📅 Original date posted:2015-02-06
📝 Original message:Agree, range is not an issue. The trade-off is in battery vs. total
time, which would be influenced primarily by the battery sensitivity of
the platform. I'll send you a note to follow up.
e
On 02/05/2015 05:40 PM, Andy Schroder wrote:
> Hello,
>
> I personally would prefer as low of range as possible for this bluetooth
> application considering the connection is not yet encrypted (mentioned
> below), and even if it were, it seems like it is always going to be
> better in case there is some vulnerability. From my testing with a
> bluetooth radio inside my metal cabinet, the range is ~5 meters, which
> is more than enough.
>
> However, the connection is actually a bit slow when the whole
> certificate chain is included (~3-4s). You can sort of see this in my
> video (http://youtu.be/kkVAhA75k1Y?t=7m39s). A lot of the time is
> actually spent verifying the signature, and I'm not sure how much of it
> is doing the fetching (I haven't done any detailed timings using "adb
> logcat" and looking at the log entries), but I do know it is a little
> slower than an HTTPS payment request fetch over wifi (~2-3s). The reason
> I know most of the time is the signature verification is because an
> HTTPS payment request fetch over wifi and verification using breadwallet
> on apple is much faster (<1s) than HTTPS payment request on bitcoin
> wallet on android (apparently apple has a significantly more optimized
> signature verification algorithm). Bottom line is that there may be ~1s
> time transferring the data with this current bluetooth connection. Not
> sure how slow it will be with the BLE connection. Time is everything in
> a point of sale application.
>
> So, I guess what I am saying is it seems like the lower speed and range
> gain with bluetooth low energy are not a benefit in my opinion. I'm not
> sure that the latency gain will be a benefit either unless the speed
> issues I am noticing with regular bluetooth are actually a latency issue
> with just getting the connection established, or actually transmitting
> the payment request data. How much power is going to be used for just a
> few second payment? It's not like the bluetooth connection is maintained
> for a long time like it may be in other non bitcoin use cases.
>
>
> Where is a more appropriate place to discuss the other issues you have
> at length?
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Eric Voskuil [ARCHIVE] /
npub1sg…ppx3c
2023-06-07 15:29:57
in reply to nevent1q…rj9d
Author Public Key
npub1sgs97fe0n9wehe6zw7drcxdz4cy9yt9pfqjv8gasz5jlk4zezc0quppx3cSeen on
wss://relay.noswhere.comPublished at
2023-06-07 15:29:57Event JSON
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"content": "📅 Original date posted:2015-02-06\n📝 Original message:Agree, range is not an issue. The trade-off is in battery vs. total\ntime, which would be influenced primarily by the battery sensitivity of\nthe platform. I'll send you a note to follow up.\n\ne\n\nOn 02/05/2015 05:40 PM, Andy Schroder wrote:\n\u003e Hello,\n\u003e \n\u003e I personally would prefer as low of range as possible for this bluetooth\n\u003e application considering the connection is not yet encrypted (mentioned\n\u003e below), and even if it were, it seems like it is always going to be\n\u003e better in case there is some vulnerability. From my testing with a\n\u003e bluetooth radio inside my metal cabinet, the range is ~5 meters, which\n\u003e is more than enough.\n\u003e \n\u003e However, the connection is actually a bit slow when the whole\n\u003e certificate chain is included (~3-4s). You can sort of see this in my\n\u003e video (http://youtu.be/kkVAhA75k1Y?t=7m39s). A lot of the time is\n\u003e actually spent verifying the signature, and I'm not sure how much of it\n\u003e is doing the fetching (I haven't done any detailed timings using \"adb\n\u003e logcat\" and looking at the log entries), but I do know it is a little\n\u003e slower than an HTTPS payment request fetch over wifi (~2-3s). The reason\n\u003e I know most of the time is the signature verification is because an\n\u003e HTTPS payment request fetch over wifi and verification using breadwallet\n\u003e on apple is much faster (\u003c1s) than HTTPS payment request on bitcoin\n\u003e wallet on android (apparently apple has a significantly more optimized\n\u003e signature verification algorithm). Bottom line is that there may be ~1s\n\u003e time transferring the data with this current bluetooth connection. Not\n\u003e sure how slow it will be with the BLE connection. Time is everything in\n\u003e a point of sale application.\n\u003e \n\u003e So, I guess what I am saying is it seems like the lower speed and range\n\u003e gain with bluetooth low energy are not a benefit in my opinion. I'm not\n\u003e sure that the latency gain will be a benefit either unless the speed\n\u003e issues I am noticing with regular bluetooth are actually a latency issue\n\u003e with just getting the connection established, or actually transmitting\n\u003e the payment request data. How much power is going to be used for just a\n\u003e few second payment? It's not like the bluetooth connection is maintained\n\u003e for a long time like it may be in other non bitcoin use cases.\n\u003e \n\u003e \n\u003e Where is a more appropriate place to discuss the other issues you have\n\u003e at length?\n\n-------------- next part --------------\nA non-text attachment was scrubbed...\nName: signature.asc\nType: application/pgp-signature\nSize: 473 bytes\nDesc: OpenPGP digital signature\nURL: \u003chttp://lists.linuxfoundation.org/pipermail/bitcoin-dev/attachments/20150205/d6426f9f/attachment.sig\u003e",
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