diff --git a/Makefile b/Makefile
index becdf39..c1b9024 100644
--- a/Makefile
+++ b/Makefile
@@ -10,7 +10,7 @@ endif
 BINARY=keymaster
 
 # These are the values we want to pass for Version and BuildTime
-VERSION?=1.15.4
+VERSION?=1.15.5
 DEFAULT_HOST?=
 VERSION_FLAVOUR?=
 EXTRA_LDFLAGS?=
diff --git a/cmd/keymaster/main.go b/cmd/keymaster/main.go
index 8ed8620..4cf3673 100644
--- a/cmd/keymaster/main.go
+++ b/cmd/keymaster/main.go
@@ -299,19 +299,19 @@ func insertSSHCertIntoAgentORWriteToFilesystem(certText []byte,
 		return nil
 	}
 	logger.Debugf(1, "Non fatal, failed to insert into agent without expiration")
-	encodedSigner, err := x509.MarshalPKCS8PrivateKey(signer)
+	encodedSigner, err := ssh.MarshalPrivateKey(signer, "")
 	if err != nil {
 		return err
 	}
 	err = ioutil.WriteFile(
 		privateKeyPath,
-		pem.EncodeToMemory(&pem.Block{Type: "PRIVATE KEY", Bytes: encodedSigner}),
+		pem.EncodeToMemory(encodedSigner),
 		0600)
 	if err != nil {
 		return err
 	}
 	// now we need to write the certificate
-	sshCertPath := privateKeyPath + ".pub"
+	sshCertPath := privateKeyPath + "-cert.pub"
 	return ioutil.WriteFile(sshCertPath, certText, 0644)
 }
 
diff --git a/cmd/keymaster/main_test.go b/cmd/keymaster/main_test.go
index 81b1b90..535de72 100644
--- a/cmd/keymaster/main_test.go
+++ b/cmd/keymaster/main_test.go
@@ -6,12 +6,12 @@ import (
 	"crypto/rand"
 	"crypto/tls"
 	"crypto/x509"
-	"encoding/base64"
 	"encoding/json"
 	"fmt"
 	"io/ioutil"
 	"net/http"
 	"os"
+	"os/exec"
 	"path/filepath"
 	"runtime"
 	"testing"
@@ -20,6 +20,7 @@ import (
 	"golang.org/x/crypto/ssh"
 
 	"github.com/Cloud-Foundations/golib/pkg/log/testlogger"
+	"github.com/Cloud-Foundations/keymaster/lib/certgen"
 	"github.com/Cloud-Foundations/keymaster/lib/client/config"
 	"github.com/Cloud-Foundations/keymaster/lib/client/twofa/u2f"
 	"github.com/Cloud-Foundations/keymaster/lib/client/util"
@@ -202,41 +203,29 @@ func TestMost(t *testing.T) {
 
 }
 
-func goCertToFileString(c ssh.Certificate, username string) (string, error) {
-	certBytes := c.Marshal()
-	encoded := base64.StdEncoding.EncodeToString(certBytes)
-	fileComment := "/tmp/" + username + "-" + c.SignatureKey.Type() + "-cert.pub"
-	return c.Type() + " " + encoded + " " + fileComment, nil
-}
-
 func TestInsertSSHCertIntoAgentORWriteToFilesystem(t *testing.T) {
 	//step 1: generate
 	publicKey, privateKey, err := ed25519.GenerateKey(rand.Reader)
 	if err != nil {
 		t.Fatal(err)
 	}
+
 	sshPublic, err := ssh.NewPublicKey(publicKey)
 	if err != nil {
 		t.Fatal(err)
 	}
-	cert := ssh.Certificate{
-		Key:             sshPublic,
-		ValidPrincipals: []string{"username"},
-		ValidAfter:      uint64(time.Now().Unix()) - 10,
-		ValidBefore:     uint64(time.Now().Unix()) + 10,
-	}
+	sshPublicBytes := ssh.MarshalAuthorizedKey(sshPublic)
+
 	sshSigner, err := ssh.NewSignerFromKey(privateKey)
 	if err != nil {
 		t.Fatal(err)
 	}
-	err = cert.SignCert(rand.Reader, sshSigner)
-	if err != nil {
-		t.Fatal(err)
-	}
-	certString, err := goCertToFileString(cert, "username")
-	if err != nil {
-		t.Fatal(err)
-	}
+	seconds := 10
+	certDuration := time.Duration(seconds) * time.Second
+	extensions := make(map[string]string)
+
+	certString, _, err := certgen.GenSSHCertFileString("username", string(sshPublicBytes), sshSigner, "km.example.com", certDuration, extensions)
+
 	// This test needs a running agent... and remote windows
 	// builders do NOT have this... thus we need to abort this test
 	// until we have a way to NOT timeout on missing agent in
@@ -273,9 +262,23 @@ func TestInsertSSHCertIntoAgentORWriteToFilesystem(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	os.Remove(privateKeyPath)
-	// TODO: on linux/macos create agent + unix socket and pass that
+	defer os.Remove(privateKeyPath)
 
+	//t.Logf("certString='%s'", certString)
+
+	// TODO: on linux/macos create agent + unix socket and pass that
+	if oldSSHSock != "" && runtime.GOOS == "darwin" {
+		//reset the socket
+		err = os.Setenv("SSH_AUTH_SOCK", oldSSHSock)
+		if err != nil {
+			t.Fatal(err)
+		}
+		cmd := exec.Command("ssh-add", "-t", "30", privateKeyPath)
+		err := cmd.Run()
+		if err != nil {
+			t.Fatalf("Command finished with error: %v", err)
+		}
+	}
 }
 
 func TestMainSimple(t *testing.T) {