What reel and frame numbers have to do with bitcoin and blockchain and shared ledgers

For their entire careers, US patent and trademark practitioners have lived and breathed a world of “reel and frame numbers” that are somehow intimately connected with the recordation of patent and trademark assignments.  What exactly are reel and frame numbers, and how is it that reel and frame numbers relate closely with bitcoin and blockchain and shared ledgers? 

First I will remind the reader of a bit of history about reel and frame numbers as they relate to patent and trademark assignments.  Then I will remind the reader of the purpose of shared ledger and blockchain technology.  With a few words I will then invite the reader to see how closely related these concepts are.

To make sense of reel and frame numbers, we recall the world of Patent and Trademark Depository Libraries (PTDLs).    In 1998, there were 92 PTDLs, with at least one PTDL located in each of the fifty US states.  In Colorado, the PTDL happened to be the Denver Public Library.   Time having passed and progress having been made, of course the PTDLs needed to be renamed, and now they are called Patent and Trademark Resource Centers (PTRCs).

Before 1955, assignment documents at the USPTO were recorded in bound volumes.  The location of documents in these volumes was designated by “liber and page,” that is, by the number of the book (liber) and the number of the page in the book.  These “liber-and-page” pre-1955 records were transferred to the National Archives and Records Administration (“NARA”) in 1990.

The USPTO started recording assignments on microfilm in  1955.  The first recordation on microfilm was on January 3, 1955, and was at reel 1, frame 1.   The idea of the reel and frame numbers was that in the event of litigation or some title dispute, a party could proffer an “abstract of title”, which is one or more reel and frame numbers, as authority for the proposition that some particular entity is the owner of a trademark registration or a patent.  A skeptical party could invite the parties involved to travel together to any PTDL and to view and print out the documents whose images appeared at the cited reel and frame numbers on reels of microfilm at the PTDL.  The parties could then scrutinize the words appearing on the documents to arrive at their own views as to the ownership of the property in question.

By now in recent recordations by our firm, we have seen reel numbers as high as 63559.  Each reel has as many as ten thousand frames on it.  So something like sixty million frames of microfilm (or, in more recent years, digital imaging) have by now  taken place.

Of course a skeptical party could call into question the authenticity of the microfilm reels.  What if a sneaky person had tampered with one or more of the reels of microfilm, a skeptical party could ask?  Any doubts could promptly be laid to rest by having the parties involved travel together to a second PTDL and to view the documents appearing at those same reel and frame numbers.  Again, of course, a skeptical party could ask whether a sneaky person had tampered with the reels of microfilm at the second PTDL.  But eventually a group visit to a third or fourth PTDL would quiet even the most skeptical person.  The thought that three or even four librarians could all be bribed to permit tampering with such records is beyond the pale, I think.

The physical dispersion of the microfilm reels across a field of some 92 destinations also puts to rest any concerns about the consequences of a fire or other disaster befalling any one or two of the PTDLs.

Those who have made use of the system for recordation of patent and assignment documents on microfilm are aware that in various built-in ways the system is additive and is never subtractive.  Because of built-in procedural elements of the system, one can only add to the body of recorded documents, but a document once recorded can never be withdrawn from the body of recorded documents.  On a very practical level this goes hand in hand with the notion that once a given microfilm reel has been duplicated 92 times and physically distributed, it cannot be withdrawn.

Since 1955 it has been the job of the Assignment Branch at the USPTO to carry out the microfilm phototography of assignments, and other documents relating to title, for patents and trademarks.  Once a document has been photographed, a record is kept of the reel number of microfilm at which the document appears, and the frame number (the starting frame number) at which the document appears.  This precious “reel and frame number” is reported back to the party who submitted the document for recordation.

The Assignment Branch also provides a lookup facility.  An interested party can plug in a property number (such as an application number, or a patent number, or a trademark registration number) at the lookup facility, and if all goes well he or she can learn the reel and frame number for the document or documents that have been recorded gainst that property number.  One aspect of this lookup facility is that it shields from public view any information about assignment records for patent applications that are not (yet) public.

In 2016, the USPTO started to make the assignment records themselves available online.  This has the prospect of saving a member of the public from having to make a trip to a PTRC to get a copy of such a document, or having to pay money to order it up from the Assignment Branch.

This brings us around to blockchain technology, which is a specific example of what is more generally termed “shared ledger”.

The idea of “shared ledger” (sometimes called “distributed ledger”) is that some important set of information is replicated and distributed more or less continuously across a large number of locations (“nodes”).  At the beginning of this blog article I described a group of skeptical litigants who might hop into their cars and travel together to visit each of several PTDLs, examining reels of microfilm one by one until they arrived at consensus as to the true content of a set of documents. Underlying this is a set of duplicate copies of reels of microfilm, dispatched at periodic intervals from the Assignment Branch at the USPTO to each of 92 PTDLs.  An unspoken but underlying notion is that it would be physically awkward to tamper with particular frames of a reel of microfilm, and that attempted bribes of large numbers of librarians would be unlikely to go unnoticed and uncommented upon.

In today’s shared ledger environment, an identical function is provided.  The sole difference is that much of it happens in software.  Instead of dispatching physical reels of microfilm at periodic intervals, data packets get transmitted over computer networks.  Instead of relying upon the unlikeliness of successful bribes of large numbers of librarians, cryptographic signing mechanisms guard against tampering with the content of the data stored in the nodes.  Instead of vehicular road trips carried out by groups of skeptical litigants, the shared-ledger systems use “consensus algorithms” to work out the correct copy of the current ledger, drawing upon the known contents of the various nodes. Just as no central authority controls the nodes of a present-day shared ledger, in 1955 no central authority controlled the 92 city and university libraries that chose to serve as PTDLs.

What I term the “additive but not subtractive” element of the dispersed microfilm recordation system finds an exact counterpart in every real-life implementation of a shared ledger or a blockchain.  Any shared-ledger event, once distributed through the shared ledger, is “locked into” the body of shared past events.  In the terminology of the blockchain, the body of all past events in the chain is reduced to a checksum which is cryptographically signed and is added to the current block in the chain.  This freezes for all time the contents of the previous blocks, making imposible the present-day counterpart of bribing a number of librarians to try to tamper with a number of (or all) past microfilm reels.  As I say, this builds into the present-day systems that one can add events to the record but one may not delete or “remove” events from the record.

These are the defining characteristics of the blockchain, which underlies Bitcoin and most other cryptocurrencies.

Every time we carry out yet another assignment recordation, every time we follow the ritual of reporting the precious “reel and frame number” to our client, we are perpetuating a tradition, by now dating from as long ago as 1955, that underlies most of today’s cryptocurrencies.