I’d like explore the topic of electronic documents, digital signatures, and what properties are required of them them to be considered accurate and reliable written records. Since this is as much a social question as it is a technical one, we’ll start with some history.
“An Act for prevention of Frauds and Perjuryes” 29 Carol. II (1677), commonly called “The Statute of Frauds”, begins:
For prevention of many fraudulent Practices which are commonly endeavoured to be upheld by Perjury and Subornation of Perjury Bee it enacted by the Kings most excellent Majestie by and with the advice and consent of the Lords Spirituall and Temporall and the Commons in this present Parlyament assembled and by the authoritie of the same That from and after the fower and twentyeth day of June which shall be in the yeare of our Lord one thousand six hundred seaventy and seaven All Leases Estates Interests of Freehold or Termes of yeares or any uncertaine Interest of in to or out of any Messuages Mannours Lands Tenements or Hereditaments made or created by Livery and Seisin onely or by Parole and not putt in Writeing and signed by the parties soe makeing or creating the same or their Agents thereunto lawfully authorized by Writeing, shall have the force and effect of Leases or Estates at Will onely and shall not either in Law or Equity be deemed or taken to have any other or greater force or effect, Any consideration for makeing any such Parole Leases or Estates or any former Law or Usage to the contrary notwithstanding.
Or, to loosely paraphrase in modern English: “We’ve noticed that verbal agreements are being abused. So in certain specific important agreements you better put it in writing and sign it, otherwise don’t bother to bring any dispute to court.”
A few things to note about the Statute and its context:
- As the preface notes, frauds were being perpetrated, involving oral contracts and perjury. Before this Statute, oral testimony, even without any evidence of a written agreement, could be used to deprive a person of real or personal property.
- The Statute is concerned with private agreements. Although it was already well-established practice by this time for official acts, writs, etc., to be recorded in written form and sealed, literacy, even among tradesmen, was not high, and private agreements were made only orally.
- The imposition of a stamp duty or tax to seal official documents, followed this Statute a few years later, ostensibly to raise funds to fight a war against France. But like all forms of taxation, they seem to outlive their original intent, and exist even to the present day, even though England apparently is now at peace with France.
This Statute spread to the American Colonies, where in modified form it lives on in various state laws, and in the Uniform Commercial Code (UCC) today, in §2-201:
A contract for the sale of goods for the price of $5,000 or more is not enforceable by way of action or defense unless there is some record sufficient to indicate that a contract for sale has been made between the parties and signed by the party against which enforcement is sought or by the party’s authorized agent or broker.
I’d like to look a little at what it is about a written agreement that gives it its particular value. Why did they require it to be written? Why not just require witnesses to an oral agreement?
A few salient properties of a written agreement:
- A written agreement states the parties to the agreement, the terms of the agreement and is signed by the parties.
- Once signed, the agreement may not be altered but by mutual consent of the parties. In the judgement of Brett v. Ridgen, Plowd. Comm., 345, Lord Dyer wrote that “…men’s deeds and wills, by which they settle their estates, are the laws which private men are allowed to make, and they are not to be altered, even by the King in his court of law or conscience. We must take it as we find it.”
- The “mirror image” rule applies. Both parties must agree to the same terms. If part A makes an offer, and party B says they accept, but in fact adds or qualifies the terms of the offer, then this is properly treated as a counter-offer. The agreement is not made until both parties agree to the same terms.
- The underlying mechanics and notation of the agreement are flexible, unless otherwise specified. Whether scribbled with a crayon on a napkin, sent by telegram, teletype, fax or email, these may all be considered written agreements.
The affordances of paper and ink, which lends itself particularly well to the above concerns include:
- Paper/ink expresses symmetric information. What you see is what I see and is what will be seen in court if we end up there some day.
- There is no invisible ink, no hidden pages. The text of the agreement does not say something different under the florescent lights at the court house versus the sunlight at the construction site. Although these things in theory could be done, via special inks and papers, the use of these techniques in an agreement would be prima facie evidence of fraud.
- Certainly, if it is poorly written, the terms of the agreement could be ambiguous and subject to various interpretations. Paper/ink cannot make you or your lawyer smarter. It only makes the agreement an accurate and reliable record. If a particular word is smudged or a number is crudely written, I can see this flaw and you can see this flaw and either of us can require the flaw to be fixed before we sign the agreement. If there is text that is unclear in meaning, I can ask my lawyer to explain it. I am able to understand the document perfectly should I take care to do so.
- Paper/ink is accurate and reliable over the time scale of personal and commercial contracts.
- A person’s signature or mark on an agreement, absent evidence of fraud or coercion, clearly indicates their assent to the terms of the agreement. We do not commonly write our signature unless we intend to express assent.
Jump ahead to the present day, with the increasing use of electronic documents and digital signatures. Digital signatures offer some of the same affordances we traditionally had with paper/ink. Provided the chain of certificates and keys have not been compromised, that the underlying applications have not been compromised and that the act of signing requires an affirmative and unambiguous action by the signer, a digital signature is evidence of:
- What was signed
- Who signed it
- the intention to sign, i.e., give validity to the agreement
However, there is a weakness in electronic agreements, even when digitally signed. The weakness is in what is signed. When you sign a electronic document, you are signing the stream of bits and bytes that comprise that document in a particular document format. The average person lacks the ability to directly inspect or understand the underlying representation of an electronic document. They can only see what a particular software application running on a particular operating system running on a particular computer shows when loading the document. Will that signed document appear the same on a different computer, to a different person using a different software application or a different operating system? That is the critical question. Unfortunately, the affordances of paper/ink for symmetrical information, lack of hidden information, invariability over time and venue changes, etc., are not necessarily guaranteed with electronic documents.
The digital signature guys call out an additional requirement needed for a digital signatures to give the same guarantees as paper/ink agreements. It goes by the acronym WYSIWYS, or “What You See is What You Sign”.
So what is required for electronic documents to have the same affordances as paper/ink for use as accurate and reliable records? I suggest the following:
- The format used by the electronic document must be specified in an open standard.
- The format standard must define the characteristics of semantically equivalent documents and specify the format sufficiently so that implementations of the standard can display semantically equivalent renderings of the document. Semantic equivalence is not broken by minute differences in layout, so it should be possible to have semantically equivalent renderings on different devices, e.g., a laptop versus a smart phone versus a screen reader.
- The application used to view and sign the electronic document must conform to standard, specifically those stated parts of the standard necessary to render a semantically equivalent document.
- The document must be strictly conformant to the standard, with no extensions. Just as you would not physically sign a paper document that contained interpolated text in a language that you do not understand, you should not sign an electronic document that contains unknown extensions. Otherwise semantic equivalence is not guaranteed between the two parties and a “mirror image” problem.
- Semantic equivalence must not rely on graphics. Although graphical content is permissible, such content must be redundant with respect to the text. Otherwise the “mirror image” problem is unresolvable between sighted and blind persons.
Further, I believe these criteria are of more general applicability. Although the Statute of Frauds may have been intended for marriage contracts and the like, the need to have accurate, reliable written records is a ubiquitous requirement for business and public administrations today. Wherever misunderstanding would be liability, where it is particularly important for multiple parties to be “on the same page” with respect to the contents and meaning of a document, these considerations apply.
For editable formats like ODF, I think it points out the need to describe a formal content model that describes the semantic content of a document, aside from its formatting and layout. So text + lists + tables + headers + footers + footnotes + images + captions, etc. Visual appearance is nice to have as well, but it is less robust when rendered on different devices, different operating systems, and is less likely to be robust when rendered on OpenOffice 10.0 in 2015. But the equivalence of the semantic content of an unextended ODF document should provide the same ability to have an accurate and reliable record in an electronic document as we have had traditionally with paper and ink.