16.24.1. Escrow Agents as a way to deal with contract renegging
- On-line clearing has the possible danger implicit in all
trades that Alice will hand over the money, Bob will verify
that it has cleared into hisaccount (in older terms, Bob
would await word that his Swiss bank account has just been
credited), and then Bob will fail to complete his end of
the bargain. If the transaction is truly anonymous, over
computer lines, then of course Bob just hangs up his modem
and the connection is broken. This situation is as old as
time, and has always involved protcols in which trust,
repeat business, etc., are factors. Or escrow agents.
- Long before the "key escrow" of Clipper, true escrow was
planned. Escrow as in escrow agents. Or bonding agents.
- Alice and Bob want to conduct a transaction. Neither trusts
the other;
indeed, they are unknown to each other. In steps "Esther's
Escrow Service." She is _also utraceable_, but has
established a digitally-signed presence and a good
reputation for fairness. Her business is in being an escrow
agent, like a bonding agency, not in "burning" either
party. (The math of this is interesting: as long as the
profits to be gained from any small set of transactions is
less than her "reputation capital," it is in her interest
to forego the profits from burning and be honest. It is
also possible to arrange that Esther cannot profit from
burning either Alice or Bob or both of them, e.g., by
suitably encrypting the escrowed stuff.)
- Alice can put her part of the transaction into escrow with
Esther, Bob can do the same, and then Esther can release
the items to the parties when conditions are met, when both
parties agree, when adjudication of some sort occurs, etc.
(There a dozen issues here, of course, about how disputes
are settled, about how parties satisfy themselves that
Esther has the items she says she has, etc.)
16.24.2. Use of escrow services as a substute for government
+ as in underworld deals, international deals, etc.
- "Machinery of Freedom" (Friedman), "The Enterprise of
Law" (Benson)
- "It is important to note in any case that the use of third-
party escrow as a substitute for Government regulation was
a feature of the Northern European semi-anarchies of
Iceland and Ireland that have informed modern libertarian
thought." [Duncan Frissell, 1994-08-30]
16.24.3. Several people have raised the issue of someone in an
anonymous transaction simply taking the money and not
performing the service (or the flip side). This is where
_intermediaries_ come into the picture, just as in the real
worl (bonds, escrow agents, etc.).
16.24.4. Alice and Bob wish to conduct an anonymous transaction; each
is unknown to the other (no physical knowledge, no pseudonym
reputation knowledge). These "mutually suspicious agents," in
1960s- and 70s-era computer science lingo, must arrange
methods to conduct business while not trusting the other.
16.24.5. Various cryptographic protocols have been developed for such
things as "bit commitment" (useful in playing poker over the
phone, for example). I don't know of progress made at the
granularity of anonymous transactions, though. (Though the
cryptographic protocol building blocks at lower levels--such
as bit commitment and blobs--will presumably be used
eventually at higher levels, in markets.)
16.24.6. I believe there is evidence we can shorten the cycle by
borrowing noncryptographic protocols (heresy to purists!) and
adapting them. Reputations, for example. And escrow agents (a
form of reputation, in that the "value" of a bonding entity
or escrow agent lies in reputation capital).
16.24.7. if a single escrow agent is suspected of being untrustworthy
(in a reputation capital sense), then can use _multiple_
escrows
- with various protocols, caveat emptor
- n-out-of-m voting schemes, where n escrow agents out of m
are required to complete a transaction
- hard to compromise them all, especially if they have no
idea whether they are being "legitimately bribed" or merely
pinged by a reputation-rating service
- Hunch: the work of Chaum, Bos, and the Pfaltzmanns on DC-
nets may be direcly applicable here...issues of collusion,
sets of colluders, detection of collusion, etc.
By Tim May, see README
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