diff --git a/internal/handler/msgpack.go b/internal/handler/msgpack.go
index 64def3a..ffc460b 100644
--- a/internal/handler/msgpack.go
+++ b/internal/handler/msgpack.go
@@ -279,6 +279,13 @@ func (m *MsgPackHandler) parseCommand(frame []byte, command *protocol.Command) e
 		}
 
 		command.Command = revokeCertificateCommand
+	case messages.CmdSignOpenPGP:
+		signOpenPGPCommand, err := m.parseSignOpenPGPCommand(frame)
+		if err != nil {
+			return err
+		}
+
+		command.Command = signOpenPGPCommand
 	default:
 		return fmt.Errorf("unhandled command code %s", command.Announce.Code)
 	}
@@ -401,6 +408,18 @@ func (m *MsgPackHandler) parseRevokeCertificateCommand(frame []byte) (*messages.
 	return &command, nil
 }
 
+func (m *MsgPackHandler) parseSignOpenPGPCommand(frame []byte) (*messages.SignOpenPGPCommand, error) {
+	var command messages.SignOpenPGPCommand
+
+	if err := msgpack.Unmarshal(frame, &command); err != nil {
+		m.logger.WithError(err).Errorf("unmarshal failed")
+
+		return nil, errors.New("could not unmarshal sign OpenPGP command")
+	}
+
+	return &command, nil
+}
+
 func New(logger *logrus.Logger, handlers ...RegisterHandler) (protocol.ServerHandler, error) {
 	messages.RegisterGeneratedResolver()
 
diff --git a/pkg/messages/messages.go b/pkg/messages/messages.go
index bdf5077..3403a75 100644
--- a/pkg/messages/messages.go
+++ b/pkg/messages/messages.go
@@ -394,3 +394,37 @@ func (r *RevokeCertificateResponse) String() string {
 		r.IssuerID, new(big.Int).SetBytes(r.Serial).Text(16), r.RevokedAt.Format(time.RFC3339),
 	)
 }
+
+type SignOpenPGPCommand struct {
+	IssuerID       string   `msgpack:"issuer_id"`
+	ProfileName    string   `msgpack:"profile_name"`
+	PublicKey      []byte   `msgpack:"public_key"`
+	CommonName     string   `msgpack:"cn"`
+	EmailAddresses []string `msgpack:"email_addresses"`
+}
+
+func (c *SignOpenPGPCommand) String() string {
+	builder := &strings.Builder{}
+
+	_, _ = fmt.Fprintf(
+		builder, "issuer_id=%s, profile_name=%s, cn=%s", c.IssuerID, c.ProfileName, c.CommonName,
+	)
+
+	if len(c.EmailAddresses) > 0 {
+		builder.WriteString(", email_addresses=[")
+
+		builder.WriteString(strings.Join(c.EmailAddresses, ", "))
+
+		builder.WriteRune(']')
+	}
+
+	return builder.String()
+}
+
+type SignOpenPGPResponse struct {
+	SignatureData []byte `msgpack:"signature_data"`
+}
+
+func (r *SignOpenPGPResponse) String() string {
+	return fmt.Sprintf("sig_data of %d bytes", len(r.SignatureData))
+}