Waterloo does have a strong Math tradition. But further to that, for a long time the Computer Science degree at Waterloo was a specialization under their Bache

Waterloo does have a strong Math tradition. But further to that, for a long time the Computer Science degree at Waterloo was a specialization under their Bachelor of Mathematics degree. So you had to fulfill all of the requirements of the Math program and graduated with a "BMath". You were also offered interesting minors like "Combinatorics and Optimization" where you would get deep into Cryptography, Graph Theory and so on. I can't say how it compares to other schools, but certainly many of my memories of CS at Waterloo were working feverishly through difficult math assignments so I could get back to the lab. ;)