1 files changed, 44 insertions, 5 deletions
diff --git a/satp/crypto-kd.go b/satp/crypto-kd.go
index db52f77..73d2faa 100644
--- a/satp/crypto-kd.go
+++ b/satp/crypto-kd.go
@@ -30,6 +30,11 @@
 
 package satp
 
+import (
+	"errors"
+	"strings"
+)
+
 type KDRole int
 type KeyUsage int
 type Label uint32
@@ -38,11 +43,6 @@ const (
 	RoleLeft KDRole = iota
 	RoleRight
 
-	RoleServer = RoleLeft
-	RoleClient = RoleRight
-	RoleAlice  = RoleLeft
-	RoleBob    = RoleRight
-
 	UsageEncryptKey KeyUsage = iota
 	UsageEncryptSalt
 	UsageAuthKey
@@ -55,6 +55,45 @@ const (
 	LabelRightAuthKey     = 0xC1DFD96E
 )
 
+func (r KDRole) String() string {
+	switch r {
+	case RoleLeft:
+		return "left"
+	case RoleRight:
+		return "right"
+	}
+	return "unknown"
+}
+
+func (r *KDRole) FromString(str string) (err error) {
+	switch strings.ToLower(str) {
+	case "server":
+		fallthrough
+	case "alice":
+		fallthrough
+	case "left":
+		*r = RoleLeft
+	case "client":
+		fallthrough
+	case "bob":
+		fallthrough
+	case "right":
+		*r = RoleRight
+	default:
+		return errors.New("invalid role: '" + str + "'")
+	}
+	return
+}
+
+func (r KDRole) MarshalText() (data []byte, err error) {
+	data = []byte(r.String())
+	return
+}
+
+func (r *KDRole) UnmarshalText(data []byte) (err error) {
+	return r.FromString(string(data))
+}
+
 type KeyDerivation interface {
 	Generate(dir Direction, usage KeyUsage, sequenceNumber uint32, out []byte) error
 }