static byte[] userPermissionKey(UserPermission permission) {
    byte[] key = Bytes.toBytes(permission.getUser());
    byte[] qualifier = null;
    byte[] family = null;
    if (permission.getPermission().getAccessScope() == Permission.Scope.TABLE) {
      TablePermission tablePermission = (TablePermission) permission.getPermission();
      family = tablePermission.getFamily();
      qualifier = tablePermission.getQualifier();
    }

    if (family != null && family.length > 0) {
      key = Bytes.add(key, Bytes.add(new byte[] { ACL_KEY_DELIMITER }, family));
      if (qualifier != null && qualifier.length > 0) {
        key = Bytes.add(key, Bytes.add(new byte[] { ACL_KEY_DELIMITER }, qualifier));
      }
    }

    return key;
  }
Build qualifier key from user permission: username username,family username,family,qualifier
hbase-server/src/main/java/org/apache/hadoop/hbase/security/access/PermissionStorage.java