diff --git a/openpgp/keys.go b/openpgp/keys.go
index 216b812..a79a8c1 100644
--- a/openpgp/keys.go
+++ b/openpgp/keys.go
@@ -544,10 +544,10 @@ func NewEntity(name, comment, email string, config *packet.Config) (*Entity, err
 	return e, nil
 }
 
-// SerializePrivate serializes an Entity, including private key material, to
-// the given Writer. For now, it must only be used on an Entity returned from
-// NewEntity.
-// config is ignored
+// SerializePrivate serializes an Entity, including private key material, but
+// excluding signatures from other entities, to the given Writer.
+// Identities and subkeys are re-signed in case they changed since NewEntry.
+// If config is nil, sensible defaults will be used.
 func (e *Entity) SerializePrivate(w io.Writer, config *packet.Config) (err error) {
 	err = e.PrivateKey.Serialize(w)
 	if err != nil {
@@ -558,6 +558,10 @@ func (e *Entity) SerializePrivate(w io.Writer, config *packet.Config) (err error
 		if err != nil {
 			return
 		}
+		err = ident.SelfSignature.SignUserId(ident.UserId.Id, e.PrimaryKey, e.PrivateKey, config)
+		if err != nil {
+			return
+		}
 		err = ident.SelfSignature.Serialize(w)
 		if err != nil {
 			return
@@ -568,6 +572,10 @@ func (e *Entity) SerializePrivate(w io.Writer, config *packet.Config) (err error
 		if err != nil {
 			return
 		}
+		err = subkey.Sig.SignKey(subkey.PublicKey, e.PrivateKey, config)
+		if err != nil {
+			return
+		}
 		err = subkey.Sig.Serialize(w)
 		if err != nil {
 			return
@@ -576,8 +584,8 @@ func (e *Entity) SerializePrivate(w io.Writer, config *packet.Config) (err error
 	return nil
 }
 
-// Serialize writes the public part of the given Entity to w. (No private
-// key material will be output).
+// Serialize writes the public part of the given Entity to w, including
+// signatures from other entities. No private key material will be output.
 func (e *Entity) Serialize(w io.Writer) error {
 	err := e.PrimaryKey.Serialize(w)
 	if err != nil {