13 June 2011
Is BitCoin a Triple Entry System?
Date: Mon, 13 Jun 2011 23:03:59 +1000
From: Ian G <iang[at]iang.org>
To: jamesd[at]echeque.com, Crypto discussion list
<cryptography[at]randombit.net>
Subject: [cryptography] Is BitCoin a triple entry system?
On 13/06/11 12:56 PM, James A. Donald wrote:
> On 2011-06-12 8:57 AM, Ian G wrote:
>> I wrote a paper about John Levine's observation of low knowledge,
way
>> back in 2000, called "Financial Cryptography in 7 Layers." The sort
of
>> unstated thesis of this paper was that in order to understand this
area
>> you had to become very multi-discipline, you had to understand up
to 7
>> general areas. And that made it very hard, because most of the
digital
>> cash startups lacked some of the disciplines.
>
> One of the layers you mention is accounting.
Yes, so back to crypto, or at least financial cryptography.
The accounting layer in a money system implemented in financial cryptography
is responsible for reliably [1] holding and reporting the numbers for every
transaction and producing an overall balance sheet of an issue.
It is in this that BitCoin may have its greatest impact -- it may have shown
the first successful widescale test of triple entry [2].
Triple entry is a simple idea, albeit revolutionary to accounting.
A triple entry transaction is a 3 party one, in which Alice pays Bob and
Ivan intermediates. Each holds the transaction, making for triple copies.
To make a transaction, Alice signs over a payment instruction to Bob with
her public-key-based signature [3]. Ivan the issuer then packages the
payment request into a receipt, and that receipt becomes the transaction.
This transaction is digitally signed by multiple parties, including at least
one independent party [4]. It then becomes a powerful evidence of the
transaction [5].
The final receipt is the entry. Then, the collection of signed
receipts becomes the accounts, in accounting terms. Which collection
replaces ones system of double entry bookkeeping, because the single digitally
signed receipt is a better evidence than the two entries that make up the
transaction, and the collection of signed receipts is a better record than
the entire chart of accounts [6].
A slight diversion to classical bookkeeping, as replacing double entry
bookkeeping is a revolutionary idea. Double entry has been the bedrock
of corporate accounting for around 700 years, since documentation by a Venetian
Friar named Luca Pacioli. The reason is important, very important,
and may resonate with cryptographers, so let's digress to there.
Double entry achieves the remarkable trick of separating out mishaps from
frauds. The problem with single entry (what people do when making lists
of numbers and adding them up) is that the person can leave off a number,
and no-one is the wiser [7]. We can't show the person as either a bad
bookkeeper or as a fraudulent bookkeeper. This Achilles heel of primitive
accounting meant that the bookkeeping limited the business to
the size with which it could maintain honest bookkeepers.
Where, honest bookkeepers equals family members. All others, typically,
stole the boss's money. (Family members did too, but at least for the
good of the family.) So until the 1300s and 1400s, most all businesses
were either crown-owned, in which case the monarch lopped off the head of
any doubtful bookkeeper, or were family businesses.
The widespread adoption of double-entry through the Italian trading ports
led to the growth of business beyond the limits of family. Double entry
therefore was the keystone to the enterprise, it was what created the explosion
of trading power of the city states in now-Italy [8].
Back to triple entry. The digitally signed receipt dominates the two
entries of double entry because it is exportable, independently verifiable,
and far easier for computers to work with. Double entry requires a
single site to verify presence and preserve resiliance, the signed receipt
does not.
There is only one area where a signed receipt falls short of complete evidence
and that is when a digital piece of evidence can be lost. For this
reason, all three of Alice, Bob and Ivan keep hold of a copy. All three
combined have the incentive to preserve it; the three will police each
other.
Back to BitCoin. BitCoin achieves the issuer part by creating a distributed
and published database over clients that conspire to record the transactions
reliably. The idea of publishing the repository to make it honest was
initially explored in Todd Boyle's netledger design.
We each independently converged on the concept of triple entry. I believe
that is because it is the optimal way to make digital value work on the
net; even when Nakomoto set such hard requirements as no centralised
issuer, he still seems to have ended up at the same point: Alice, Bob and
something I'll call Ivan-Borg holding single, replicated copies of the
cryptographically sealed transaction.
With that foundation, we can trade.
> Recall that in 2005
> November, it became widely known that toxic assets were toxic.
In 2005, the SEC looked at my triple entry implementation, and....
> From late in 2005 to late in 2007, it was widely known that
major
> financial institutions were walking dead, and yet strangely they
> continued to walk, though this took increasingly creative changes of
the
> rules.
...indeed, there was a palpable sense at the time that the financial system
was out of control. They were looking at this thing with worried eyes.
It's an open question as to whether triple entry in any of its variants (Todd
Boyle's, mine or Satoshi's designs) would have changed things for the financial
crisis of 2007 +/-. I think the answer is; it was way too late
to effect it. But, it wouldn't have hurt, and with other things added
in [9], the sum would have changed things, assuming widespread implementation.
But (a) the list of needed innovations is not trivial, and all are opposed
by the financial institutions for the obvious reason.
Also, (b) it has to be said that at the bottom of the financial crisis is
securitization, which changes everything about finance [10]. And I
do mean everything :) Without understanding the role that securitization
plays, talking about triple entry or toxic assets or ratings agencies or
bad behaviour or poor people or whatever is pretty much doomed to irrelevance.
Which is how they like it!
> Today in 2011, there is still no audit that acknowledges that toxic
> assets were and are toxic.
This one winds all the way to [11] ...
> While doubtless a good monetary system should embrace all these
aspects
> of knowledge, our existing monetary system does not.
iang
Notes:
[1] Reliably here means to play its part in the overall security model against
attacks of fraud, etc.
[2] This rant is essentially a highly compressed version of:
http://iang.org/papers/triple_entry.html
[3] There is an intermediate step here where Bob can also sign the payment
into a deposit instruction, thus confirming acceptance. But this can
be optimised out.
[4] Think here of European Notaries, responsible to both parties to intermediate.
[5] Crypto people would recall the term "non-repudiable" although that is
out of favour; "non-repudiation is repudiated :). BitCoin paper uses
the term "non-reversible." Finance prefers terms like "final
settlement. Legal people look for "evidence." I choose the legal
term here because in a dispute their opinion matters more.
[6] This is not really apparent on paper, only in code and implementation
(aka issues).
[7] All of this logic is applicable & analogous & consistent when
the bookkeepers are computers...
[8] Accounting history does not accept this point as proven. Having
seen the difference of both double entry and triple entry in accounting systems,
I'd say its clear. But historians don't have the benefit of seeing
accounting systems stuff up in glorious fashion, they only have the dry old
parchments to work from.
[9] Another of the things essential on the list is final settlement /
irreversibility / non-repudiation, as pioneered in many digital cash
schemes. c.f., Mutual Funds Scandal.
[10] Everything important about the financial crisis in 4 short essays, start
here:
http://financialcryptography.com/mt/archives/001297.html
[11]
http://financialcryptography.com/mt/archives/001126.html
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