Agree on importance of correlating records across heterogenous systems. AND: All PII field level data must be encrypted at rest. UUIDs unlock both the record

Agree on importance of correlating records across heterogenous systems. AND: All PII field level data must be encrypted at rest. UUIDs unlock both the record linking and privacy achievements. The book Translucent Databases shows how. Hide sensitive data with salt + hash, just like with proper password files. Use UUIDs as opaque pointers for linking.