comments on Don's "Cypher Bank"

[yanek@novavax.nova.edu (Yanek Martinson)]

> address; and offer to accept deposits by cash, check, or what have
> you.  With the deposit, write on it your PGP handle.  Email me your 
> public key corresponding to the handle on the deposit.

A better way would be to mail the public key itself, or a short 
hash of it along with your payment.  That is all the information that
would be required.  A "handle" would be completely optional. 
If only the hash value is mailed, then the full key can be e-mailed
or anonymously posted to a newsgroup that you montitor.  If the full key
is mailed, you should invest in a scanner and some simple OCR software.

This way, someone may print out the public key and mail it to you.

> I will maintain a public list showing handles vs. Amount received,
> in collection, and in escrow.(Set Subject = "BANK" to get the list)

You should not disclose someone's balance to anyone else, and certainly
no to the public.  Someone requesting their balance should send the
request by any communications channel (anonymous mail, newsgroup, anything)
and sign it with the private key corresponding to the public key used
when making the deposit.  Then you should encrypt your reply (the account
balance & any other info) using the public key, and send it back through
any channel.

> Funds will be paid out based on instructions encyphered with your 
> private key.

I would make it: funds will be transferred based on instructions _signed_
with the private key corresponding to the public key used for deposit.

P.S. this would be equivalent to digital checking accounts.  Do not confuse
this scheme with the much more interesting Digital Cash ideas.

--
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