split ErrInvalidKey into ErrInvalidType and ErrInvalidKey

ecdsa.go

@@ -69,7 +69,7 @@ func (m *SigningMethodECDSA) Verify(signingString, signature string, key interfa
 	case *ecdsa.PublicKey:
 		ecdsaKey = k
 	default:
-		return ErrInvalidKey
+		return ErrInvalidType
 	}
 
 	if len(sig) != 2*m.KeySize {
@@ -103,7 +103,7 @@ func (m *SigningMethodECDSA) Sign(signingString string, key interface{}) (string
 	case *ecdsa.PrivateKey:
 		ecdsaKey = k
 	default:
-		return "", ErrInvalidKey
+		return "", ErrInvalidType
 	}
 
 	// Create the hasher

errors.go

@@ -6,7 +6,8 @@ import (
 
 // Error constants
 var (
-	ErrInvalidKey       = errors.New("key is invalid or of invalid type")
+	ErrInvalidKey       = errors.New("key is invalid")
+	ErrInvalidType      = errors.New("key is of invalid type")
 	ErrHashUnavailable  = errors.New("the requested hash function is unavailable")
 	ErrNoTokenInRequest = errors.New("no token present in request")
 )

hmac.go

@@ -49,7 +49,7 @@ func (m *SigningMethodHMAC) Verify(signingString, signature string, key interfac
 	// Verify the key is the right type
 	keyBytes, ok := key.([]byte)
 	if !ok {
-		return ErrInvalidKey
+		return ErrInvalidType
 	}
 
 	// Decode signature, for comparison

rsa.go

@@ -65,7 +65,7 @@ func (m *SigningMethodRSA) Verify(signingString, signature string, key interface
 	case *rsa.PublicKey:
 		rsaKey = k
 	default:
-		return ErrInvalidKey
+		return ErrInvalidType
 	}
 
 	// Create hasher

rsa_pss.go

@@ -106,7 +106,7 @@ func (m *SigningMethodRSAPSS) Sign(signingString string, key interface{}) (strin
 	case *rsa.PrivateKey:
 		rsaKey = k
 	default:
-		return "", ErrInvalidKey
+		return "", ErrInvalidType
 	}
 
 	// Create the hasher