diff --git a/app/models/attachment.rb b/app/models/attachment.rb
index 08f440816e17d126a6c5543b1050b99b25f57d99..f44fe8b4d35ae6cdff34760c66d28dcb8fb53de8 100644
--- a/app/models/attachment.rb
+++ b/app/models/attachment.rb
@@ -40,7 +40,7 @@ class Attachment < ActiveRecord::Base
       @temp_file = incoming_file
       if @temp_file.size > 0
         self.filename = sanitize_filename(@temp_file.original_filename)
-        self.disk_filename = DateTime.now.strftime("%y%m%d%H%M%S") + "_" + self.filename
+        self.disk_filename = Attachment.disk_filename(filename)
         self.content_type = @temp_file.content_type.to_s.chomp
         self.filesize = @temp_file.size
       end
@@ -100,4 +100,17 @@ private
     # Finally, replace all non alphanumeric, hyphens or periods with underscore
     @filename = just_filename.gsub(/[^\w\.\-]/,'_') 
   end
+  
+  # Returns an ASCII or hashed filename
+  def self.disk_filename(filename)
+    df = DateTime.now.strftime("%y%m%d%H%M%S") + "_"
+    if filename =~ %r{^[a-zA-Z0-9_\.\-]*$}
+      df << filename
+    else
+      df << Digest::MD5.hexdigest(filename)
+      # keep the extension if any
+      df << $1 if filename =~ %r{(\.[a-zA-Z0-9]+)$}
+    end
+    df
+  end
 end
diff --git a/test/unit/attachment_test.rb b/test/unit/attachment_test.rb
new file mode 100644
index 0000000000000000000000000000000000000000..99f7c29f95c78bf92f378f27c41c36baf3b77ffc
--- /dev/null
+++ b/test/unit/attachment_test.rb
@@ -0,0 +1,32 @@
+# redMine - project management software
+# Copyright (C) 2006-2007  Jean-Philippe Lang
+#
+# 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., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+
+require File.dirname(__FILE__) + '/../test_helper'
+
+class AttachmentTest < Test::Unit::TestCase
+
+  def setup
+  end
+  
+  def test_diskfilename
+    assert Attachment.disk_filename("test_file.txt") =~ /^\d{12}_test_file.txt$/
+    assert_equal 'test_file.txt', Attachment.disk_filename("test_file.txt")[13..-1]
+    assert_equal '770c509475505f37c2b8fb6030434d6b.txt', Attachment.disk_filename("test_accentué.txt")[13..-1]
+    assert_equal 'f8139524ebb8f32e51976982cd20a85d', Attachment.disk_filename("test_accentué")[13..-1]
+    assert_equal 'cbb5b0f30978ba03731d61f9f6d10011', Attachment.disk_filename("test_accentué.ça")[13..-1]
+  end
+end