Hey, I started writing on the subject of using Bitcoin w/o local internet, or when only one side has internet, or using HAM radio, SMS, Starlink, Blockstream Satelite, meshnet, mailing someone an opendime... any way bitcoin has been sent under these kind of non-typical ways.
If you folks know of any more lesser known projects or experiments like this, sending a link to any article/writeup/website/video/podcast would be appreciated.
My goal is to raise awareness of progress that Bitcoiners have made to deal with future possible no internet, low internet, or sporadic internet situations. In doing so, maybe encourage more work in this field. Internet shutdowns and slowdowns for political reasons are becoming more common.
Note: I have already googled the hell out of "Bitcoin without internet," "offline Bitcoin," "Lightning offline," that kinda thing.
Thanks, and have a great night!
Satscard, is like an OpenDime where it can be passed person-to-person, offline.
But with satscard the funds can be spent, and then a new address generated. That can be done sequentially for a total of 10 uses: https://satscard.com/faq
There are other approaches with other technologies:
Between a Rock and a Hard Place: Offline Use in CBDCs https://www.progressoft.com/blogs/between-a-rock-and-a-hard-place-offline-use-in-cbdcs
Blockchain side implementation of Pure Wallet (PW): An offline transaction architecture https://www.sciencedirect.com/science/article/pii/S2405959521000928
Scrit (also referred to as Scrit1), which is referenced as "prior art" for Fedimint, has methods for "half-offline" (i.e., only sender online, or only recipient online), and offline (i.e., both offline, and could be done via paper / QR codes even).
"Scrit: A distributed untraceable electronic cash system" https://github.com/scritcash/scrit-whitepaper/blob/master/scrit-whitepaper.pdf
The Fedimint homepage also refers to "Scrit2" with having "receiver- and sender-initiated half-offline transactions".
And along these lines:
Transferable E-cash: A Cleaner Model and the First Practical Instantiation https://eprint.iacr.org/2020/1400.pdf
And there are a number of redeemable code / voucher / etc approaches, including:
LNCash https://ln.cash/how
I have used the Bitcoin SMS relay before:
https://rusnak.io/how-to-send-bitcoin-transactions-via-sms/
Just send a signed transaction to +1 (863) 248-2646 or +1 (863) BIT-COIN.
Unfortunately, the number is in the United States so it did cost me 0,86€ from Europe (excluding the blockchain fee) but it was worth the experience.
I think there should be numbers for every continent at least.
Thanks!!! Heres one of those for Africa. Near the end of the video, they show the numbers for several African countries. https://twitter.com/BitcoinEkasi/status/1562568332783468545?t=O3FhAGpWDQGubEMbs99Qsw&s=19
edit: The one in the video is Lightning (LNURL) . I didnt know they did mainnet sms relay in 2017. Thanks again!
A clarification:
Machankura is a USSD-based custodial bitcoin wallet. The mobile subscriber (user), whether on smartphone or feature phone, interacts with Machankura through USSD menus. The service supports LN deposits (via LN invoice created by website, or via Lightning address). It supports withdrawal ONLY via Lightning address. If the destination is a mobile number, or is to a @8333.mobi Lightning address, the service performs an internal ledger update.
In some of the countries supported by Machankura, a receipt for a transaction will be delivered via SMS, but other than that there is nothing else done with Machankura that involves SMS.
Machankura is a new service. Are you possibly referring to some other service?
Maybe he means the service mentioned by me since the article is from 2017
Yep
See also:
thought experiment: how to keep full node in sync without traditional internet? #72642
and
We need a real decentralized mesh network for censorship resistant Bitcoin usage #49841 https://twitter.com/bradmillscan/status/1551951097375358976 [Nitter]
and
Hardening Bitcoin against ISP censorship at the individual level? #62398
and
How to send Bitcoin transactions via non-internet channels #9251
and
How to send Bitcoin transactions via SMS #2298 https://rusnak.io/how-to-send-bitcoin-transactions-via-sms
and
bitcoinVend: Offline bitcoin vending machine #52425 https://github.com/arcbtc/bitcoinVend
and even
Bitcoin Offworld | Bitcoin Magazine #35643 https://bitcoinmagazine.com/culture/bitcoin-offworld
Jeeze, thanks so so much. This will keep me occupied for a while
Check out Samurai's TxTenna if you haven't already
Yeah, I have that one bookmarked to check out. thank you!
OK cool. I assume you also have machankura bookmarked? https://8333.mobi/
Yep! Thanks!
Another simple way (from my experience)
Use BlueWallet,
Yeah, presigned Bitcoin transaction. I never knew getting it was so easy. Thanks!
Stumbled across this
https://offline.cash/
I’m still waiting for my shipment but seems like a cool idea.
Wow, i like this idea. Seems to solve the trust issues that came along with the "casascius coins" from the early years.
Yeah Im excited to get this shipment and try it out because this could work in locations with no internet and limited mobile use
You have to trust that it’s legit, trust the security features, hope the recipient knows what it is, etc. but looks cool! Post how it goes when you get it!
Tool to send/receive onchain transactions via audio channels (eg HAM radio or satellite phones)
https://github.com/elsirion/modemtx