add functions for converting libp2p keys to stdlib variants (#125)

crypto/ecdsa.go

@@ -37,6 +37,8 @@ var (
 	ErrNilSig = errors.New("sig is nil")
 	// ErrNilPrivateKey is returned when a nil private key is provided
 	ErrNilPrivateKey = errors.New("private key is nil")
+	// ErrNilPublicKey is returned when a nil public key is provided
+	ErrNilPublicKey = errors.New("public key is nil")
 	// ECDSACurve is the default ecdsa curve used
 	ECDSACurve = elliptic.P256()
 )

crypto/key_not_openssl.go

@@ -38,3 +38,43 @@ func KeyPairFromStdKey(priv crypto.PrivateKey) (PrivKey, PubKey, error) {
 		return nil, nil, ErrBadKeyType
 	}
 }
+
+// PrivKeyToStdKey converts libp2p/go-libp2p-core/crypto private keys to standard library (and secp256k1) private keys
+func PrivKeyToStdKey(priv PrivKey) (crypto.PrivateKey, error) {
+	if priv == nil {
+		return nil, ErrNilPrivateKey
+	}
+
+	switch p := priv.(type) {
+	case *RsaPrivateKey:
+		return &p.sk, nil
+	case *ECDSAPrivateKey:
+		return p.priv, nil
+	case *Ed25519PrivateKey:
+		return &p.k, nil
+	case *Secp256k1PrivateKey:
+		return p, nil
+	default:
+		return nil, ErrBadKeyType
+	}
+}
+
+// PubKeyToStdKey converts libp2p/go-libp2p-core/crypto private keys to standard library (and secp256k1) public keys
+func PubKeyToStdKey(pub PubKey) (crypto.PublicKey, error) {
+	if pub == nil {
+		return nil, ErrNilPublicKey
+	}
+
+	switch p := pub.(type) {
+	case *RsaPublicKey:
+		return &p.k, nil
+	case *ECDSAPublicKey:
+		return p.pub, nil
+	case *Ed25519PublicKey:
+		return p.k, nil
+	case *Secp256k1PublicKey:
+		return p, nil
+	default:
+		return nil, ErrBadKeyType
+	}
+}

crypto/key_openssl.go

@@ -45,3 +45,50 @@ func KeyPairFromStdKey(priv crypto.PrivateKey) (PrivKey, PubKey, error) {
 		return nil, nil, ErrBadKeyType
 	}
 }
+
+// PrivKeyToStdKey converts libp2p/go-libp2p-core/crypto private keys to standard library (and secp256k1) private keys
+func PrivKeyToStdKey(priv PrivKey) (crypto.PrivateKey, error) {
+	if priv == nil {
+		return nil, ErrNilPrivateKey
+	}
+	switch p := priv.(type) {
+	case *opensslPrivateKey:
+		raw, err := p.Raw()
+		if err != nil {
+			return nil, err
+		}
+		return x509.ParsePKCS1PrivateKey(raw)
+	case *ECDSAPrivateKey:
+		return p.priv, nil
+	case *Ed25519PrivateKey:
+		return &p.k, nil
+	case *Secp256k1PrivateKey:
+		return p, nil
+	default:
+		return nil, ErrBadKeyType
+	}
+}
+
+// PubKeyToStdKey converts libp2p/go-libp2p-core/crypto private keys to standard library (and secp256k1) public keys
+func PubKeyToStdKey(pub PubKey) (crypto.PublicKey, error) {
+	if pub == nil {
+		return nil, ErrNilPublicKey
+	}
+
+	switch p := pub.(type) {
+	case *opensslPublicKey:
+		raw, err := p.Raw()
+		if err != nil {
+			return nil, err
+		}
+		return x509.ParsePKIXPublicKey(raw)
+	case *ECDSAPublicKey:
+		return p.pub, nil
+	case *Ed25519PublicKey:
+		return p.k, nil
+	case *Secp256k1PublicKey:
+		return p, nil
+	default:
+		return nil, ErrBadKeyType
+	}
+}

crypto/key_test.go

@@ -8,7 +8,9 @@ import (
 	"crypto/elliptic"
 	"crypto/rand"
 	"crypto/rsa"
+	"crypto/x509"
 	"fmt"
+	"reflect"
 	"testing"
 
 	btcec "github.com/btcsuite/btcd/btcec"
@@ -111,6 +113,65 @@ func TestKeyPairFromKey(t *testing.T) {
 			if !v {
 				t.Error("signature was not verified")
 			}
+
+			stdPub, err := PubKeyToStdKey(pub)
+			if stdPub == nil {
+				t.Errorf("err getting std public key from key: %v", err)
+			}
+
+			var stdPubBytes []byte
+
+			switch p := stdPub.(type) {
+			case *Secp256k1PublicKey:
+				stdPubBytes, err = p.Raw()
+			case ed25519.PublicKey:
+				stdPubBytes = []byte(p)
+			default:
+				stdPubBytes, err = x509.MarshalPKIXPublicKey(stdPub)
+			}
+
+			if err != nil {
+				t.Errorf("Error while marshaling %v key: %v", reflect.TypeOf(stdPub), err)
+			}
+
+			pubBytes, err := pub.Raw()
+			if err != nil {
+				t.Errorf("err getting raw bytes for %v key: %v", reflect.TypeOf(pub), err)
+			}
+			if !bytes.Equal(stdPubBytes, pubBytes) {
+				t.Errorf("err roundtripping %v key", reflect.TypeOf(pub))
+			}
+
+			stdPriv, err := PrivKeyToStdKey(priv)
+			if stdPub == nil {
+				t.Errorf("err getting std private key from key: %v", err)
+			}
+
+			var stdPrivBytes []byte
+
+			switch p := stdPriv.(type) {
+			case *Secp256k1PrivateKey:
+				stdPrivBytes, err = p.Raw()
+			case *ecdsa.PrivateKey:
+				stdPrivBytes, err = x509.MarshalECPrivateKey(p)
+			case *ed25519.PrivateKey:
+				stdPrivBytes = *p
+			case *rsa.PrivateKey:
+				stdPrivBytes = x509.MarshalPKCS1PrivateKey(p)
+			}
+
+			if err != nil {
+				t.Errorf("err marshaling %v key: %v", reflect.TypeOf(stdPriv), err)
+			}
+
+			privBytes, err := priv.Raw()
+			if err != nil {
+				t.Errorf("err getting raw bytes for %v key: %v", reflect.TypeOf(priv), err)
+			}
+
+			if !bytes.Equal(stdPrivBytes, privBytes) {
+				t.Errorf("err roundtripping %v key", reflect.TypeOf(priv))
+			}
 		})
 	}
 }