diff --git a/xwords4/relay/permid.cpp b/xwords4/relay/permid.cpp
index 77da4a96a..3c13bbb64 100644
--- a/xwords4/relay/permid.cpp
+++ b/xwords4/relay/permid.cpp
@@ -30,7 +30,7 @@ using namespace std;
 pthread_mutex_t PermID::s_guard = PTHREAD_MUTEX_INITIALIZER;
 string          PermID::s_serverName;
 int             PermID::s_nextId = 0;
-string          PermID::s_startTime;
+time_t          PermID::s_startTime;
 
 string
 PermID::GetNextUniqueID()
@@ -38,8 +38,8 @@ PermID::GetNextUniqueID()
     MutexLock ml( &s_guard );
 
     char buf[64];
-    snprintf( buf, sizeof(buf), "%s:%s:%d", s_serverName.c_str(), 
-              s_startTime.c_str(), ++s_nextId );
+    snprintf( buf, sizeof(buf), "%s:%x:%d", s_serverName.c_str(), 
+              (unsigned int)s_startTime, ++s_nextId );
     string s(buf);
 
     return s;
@@ -54,8 +54,6 @@ PermID::SetServerName( const char* name )
 /* static */ void
 PermID::SetStartTime( time_t startTime )
 {
-    char buf[16];
-    snprintf( buf, sizeof(buf), "%ld", startTime );
-    s_startTime = buf;
-    logf( XW_LOGINFO, "assigned startTime: %s", s_startTime.c_str() );
+    s_startTime = startTime;
+    logf( XW_LOGINFO, "assigned startTime: %ld", s_startTime );
 }
diff --git a/xwords4/relay/permid.h b/xwords4/relay/permid.h
index 43f73a572..8ea4ed2bd 100644
--- a/xwords4/relay/permid.h
+++ b/xwords4/relay/permid.h
@@ -45,7 +45,9 @@ class PermID {
                                                  unique to this relay
                                                  instance. */
     static int                s_nextId;       /* numeric part of ID */
-    static std::string        s_startTime;    /* allows multiple servers per 
-                                                 host to have uniquie names */
-}; 
+    static time_t             s_startTime;    /* allows multiple servers per
+                                                 host to have uniquie names
+                                                 and to ensure no duplications
+                                                 after a crash. */
+};
 #endif