Cas Cremers

  1. What is the difference between Scyther, Scyther-proof, and Tamarin? Which one should I use?

    The differences and examples of use cases are summarised in the comparison table.

  2. I would like to use the Scyther tool for teaching at my university. Where should I start?

    There are ready-made exercises available from the exercise page. The solutions for these can be requested by teachers by e-mailing Cas Cremers.

  3. I get the following error "Image file is not of type 15" when I try to view attacks.

    The GraphViz ( installation on the system apparantly lacks bitmap output support. A clean install using the downloadables from the graphviz website should solve the problem.

    On some systems, including Red Hat Enterprise (5) systems, this particular error seems to be caused by a lack of bitmap output support in the default graphviz RPM. Two solutions have been reported to work:

    1. Install the optional graphviz-gd package, or
    2. Install the Fedora Core 6 RPM for graphviz. This supposedly installs cleanly on Red Hat Enterprise systems.

  4. I get an error stating "cannot determine EPS bounding box"

    Some Linux/OS X users have encountered the following error:

    in _open
       raise IOError, "cannot determine EPS bounding box"
    IOError: cannot determine EPS bounding box

    Note: this will be fixed in the next release.
    This error seems to be related to the automatic resizing of attack outputs by the PIL library. The problem seems to occur only in very recent versions of the PIL library.

    The following patch does not really fix it, but simply disables the resizing. In the file 'gui/Gui/', find the line that says

      havePIL = True

    and change it to say

      havePIL = False

    This should make the attack output work (but disables the 'zoom to fit' feature).

  5. How to run Scyther on Mac OS (64 bit)

    Some users upgraded to Mac OS 10.6 or later and reported that Scyther stops working (could not find wxpython). The cause is that the wxPython library can only be imported if Python is running in 32-bit mode. The easiest solution is:

    1. In a terminal, type the following and press enter:
      defaults write Prefer-32-Bit -bool yes

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People using Scyther are recommended to subscribe to the Scyther-users mailing list. If new versions of the tool are released, an announcement will be made on the mailing list.