Wouldn't need to. The <rate> is of BTC to <currency>. BTC is the intermediary currency, as is basically how it becomes in this "payment rails" method.
To the receiver, it wouldn't matter what currency the transaction came from. 



On Tue, Sep 15, 2015 at 8:48 PM, Angel Leon <gubatron@gmail.com> wrote:

might want to specify there that the rate being sent is out of USD.

http://twitter.com/gubatron

On Tue, Sep 15, 2015 at 7:10 AM, John Bailon via bitcoin-dev <bitcoin-dev@lists.linuxfoundation.org> wrote:
Hello,

I'd like to propose a BIP for a standard URI scheme to allow wallet operators that implement instant exchange or pegging to other currencies, cryptocurrencies or asset classes to allow for interoperable communications of rates and other pertinent information.

The idea is to include in the wallet address as parameters information that supplements the presentation of a proposed transaction.

For example, a wallet operator that instantly exchanges bitcoin to gold would present a wallet address as follows:
bitcoin:1JohnxNT6jRzhu3H1wgVFbSGKmHP4EUjUV?currency=xau&rate=0.2084&expires=1458432000

Wherein:
<currency> :  the currency, cryptocurrency or asset that the transaction will end up as encoded in ISO 4217 if applicable.
<rate> : the bitcoin to <currency> rate as dictated by receiving wallet
<expires> : unix timestamp of when the rate loses validity

This would allow the sending wallet the ability to present up-to-date exchange rates. When, for example, a wallet operator that pegs to the USD scans the address above, it would be able to present to the user the following information:

1. USD to XAU rate
2. How much XAU will be received by the address
3. How long before the rates expires


Thoughts?


Regards,
John

_______________________________________________
bitcoin-dev mailing list
bitcoin-dev@lists.linuxfoundation.org
https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev