diff --git a/cluster/cluster.go b/cluster/cluster.go
index 548345d0..085703de 100644
--- a/cluster/cluster.go
+++ b/cluster/cluster.go
@@ -1007,6 +1007,10 @@ func (c *cluster) AddIdentity(origin string, identity iamidentity.User) error {
 		return ErrDegraded
 	}
 
+	if err := identity.Validate(); err != nil {
+		return fmt.Errorf("invalid identity: %w", err)
+	}
+
 	if !c.IsRaftLeader() {
 		return c.forwarder.AddIdentity(origin, identity)
 	}
diff --git a/encoding/token/token.go b/encoding/token/token.go
new file mode 100644
index 00000000..45c2b175
--- /dev/null
+++ b/encoding/token/token.go
@@ -0,0 +1,45 @@
+package token
+
+import "strings"
+
+func Marshal(username, token string) string {
+	username = strings.ReplaceAll(username, ":", "::")
+
+	return username + ":" + token
+}
+
+// Unmarshal splits a username/token combination into a username and
+// token. If the input doesn't contain a username, the whole input
+// is returned as token.
+func Unmarshal(usertoken string) (string, string) {
+	r := []rune(usertoken)
+
+	count := 0
+	index := -1
+	for i, ru := range r {
+		if ru == ':' {
+			count++
+			continue
+		}
+
+		if count > 0 && count%2 != 0 {
+			index = i - 1
+			break
+		}
+
+		count = 0
+	}
+
+	if index == -1 {
+		return "", usertoken
+	}
+
+	before, after := r[:index], r[index+1:]
+
+	username := string(before)
+	token := string(after)
+
+	username = strings.ReplaceAll(username, "::", ":")
+
+	return username, token
+}
diff --git a/encoding/token/token_test.go b/encoding/token/token_test.go
new file mode 100644
index 00000000..ad0df144
--- /dev/null
+++ b/encoding/token/token_test.go
@@ -0,0 +1,41 @@
+package token
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestMarshal(t *testing.T) {
+	token := "xxx"
+
+	data := [][2]string{
+		{"", ""},
+		{"foo", "foo"},
+		{"foo:bar", "foo::bar"},
+		{"foo::bar", "foo::::bar"},
+	}
+
+	for _, d := range data {
+		encoded := Marshal(d[0], token)
+		require.Equal(t, d[1]+":"+token, encoded, d[1])
+	}
+}
+
+func TestUnmarshal(t *testing.T) {
+	data := [][3]string{
+		{"foo", "", "foo"},
+		{"fo::o", "", "fo::o"},
+		{"::foo", "", "::foo"},
+		{":xxx", "", "xxx"},
+		{"foo:xxx", "foo", "xxx"},
+		{"foo::bar:xxx", "foo:bar", "xxx"},
+		{"foo::::bar:xxx", "foo::bar", "xxx"},
+	}
+
+	for _, d := range data {
+		username, token := Unmarshal(d[0])
+		require.Equal(t, d[1], username, d[0])
+		require.Equal(t, d[2], token)
+	}
+}
diff --git a/http/handler/api/cluster.go b/http/handler/api/cluster.go
index cc8fb139..afbe1be4 100644
--- a/http/handler/api/cluster.go
+++ b/http/handler/api/cluster.go
@@ -744,7 +744,7 @@ func (h *ClusterHandler) DeleteProcess(c echo.Context) error {
 func (h *ClusterHandler) AddIdentity(c echo.Context) error {
 	ctxuser := util.DefaultContext(c, "user", "")
 	superuser := util.DefaultContext(c, "superuser", false)
-	domain := util.DefaultQuery(c, "domain", "$none")
+	domain := util.DefaultQuery(c, "domain", "")
 
 	user := api.IAMUser{}
 
@@ -799,7 +799,7 @@ func (h *ClusterHandler) AddIdentity(c echo.Context) error {
 func (h *ClusterHandler) UpdateIdentity(c echo.Context) error {
 	ctxuser := util.DefaultContext(c, "user", "")
 	superuser := util.DefaultContext(c, "superuser", false)
-	domain := util.DefaultQuery(c, "domain", "$none")
+	domain := util.DefaultQuery(c, "domain", "")
 	name := util.PathParam(c, "name")
 
 	if !h.iam.Enforce(ctxuser, domain, "iam:"+name, "write") {
@@ -880,7 +880,7 @@ func (h *ClusterHandler) UpdateIdentity(c echo.Context) error {
 func (h *ClusterHandler) UpdateIdentityPolicies(c echo.Context) error {
 	ctxuser := util.DefaultContext(c, "user", "")
 	superuser := util.DefaultContext(c, "superuser", false)
-	domain := util.DefaultQuery(c, "domain", "$none")
+	domain := util.DefaultQuery(c, "domain", "")
 	name := util.PathParam(c, "name")
 
 	if !h.iam.Enforce(ctxuser, domain, "iam:"+name, "write") {
@@ -952,7 +952,7 @@ func (h *ClusterHandler) UpdateIdentityPolicies(c echo.Context) error {
 // @Router /api/v3/cluster/db/user [get]
 func (h *ClusterHandler) ListStoreIdentities(c echo.Context) error {
 	ctxuser := util.DefaultContext(c, "user", "")
-	domain := util.DefaultQuery(c, "domain", "$none")
+	domain := util.DefaultQuery(c, "domain", "")
 
 	updatedAt, identities := h.cluster.ListIdentities()
 
@@ -991,7 +991,7 @@ func (h *ClusterHandler) ListStoreIdentities(c echo.Context) error {
 // @Router /api/v3/cluster/db/user/{name} [get]
 func (h *ClusterHandler) ListStoreIdentity(c echo.Context) error {
 	ctxuser := util.DefaultContext(c, "user", "")
-	domain := util.DefaultQuery(c, "domain", "$none")
+	domain := util.DefaultQuery(c, "domain", "")
 	name := util.PathParam(c, "name")
 
 	if !h.iam.Enforce(ctxuser, domain, "iam:"+name, "read") {
@@ -1069,7 +1069,7 @@ func (h *ClusterHandler) ReloadIAM(c echo.Context) error {
 // @Router /api/v3/cluster/iam/user [get]
 func (h *ClusterHandler) ListIdentities(c echo.Context) error {
 	ctxuser := util.DefaultContext(c, "user", "")
-	domain := util.DefaultQuery(c, "domain", "$none")
+	domain := util.DefaultQuery(c, "domain", "")
 
 	identities := h.iam.ListIdentities()
 
@@ -1115,7 +1115,7 @@ func (h *ClusterHandler) ListIdentities(c echo.Context) error {
 // @Router /api/v3/cluster/iam/user/{name} [get]
 func (h *ClusterHandler) ListIdentity(c echo.Context) error {
 	ctxuser := util.DefaultContext(c, "user", "")
-	domain := util.DefaultQuery(c, "domain", "$none")
+	domain := util.DefaultQuery(c, "domain", "")
 	name := util.PathParam(c, "name")
 
 	if !h.iam.Enforce(ctxuser, domain, "iam:"+name, "read") {
diff --git a/iam/identity/identity.go b/iam/identity/identity.go
index 57ba5710..8453b774 100644
--- a/iam/identity/identity.go
+++ b/iam/identity/identity.go
@@ -2,10 +2,11 @@ package identity
 
 import (
 	"fmt"
-	"regexp"
+	"strings"
 	"sync"
 	"time"
 
+	enctoken "github.com/datarhei/core/v16/encoding/token"
 	"github.com/datarhei/core/v16/iam/jwks"
 	"github.com/datarhei/core/v16/log"
 	"github.com/google/uuid"
@@ -45,16 +46,13 @@ type UserAuthServices struct {
 	Session []string `json:"session"` // Secrets for session JWT
 }
 
-func (u *User) validate() error {
+func (u *User) Validate() error {
 	if len(u.Name) == 0 {
 		return fmt.Errorf("a name is required")
 	}
 
-	chars := `A-Za-z0-9._-`
-
-	re := regexp.MustCompile(`[^` + chars + `]`)
-	if re.MatchString(u.Name) {
-		return fmt.Errorf("the name can only contain [%s]", chars)
+	if strings.HasPrefix(u.Name, "$") {
+		return fmt.Errorf("name is not allowed to start with $")
 	}
 
 	if len(u.Auth.API.Auth0.User) != 0 {
@@ -363,7 +361,7 @@ func (i *identity) GetServiceToken() string {
 			continue
 		}
 
-		return i.Name() + ":" + token
+		return enctoken.Marshal(i.Name(), token)
 	}
 
 	return ""
@@ -608,7 +606,7 @@ func (im *identityManager) Reload() error {
 			continue
 		}
 
-		if err := u.validate(); err != nil {
+		if err := u.Validate(); err != nil {
 			continue
 		}
 
@@ -624,7 +622,7 @@ func (im *identityManager) Reload() error {
 }
 
 func (im *identityManager) Create(u User) error {
-	if err := u.validate(); err != nil {
+	if err := u.Validate(); err != nil {
 		return err
 	}
 
@@ -689,7 +687,7 @@ func (im *identityManager) create(u User) (*identity, error) {
 }
 
 func (im *identityManager) Update(name string, u User) error {
-	if err := u.validate(); err != nil {
+	if err := u.Validate(); err != nil {
 		return err
 	}
 
diff --git a/iam/identity/identity_test.go b/iam/identity/identity_test.go
index 87c3e724..c864969a 100644
--- a/iam/identity/identity_test.go
+++ b/iam/identity/identity_test.go
@@ -19,15 +19,19 @@ func createAdapter() (Adapter, error) {
 func TestUserName(t *testing.T) {
 	user := User{}
 
-	err := user.validate()
+	err := user.Validate()
 	require.Error(t, err)
 
 	user.Name = "foobar_5"
-	err = user.validate()
+	err = user.Validate()
+	require.NoError(t, err)
+
+	user.Name = "foobar:5"
+	err = user.Validate()
 	require.NoError(t, err)
 
 	user.Name = "$foob:ar"
-	err = user.validate()
+	err = user.Validate()
 	require.Error(t, err)
 }
 
diff --git a/rtmp/rtmp.go b/rtmp/rtmp.go
index be349b16..b5cf16ae 100644
--- a/rtmp/rtmp.go
+++ b/rtmp/rtmp.go
@@ -12,6 +12,7 @@ import (
 	"time"
 
 	"github.com/datarhei/core/v16/cluster/proxy"
+	enctoken "github.com/datarhei/core/v16/encoding/token"
 	"github.com/datarhei/core/v16/iam"
 	iamidentity "github.com/datarhei/core/v16/iam/identity"
 	"github.com/datarhei/core/v16/log"
@@ -212,7 +213,7 @@ func (s *server) log(who, handler, action, resource, message string, client net.
 func GetToken(u *url.URL) (string, string) {
 	q := u.Query()
 	if q.Has("token") {
-		// The token was in the query. Return the unmomdified path and the token
+		// The token was in the query. Return the unmomdified path and the token.
 		return u.Path, q.Get("token")
 	}
 
@@ -471,18 +472,16 @@ func (s *server) findIdentityFromStreamKey(key string) (string, error) {
 		return "$anon", nil
 	}
 
-	var identity iamidentity.Verifier
-	var err error
+	var identity iamidentity.Verifier = nil
+	var err error = nil
 
 	var token string
 
-	before, after, found := strings.Cut(key, ":")
-	if !found {
+	username, token := enctoken.Unmarshal(key)
+	if len(username) == 0 {
 		identity = s.iam.GetDefaultVerifier()
-		token = before
 	} else {
-		identity, err = s.iam.GetVerifier(before)
-		token = after
+		identity, err = s.iam.GetVerifier(username)
 	}
 
 	if err != nil {
diff --git a/srt/srt.go b/srt/srt.go
index 443bbf77..d39ba1d6 100644
--- a/srt/srt.go
+++ b/srt/srt.go
@@ -10,6 +10,7 @@ import (
 	"time"
 
 	"github.com/datarhei/core/v16/cluster/proxy"
+	enctoken "github.com/datarhei/core/v16/encoding/token"
 	"github.com/datarhei/core/v16/iam"
 	iamidentity "github.com/datarhei/core/v16/iam/identity"
 	"github.com/datarhei/core/v16/log"
@@ -493,15 +494,11 @@ func (s *server) findIdentityFromToken(key string) (string, error) {
 	var identity iamidentity.Verifier
 	var err error
 
-	var token string
-
-	before, after, found := strings.Cut(key, ":")
-	if !found {
+	username, token := enctoken.Unmarshal(key)
+	if len(username) == 0 {
 		identity = s.iam.GetDefaultVerifier()
-		token = before
 	} else {
-		identity, err = s.iam.GetVerifier(before)
-		token = after
+		identity, err = s.iam.GetVerifier(username)
 	}
 
 	if err != nil {