diff --git a/util/tests.py b/util/tests.py
index 194b1f7..f57aea1 100755
--- a/util/tests.py
+++ b/util/tests.py
@@ -22,6 +22,7 @@ def test_suite():
         doctest.DocFileSuite('defer.txt', optionflags=flags),
         doctest.DocFileSuite('property.txt', optionflags=flags),
         doctest.DocFileSuite('jeep.txt', optionflags=flags),
+        doctest.DocFileSuite('uid.txt', optionflags=flags),
         ))
 
 if __name__ == '__main__':
diff --git a/util/uid.py b/util/uid.py
new file mode 100644
index 0000000..c63b361
--- /dev/null
+++ b/util/uid.py
@@ -0,0 +1,52 @@
+#
+#  Copyright (c) 2007 Helmut Merz helmutm@cy55.de
+#
+#  This program is free software; you can redistribute it and/or modify
+#  it under the terms of the GNU General Public License as published by
+#  the Free Software Foundation; either version 2 of the License, or
+#  (at your option) any later version.
+#
+#  This program is distributed in the hope that it will be useful,
+#  but WITHOUT ANY WARRANTY; without even the implied warranty of
+#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#  GNU General Public License for more details.
+#
+#  You should have received a copy of the GNU General Public License
+#  along with this program; if not, write to the Free Software
+#  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+#
+
+"""
+Generate strange (not guessable) UIDs.
+
+$Id$
+"""
+
+import random
+
+
+bits = 128
+
+
+def generateUid(check=None, lowerCaseOnly=False, bits=bits, seed=None, base=62):
+    """ Generates a unique ID.
+    """
+    random.seed(seed)
+    OK = False
+    base = lowerCaseOnly and min(base, 36) or base
+    while not OK:
+        data = strBase(random.getrandbits(bits), base)
+        OK = check is None or check(data)
+    return data
+
+
+def strBase(n, base):
+    result = []
+    while n > 0:
+        n, r = divmod(n, base)
+        result.append(r)
+    return ''.join(reversed([toChar(n) for n in (result or [0])]))
+
+def toChar(n):
+    return n < 10 and chr(48+n) or n < 36 and chr(87+n) or chr(29+n)
+
diff --git a/util/uid.txt b/util/uid.txt
new file mode 100644
index 0000000..8e90e47
--- /dev/null
+++ b/util/uid.txt
@@ -0,0 +1,26 @@
+===========================
+Generate Unique Identifiers
+===========================
+
+$Id$
+
+  >>> from cybertools.util.uid import generateUid
+
+  >>> generateUid(seed=42)
+  '5MdsLTYmogAeWfbrLDBY8l'
+
+  >>> generateUid(seed=42)
+  '5MdsLTYmogAeWfbrLDBY8l'
+
+  >>> def checkIt(id):
+  ...     return id != '5MdsLTYmogAeWfbrLDBY8l'
+
+  >>> generateUid(check=checkIt, seed=42)
+  '15pahuNd5rxoekvZSMGAl1'
+
+  >>> generateUid(lowerCaseOnly=True, seed=42)
+  'b8lhps8li07acdu7i0w01b0rh'
+
+  >>> generateUid()
+  '...'
+