Per CHEF-4011, one should add knife[:secret_file] to their knife.rb if they wish to use a single secret file across their data bags and for bootstrapping purposes.
If you add this entry to your knife.rb and try to show or edit a data bag that isn't encrypted, it results in the following message:
ERROR: Chef::EncryptedDataBagItem::DecryptionFailure: Error decrypting data bag value: 'wrong final block length'. Most likely the provided key is incorrect
Both editing and showing an encrypted data bag works fine.
It returns a 200:
DEBUG: ---- HTTP Status and Header Data: ----
DEBUG: HTTP 1.1 200 OK
DEBUG: server: nginx/1.2.3
DEBUG: date: Wed, 04 Dec 2013 00:29:42 GMT
DEBUG: content-type: application/json
DEBUG: transfer-encoding: chunked
DEBUG: connection: close
DEBUG: x-ops-api-info: flavor=osc;version=11.0.2;erchef=1.2.6
DEBUG: content-encoding: gzip
DEBUG: ---- End HTTP Status/Header Data ----
DEBUG: decompressing gzip response