Keyczar is meant to solve a different problem. It’s meant to be a simple programmatic API for crypto operations, while being high-level and excluding unsafe options. NaCl (http://nacl.cr.yp.to/) has similar goals to Keyczar.

Keywhiz isn’t an interface for software to do crypto. Rather, it’s a system to manage the secrets/keys used for crypto and making them available to the services that need them. It doesn’t explicitly look at the content of secrets, unless a plugin is used.