What is the required group theory knowledge needed to understand Verhoeff's algorithm? The Wikipedia page tells me I need to understand permutation groups and dihedral groups. Can someone clearly outline what exactly the perquisites of understanding this is and how much time I'll take to understand this ?
I know some basic group theory. I don't know what dihedral groups are and I haven't studied information theory.

Bit of a strange question.  As (finite) groups go, I'd rate the family of Dihedral groups as the second easiest to get a handle on, after cyclic groups.  Only 2 generators - basically a rotation and a reflection of a n-gons. In any book on group theory you are still in an early chapter when you reach this topic :-)
For the agorithm itself, you need very little "group theory" per se. For example one could code the algorithm in java, perl, pascal, whatever without knowing any theory at all (not that I recommend it, but one could).
