HCII2014 presentation http://2014.hci.international/

1. http://www.tlu.ee/dsl The Digital Safety Lab is supported by the Tiger University
Program of the Information Technology Foundation for Education.
File formats security - proprietary vs.
open-source
Edmund Laugasson
(presenter)
Tallinn University
Kaido Kikkas
Tallinn University
Estonian IT College
HCII 2014, Creta Maris, Heraklion, Crete, Greece

2. Background
● digital information is shared as a file online
● the file has a format
● how to choose such document file format, that is
legible for all?
● computer-based format vs. online formats – this
paper focuses on computer-based formats
(interoperability framework->discussion)

3. Common office programs and file formats
MS Office
● Text processing (MS Word)
– doc
– docx
● Spreadsheet (MS Excel)
– xls
– xlsx
● Presentation (MS Powerpoint)
– ppt
– pptx
– pps
– ppsx
LibreOffice
● Text processing (Writer)
– odt
● Spreadsheet (Calc)
– ods
● Presentation (Impress)
– odp
● Math formula (Math)
– odf
● Drawing (Draw)
– odg

4. source: http://xkcd.com/927/

5. Background
● Estonia has adopted the interoperability framework,
based on a similar EU document
● among others, it regulates file formats for public
sector
– OpenDocument formats (ODT, ODS, ODP etc) for editing
– Portable Document Format (PDF) for viewing, printing

6. Problems
● interoperability framework is optional, not
mandatory and therefore often ignored
● people are using file formats not legible for all
(ignoring interoperability framework)
● files can have enormous size, may be corrupted
and contain sensitive data
● digital literacy is affected by influence of different file
formats – regardless of user skills

7. source: http://www.explainxkcd.com/wiki/index.php/1301:_File_Extensions

8. Our study
● research was carried out in Estonia
● autumn 2013
● different office documents from public sector web sites
were analyzed
● why: file sizes were too big
● the hypotheses: MS Office files (doc, docx, rtf) can contain
deleted and possibly sensitive information – new content is
often created on top of old one. Also, the same files are
smaller in OpenDocument format.

9. Research method
● document files (mostly MS Office) from Estonian
public sector web pages were analyzed
● files were renamed for easier indexing
● file content were replaced with new one and
examined using Emacs and Midnight Commander
to find out the actual content
● file sizes were registered – both original and
changed files and results were compared

10. Research method
Operating systems used:
● 64-bit Ubuntu 12.04 LTS with 3.12.5 kernel
● MS Windows XP Pro SP3, 32-bit (as virtual
machine in VirtualBox on Ubuntu 12.04 LTS)
Other software used:
● MS Office 2003, 2010 (32-bit)
● LibreOffice 4.1.3.2 (64-bit)
● Emacs 23.3.1 (64-bit)
● Midnight Commander 4.8.1 (64-bit)

11. Results
● first hypotesis: deleted information will remain
inside file – was partially confirmed, as some
small parts will remain
● second hypotesis: when saving DOC, DOCX,
RTF into OpenDocument format ODT will reduce
file size – was also partially confirmed. Usually
DOC, DOCX will be smaller in ODT but RTF files
saved in ODT will be bigger in some cases
● biggest surprise was: RTF files saved into ODT
are occasionally bigger – this needs to be
investigated further

12. Conclusions
● using MS Office file formats do not leak sensitive
information but sizes are bigger than usually
expected
● saving MS Word documents into OpenDocument
will reduce file size in most cases
● keeping the same version of MS Word in all
institutions at public sector is quite expensive
● file sharing should not be based on importing-exporting
file formats – that is where the
interoperability framework comes in

13. Question for the wider public
● how is interoperability solved in your country?
– Do you have interoperability framework, that
regulates also used file formats?
– .... is it completely/partially fulfilled?
source: http://www.explainxkcd.com/wiki/index.php?title=1247:_The_Mother_of_All_Suspicious_Files

14. Thank you!
source: http://www.discoverhongkong.com/eng/images/plan-your-trip/large/5.4.5-Frequently-Asked-Questions_03.jpg
Contacts:
Edmund Laugasson
edmund.laugasson@gmail.com
Kaido Kikkas
kaido.kikkas@kakupesa.net
The Digital Safety Lab is supported by the Tiger University
Program of the Information Technology Foundation for Education.