Inspired from GMail label pattern

I am going to follow Gmail label pattern. So:

<>: has a relation
(): composite type

system <> 1 ----------- 1-* entity
entity <> 1 ----------- 1 (name 1 -------------- 1 secret-value)
entity <> 1 ----------- 0-* label
label <> 1 ----------- 1-* entity

So from UI perspective labels will allow filtering. Example passwords in labels 'bank', 'joe', 'email'..etc.

No need to have complex tree structures, and tree navigation. Stick to Google paradigm. Be smart and follow the smart guys..