diff --git a/security/principal.go b/security/principal.go
index 8f4906c..f0dba02 100644
--- a/security/principal.go
+++ b/security/principal.go
@@ -76,17 +76,6 @@
 	return newPersistentPrincipalFromSigner(security.NewInMemoryECDSASigner(key), dir)
 }
 
-// CreateOrOverwritePersistentPrincipal behaves like CreatePersistentPrincipal except that
-// if the provided directory holds any preexisting principal data then the data gets
-// overwritten.  Any prexising private key, BlessingRoots and BlessingStore would get lost
-// as a result of calling this function.
-func CreateOrOverwritePersistentPrincipal(dir string, passphrase []byte) (principal security.Principal, err error) {
-	if err := removePersistentPrincipal(dir); err != nil {
-		return nil, err
-	}
-	return CreatePersistentPrincipal(dir, passphrase)
-}
-
 // InitDefaultBlessings uses the provided principal to create a self blessing for name 'name',
 // sets it as default on the principal's BlessingStore and adds it as root to the principal's BlessingRoots.
 func InitDefaultBlessings(p security.Principal, name string) error {
@@ -106,16 +95,6 @@
 	return nil
 }
 
-func removePersistentPrincipal(dir string) error {
-	files := []string{privateKeyFile, blessingRootsDataFile, blessingRootsSigFile, blessingStoreDataFile, blessingStoreSigFile}
-	for _, f := range files {
-		if err := os.Remove(path.Join(dir, f)); err != nil && !os.IsNotExist(err) {
-			return err
-		}
-	}
-	return nil
-}
-
 func newPersistentPrincipalFromSigner(signer security.Signer, dir string) (security.Principal, error) {
 	serializationSigner, err := security.CreatePrincipal(signer, nil, nil)
 	if err != nil {
diff --git a/security/principal_test.go b/security/principal_test.go
index b717f92..06de1ea 100644
--- a/security/principal_test.go
+++ b/security/principal_test.go
@@ -66,14 +66,10 @@
 	if err != nil {
 		t.Fatal(err)
 	}
-	p, err = CreatePersistentPrincipal(dir, passphrase)
+	_, err = CreatePersistentPrincipal(dir, passphrase)
 	if err == nil {
 		t.Error("CreatePersistentPrincipal passed unexpectedly")
 	}
-	p, err = CreateOrOverwritePersistentPrincipal(dir, passphrase)
-	if err != nil {
-		t.Errorf("CreateOrOverwritePersistentPrincipal failed unexpectedly: %v", err)
-	}
 
 	sig, err := p.Sign(message)
 	if err != nil {
diff --git a/security/serializer_reader_writer.go b/security/serializer_reader_writer.go
new file mode 100644
index 0000000..55248e4
--- /dev/null
+++ b/security/serializer_reader_writer.go
@@ -0,0 +1,16 @@
+package security
+
+import (
+	"io"
+)
+
+// SerializerReaderWriter is a factory for managing the readers and writers used for
+// serialization and deserialization of signed data.
+type SerializerReaderWriter interface {
+	// Readers returns io.ReadCloser for reading serialized data and its
+	// integrity signature.
+	Readers() (data io.ReadCloser, signature io.ReadCloser, err error)
+	// Writers returns io.WriteCloser for writing serialized data and its
+	// integrity signature.
+	Writers() (data io.WriteCloser, signature io.WriteCloser, err error)
+}
diff --git a/tools/principal/main.go b/tools/principal/main.go
index f865365..c05eb12 100644
--- a/tools/principal/main.go
+++ b/tools/principal/main.go
@@ -344,8 +344,8 @@
 environment variables for other veyron applications.
 
 The operation fails if the directory already contains a principal. In this case
-the --overwrite flag can be provided to overwrite the existing principal data in
-the directory.
+the --overwrite flag can be provided to clear the directory and write out a
+new principal.
 `,
 		ArgsName: "<directory> <blessing>",
 		ArgsLong: `
@@ -363,7 +363,10 @@
 				err error
 			)
 			if flagCreateOverwrite {
-				p, err = vsecurity.CreateOrOverwritePersistentPrincipal(dir, nil)
+				if err = os.RemoveAll(dir); err != nil {
+					return err
+				}
+				p, err = vsecurity.CreatePersistentPrincipal(dir, nil)
 			} else {
 				p, err = vsecurity.CreatePersistentPrincipal(dir, nil)
 			}