Well, the way that I read it is that everyone has the right to
A nationality. That is to say, at least according to the UN, they can't be stripped of citizenship if they are not citizens of at least two nations. In practice, I believe this is interpreted to mean that a state can only strip someone of a citizenship that has been granted after their birth. Or, at the very least, from the point of view of this particular armchair lawyer, by Canada at least, I am unsure about how other nations deal with this issue.
The core RIGHT is to be a citizen of the country of your birth. Along with that, you have a secondary right not to be arbitrarily stripped of citizenship of any other country which you subsequently become a citizen of.
And this particular 2ndary right is very likely one of the reasons that it is so difficult to become a citizen of Canada. Because if the government makes a mistake and grants citizenship to the "wrong" person, then we're stuck with them for quite some time. Simply becoming a criminal after the fact is, if I recall correctly, not enough justification to strip an immigrant of their citizenship. You have to prove that said citizenship was obtained under "false pretenses". For example, this article (http://www.rickdykstra.ca/index.php?option=com_content&task=view&id=446&Itemid=51&date=2009-11-01) outlines the story of two men who were stripped of their citizenship after it was proven that they lied about their past as SS Concentration Camp Guards during WWII when they were applying to become citizens. You can rest assured that quite a lot of money was spent on their cases.
So, yeah. I can't say whether or not there's some hideous undiscovered crime lurking in your past that threatens to strip you of your Canadian citizenship, but I'm just going to go out on a limb here and say that you're probably safe. As for Mr. Arar, he also still retains his Canadian citizenship. Yes, he was deported to Syria, and underwent a rather unpleasant time as a result. But the key is that he was deported to Syria by the Americans, from America. They could have also simply deported him back to Canada as well. As for the fact that this was done partially based on information provided by our government, but then again, our courts have decided rather decisively that this was an error on our part as well.
So yeah. To sum up, only place you can exile Canadians to is prisons within our borders.