Document meta-data repository

A system for protecting sensitive documents comprising:

• a server;
• a database;
• a first user interface device;
• and
• a second user interface device,
• wherein a first document is identified at the first user interface device,
• the first user interface device generates a registration key comprising a digital fingerprint and metadata for the first document, and transmits the registration key to the server, and wherein the first document is not transmitted to the server,
• the server stores the registration key and the metadata for the first document at the database,
• a second document is identified at the second user interface device,
• the second user interface device generates a production key comprising a digital fingerprint and metadata for the second document and transmits the production key to the server, and wherein the second document is not transmitted to the server, and
• the server produces an alert if the digital fingerprint of the production key is identical to any digital fingerprint of a registration key stored in the database,
• wherein the alert comprises the registration key for the first document or the production key of the second document.