Patent ID: 8209762

Claim:
A printing device comprising: a user interface module, communicatively coupled with a local memory, the user interface module configured to: display information to users and recipients; receive user authentication data; authenticate the user using the user authentication data; in response to successful authentication of the user authentication data, cause retrieval of a user private key associated with the user; a scanning module, communicatively coupled with the local memory, the scanning module configured to: scan a printed document and store it in the local memory as an electronic document; a locked print module, communicatively coupled with the local memory, the locked print module configured to: generate a first hash code of the electronic document; generate a digital signature using the user private key to encrypt the first hash code of the electronic document; in response to a user input received from the user who provided the printed document, generate recipient data that specifies one or more intended recipients of the electronic document, a number of copies of the electronic document that each recipient is allowed to print, and user identification data that identifies the user of the electronic document, and store, in the printing device, the digital signature and the recipient data in association with the electronic document; cause sending of an electronic notification to each of the one or more intended recipients of the electronic document, wherein the electronic notification indicates that the electronic document is available for printing; in response to successful authentication of the recipient and selection by the recipient of the electronic document from a list of documents displayed for the recipient: retrieve the electronic document and the digital signature from the printing device, and from the recipient data, retrieve the user identification data; using the user identification data, retrieve a user public key; using the user public key, decrypt the digital signature to recover the first hash code; generate a second hash code using the electronic document; determine whether the first hash code matches the second hash code; in response to determining that the first hash code matches the second hash code, allow the recipient to print up to the number of copies of the electronic document.