In 1993 Adobe Systems published version one of the Portable Document Format specification, the PDF file that comprises a set of objects. A key design consideration was to enable the file to be created with a single pass. The specification included an incremental update to allow files to be updated without going back and deleting previous objects, it was also designed to be extensible. Now at version 2.0 the PDF Specification is an ISO specification with a rich set of features included support for digital signatures and collections of documents and data.
In 2009 David Siegal in his book Pull describes “The Personal Data Locker” and how it might be used to enable an individual to control and share their information with other parties. Although published after Satoshi Nakamoto’s 2008 paper it makes no reference to distributed ledgers or any other implementation technology.