Rainbow tables are password cracking tools with origins dating back to research from the early 1980s. Here's how they work and why they haven't stood the test of time.

I want to have a very large hash table, i.e. so big it won't fit into memory. What's a good way to do that? I could use a database, but since it's only going to be key => value pairs that I am ...

Making fast hash tables in programming, which don't cause collision trouble, is one of computing's holy grails. Facebook thinks it's created a good one.