Migrate to Go modules

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <alexellis2@gmail.com>

gateway/vendor/github.com/nats-io/nkeys/strkey.go

@@ -17,7 +17,6 @@ import (
 	"bytes"
 	"encoding/base32"
 	"encoding/binary"
-
 	"golang.org/x/crypto/ed25519"
 )
 
@@ -47,7 +46,7 @@ const (
 	PrefixByteUser PrefixByte = 20 << 3 // Base32-encodes to 'U...'
 
 	// PrefixByteUnknown is for unknown prefixes.
-	PrefixByteUknown PrefixByte = 23 << 3 // Base32-encodes to 'X...'
+	PrefixByteUnknown PrefixByte = 23 << 3 // Base32-encodes to 'X...'
 )
 
 // Set our encoding to not include padding '=='
@@ -188,10 +187,11 @@ func DecodeSeed(src []byte) (PrefixByte, []byte, error) {
 	return PrefixByte(b2), raw[2:], nil
 }
 
+// Prefix returns PrefixBytes of its input
 func Prefix(src string) PrefixByte {
 	b, err := decode([]byte(src))
 	if err != nil {
-		return PrefixByteUknown
+		return PrefixByteUnknown
 	}
 	prefix := PrefixByte(b[0])
 	err = checkValidPrefixByte(prefix)
@@ -203,7 +203,7 @@ func Prefix(src string) PrefixByte {
 	if PrefixByte(b1) == PrefixByteSeed {
 		return PrefixByteSeed
 	}
-	return PrefixByteUknown
+	return PrefixByteUnknown
 }
 
 // IsValidPublicKey will decode and verify that the string is a valid encoded public key.
@@ -288,3 +288,19 @@ func (p PrefixByte) String() string {
 	}
 	return "unknown"
 }
+
+// CompatibleKeyPair returns an error if the KeyPair doesn't match expected PrefixByte(s)
+func CompatibleKeyPair(kp KeyPair, expected ...PrefixByte) error {
+	pk, err := kp.PublicKey()
+	if err != nil {
+		return err
+	}
+	pkType := Prefix(pk)
+	for _, k := range expected {
+		if pkType == k {
+			return nil
+		}
+	}
+
+	return ErrIncompatibleKey
+}