations, fct []Fact, nbf, exp time.Time) (*UCAN, error) {
 	if !parent.Attenuations.Contains(att) {
 		return nil, fmt.Errorf("scope of ucan attenuations must be less than it's parent")
 	}
@@ -197,7 +199,7 @@ func (a *pkUCANSource) NewAttenuatedUCAN(parent *UCAN, subjectDID string, att At
 }
 
 // CreateToken returns a new JWT token
-func (a *pkUCANSource) newUCAN(subjectDID string, prf []Proof, att Attenuations, fct []Fact, nbf, exp time.Time) (*UCAN, error) {
+func (a *pkSource) newUCAN(subjectDID string, prf []Proof, att Attenuations, fct []Fact, nbf, exp time.Time) (*UCAN, error) {
 	// create a signer for rsa 256
 	t := jwt.New(a.signingMethod)
 

token_test.go

@@ -40,7 +40,7 @@ func init() {
 }
 
 func TestPrivKeySource(t *testing.T) {
-	source, err := ucan.NewPrivKeyUCANSource(keyOne)
+	source, err := ucan.NewPrivKeySource(keyOne)
 	if err != nil {
 		t.Fatal(err)
 	}