<oembed><type>rich</type><version>1.0</version><author_name>npub1ac86vemj7ce5z8jyxt39rna3tvwql6xd30ha3vxcd6esysp23d9qrlswfj</author_name><author_url>https://nostr.ae/npub1ac86vemj7ce5z8jyxt39rna3tvwql6xd30ha3vxcd6esysp23d9qrlswfj</author_url><provider_name>njump</provider_name><provider_url>https://nostr.ae</provider_url><html>📅 Original date posted:2014-03-20&#xA;📝 Original message:Whats a sensible limit on practical/convenient QR code size?&#xA;&#xA;How much of the payment protocol message size comes from use of x509?&#xA;&#xA;(Just exploring what the options are).&#xA;&#xA;Adam&#xA;&#xA;On Thu, Mar 20, 2014 at 11:36:09AM +0100, Mike Hearn wrote:&#xA;&gt;   Encoding entire payment requests into qrcodes is definitely not the way&#xA;&gt;   to go. They can already be large when signed and we&#39;re just at the&#xA;&gt;   start of adding features.&#xA;&gt;   Finishing off and standardising the bluetooth support is the way to go&#xA;&gt;   (r=bt:mac). Andreas&#39; app already has some support for this I believe,&#xA;&gt;   so Alex you could prototype with that, but we need to:&#xA;&gt;   1) Add an encryption/auth layer on top, because it runs over RFCOMM&#xA;&gt;   sockets. The authentication would require proof of owning the Bitcoin&#xA;&gt;   key that&#39;s in the address part of the URI (which is needed for&#xA;&gt;   backwards compat anyway).&#xA;&gt;   2) Write a BIP for it and make sure it&#39;s interoperable&#xA;&gt;   For the auth layer we could either use SSL and then just ignore the&#xA;&gt;   server certificate and require signing of the session public key with&#xA;&gt;   the Bitcoin key, which should be easy to code up but is rather heavy on&#xA;&gt;   the air, or roll a custom lightweight thing where we just do a basic&#xA;&gt;   ECDH, with the servers key being the same as the address key. But&#xA;&gt;   rolling such protocols is subtle and I guess it&#39;d need to be reviewed&#xA;&gt;   by people familiar with such things.&#xA;&gt;   This feels like a good opportunity to grow the community - perhaps we&#xA;&gt;   can find a volunteer in the forums who enjoys crypto.</html></oembed>