Idea for alternative bitcoin address format for vendors

[realnowhereman]

Bitcoin vendors (should) generate a new address for each transaction.

They will say something like

Please send 2.57BTC to 1AAZ4xBHbiCr96nsZJ8jtPkSzsg1CqhwDa

Now... very sensibly, Bitcoin addresses are self consistent, making it very hard to mistype one and send the money to someone other than you intended.

But... the amount can still be mistyped.

How about this then?  A new address format which includes the amount and the address, both checksummed?

Please cut and paste this address zdfga1AAZ4xBHbiCr96nsZJ8jtPkSzsg1CqhwDa

It would be an extra few bytes at the end of the address, and it would be entirely UI-based, never getting anywhere near the block chain.  But it would mean that a customer could cut and paste the address given by the vendor into the Bitcoin client (or any of the online wallets if it became standardised) and the amount field would be automatically filled in, along with the "true" bitcoin address.  Obviously it would still need confirmation from the user, but it would make accidents like "Ooops I just sent 100 BTC when I meant to send 10 BTC to a vendor" much less likely; and much easier for Grandmas to use.

It could be easily handled by making a new bitcoin address version byte; which would trigger the special handling in the client(s).

[Meni Rosenfeld]

Wonderful idea.

Maybe we should also make it impossible to send twice to the same extended address. (But to maintain the ability to send two separate transactions of the same amount to the same real address, maybe the extended address should also contain some random stuff).

[wumpus]

Pretty neat idea.

Though if the amount is encoded into it in unreadable form, the client should show the details after pasting and give you the chance to confirm/reject the transaction.

[realnowhereman]

Though if the amount is encoded into it in unreadable form, the client should show the details after pasting and give you the chance to confirm/reject the transaction.

Without a doubt.  I wasn't very clear, but that's what I meant with "the amount field would be automatically filled in".

Maybe we should also make it impossible to send twice to the same extended address. (But to maintain the ability to send two separate transactions of the same amount to the same real address, maybe the extended address should also contain some random stuff).

Good idea.  The current time could be encoded in to it too, to some pre-chosen resolution.. I'd pick nearest hour.  Then the client could also warn the user that the address they are sending to is six months old.

[Pieter Wuille]

I think a bitcoin: URI is much more suited than the binary format intended for addresses.

[Luke-Jr]

How about "<a href='bitcoin:1AAZ4xBHbiCr96nsZJ8jtPkSzsg1CqhwDa?amount=5X5'>Click here to pay (5 mBTC)</a>"

[ene]

This is what URIs were invented for. Hopefully the bitcoin: URI will be implemented soon.