- The meetup will take place on March 9th at Lamppost Coffee from 6-7PM and BrassTap from 7-??. - The agenda includes onboarding local businesses to accept bitcoin, discussing payment tools they can use, and a more technical discussion on swapping between Cashu mints to increase privacy on the Lightning Network. - Attendees are encouraged to connect their bitcoin full node and open a channel to help the roundrockbitcoiners node, as well as donate sats to help cover meetup costs.

1. Meetup # 10 – March 9, 2023
Meetup # 10 – March 9, 2023

2. 2
Agenda
Agenda
Mission: “Our mission is to share bitcoin knowledge, tools, and resources creating a peer to peer network of local bitcoiners within the Round Rock
community.”
Purpose
Our purpose is to grow bitcoin adoption by individuals and small businesses in a circular economy within our local community.
Location(s):
- Lamppost Coffee 6-7PM
- BrassTap – 7- ???
Rules:
No shitcoining
No pictures/video unless we agree ahead of time
Chatham house – speakers should not be attributed
Announcements:
OshiApp Lamppost Gift Cards
The Bitcoin Company Honey Badger – Free Sats!
Circular Economy (Satoshi Square) - Azteco Vouchers
Bitcoin Magazine Sponsorship – 50% Off Bitcoin 2023 & The Bitcoin Games - Miami
BTCPayserver for Donations
Stickers from MVDEX & Lucho Poletti
Questions:
Who has made an on-chain bitcoin transaction?
Who has made a lightning transaction?
Who is running a bitcoin full node?

3. 3
Connect to our node
Connect to our node
02dd5649b3b872024e6c9cac775fdea95f08c05a5fa9575e96e214b6a90baed438@z7wmavvxd
irafksqhm2mwmfvujymsfzwyf7tzitmrzfgn6fynn2fioqd.onion:9735
Open a channel with us and we will open one with you

4. 4
Donate some sats to our BTCPayserver
Donate some sats to our BTCPayserver
Goes to paying for our meetup costs and outreach

5. 5
Connect w/ us on Twitter @RBitcoiners
Connect w/ us on Twitter @RBitcoiners
Give us a follow!

6. 6
Find Us on NOSTR
Find Us on NOSTR
NIP-05 ID: roundrockbitcoiners@nostrplebs.com
NIP-05 ID: roundrockbitcoiners@nostrplebs.com
Npub17ysayggwumkpkpgsq75axd7ed9guw03wz9jldz5d0zrkgz0cja2qd09tzu
wss://nostr.roundrockbitcoiners.com
Is this the real Web 3.0?

7. 7
We have a new website!
We have a new website!
https://roundrockbitcoiners.com
Many thanks to Julie!!!

8. 8
Onboarding Local Businesses
Onboarding Local Businesses
What local businesses are currently accepting bitcoin?

9. 9
Onboarding Local Businesses
Onboarding Local Businesses
The problem
What are some potential solutions?

10. 10
Onboarding Local Businesses
Onboarding Local Businesses
- Existing
- Existing Opportunities
Opportunities
Ask a local business if they accept bitcoin
●
Never hurts to ask!
●
Some businesses are struggling with credit card processing fees for small transactions (Can be 1.5 – 3.5% of each transaction).
●
A good way to build a business treasury for future expansion. Just ensure they understand the long-term nature of their hodlings.
Farmer George Market
●
Round Rock: Saturdays between 10AM – 2PM
●
Behind Ikea
Wolf Ranch Farmers Market
●
Georgetown: Saturdays between 10AM – 2PM
●
Wolf Ranch Shopping Center
Other Farmers Markets
●
The Market at Indian Mound Ranch (Saturday, March 19th 9 am – 1 pm)
12805 SH 29 W Liberty Hill, TX
●
Texas Farmer’s Market at Lakeline: (Saturdays 9 am – 1 pm)
11200 Lakeline Mall Drive, Cedar Park, TX
●
Wilco Farmer’s Market: (Thursdays from 10 am -2 pm)
E 8th St, Georgetown, TX 78626
●
Eli’s Roadside Produce (Open Everyday)
Many food trucks that we can onboard
Can you think of any others?

11. 11
Onboarding Local Businesses
Onboarding Local Businesses
Oshi App
Oshi is a powerful marketing and rewards platform built to replace stars,
punch cards, and coffee points with something that people really want -
Bitcoin.
IbexPay
IBEXPAY is the easiest and fastest way for any business to accept instant
Bitcoin payments over the Lightning Network and On-Chain. Whether you
are a single location over the counter taco shop or a multinational clothing
chain with many managers and locations, IBEXPAY can work for you.
Open Node
Get lightning-fast, low-cost bitcoin payments and payouts for your business
with our powerful API, ecommerce plugins, or hosted payment pages.
Strike
Send and receive money instantly. Buy bitcoin. Get paid in bitcoin.
Cash App
The easy way to buy, sell, send, and receive bitcoin
What other payment tools can businesses use?

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What are some other ways to find local
What are some other ways to find local
businesses that accept bitcoin?
businesses that accept bitcoin?
Oshi App local map
●
Lists all the locations that
are currently accepting
bitcoin via the Oshi App.
●
Some businesses only
have gift card options to
purchase.
BTCMap
●
Open source project that
uses OpenStreetMap to tag
places where you can
spend bitcoin.
●
Much of the data is
outdated, so please help
verify!
Do you know of any other good resources?

13. 13
And now for a bit more technical topic:
And now for a bit more technical topic:
Swaps between Cashu mints
Swaps between Cashu mints
“Swaps between cashu mints are great for increasing privacy from an LN observer's perspective.
First understand that as long as transactions are done with Cashu tokens within the same mint or between
mints via swaps, privacy is perfect. In transactions within the mint itself, the mint does not know with whom
the tokens are being exchanged, and in swaps between mints the receiving mint also does not know the
origin of the swap, since the transaction is launched by the LN node where the first mint is located, and not
by the user.
Finally, there is the case of wanting to exchange the token in the second mint. In this case the LN node
where the mint operates performs a transaction towards our wallet or LN node, but from the point of view of
an LN observer, if we use different wallets or nodes between the first mint (sending over LN to create the
token) and the second one (redeeming the token through LN) there is no traceability.
Therefore, we can use swaps between mints to erase the traceability of our satoshis at a ridiculous cost
since we only pay LN fees and you can add as many hops between mints as you want to add obfuscation.
I add a small diagram to make it clearer.”

14. 14
Swaps between Cashu mints
Swaps between Cashu mints
By using 2 separate nodes, we can get perfect privacy

15. 15
What is Cashu?
What is Cashu?
Cashu is the protocol; Nutstash a wallet

16. 16
What is Cashu?
What is Cashu?
Based on David Chaum’s Blinded Signature Technology
Cashu is a free and open-source Chaumian
ecash system built for Bitcoin. Cashu offers
near-perfect privacy for users of custodial
Bitcoin applications. Nobody needs to knows
who you are, how much funds you have, and
with whom you transact with.

17. 17
What is Chaumian eCash?
What is Chaumian eCash?
David Chaum is associated with the invention of Blind Signature
Technology. In 1982, while studying at the University of
California, Berkeley, Chaum wrote a paper describing the
technological advancements to public and private key technology,
in order to create this Blind Signature Technology.[4] Chaum's
Blind Signature Technology was designed to ensure the complete
privacy of users who conduct online transactions. Chaum was
concerned with the public nature and open access to online
payments and personal information. He then proposed to
construct a system of cryptographic protocols, in which a bank or
the government would be unable to trace personal payments
conducted online.[5] This technology became fully implemented
in 1990, through Chaum's company, DigiCash.

18. 18
What is Chaumian eCash?
What is Chaumian eCash?
3 main characteristics of Chaumian eCash
(1) Inability of third parties to determine
payee, time, or amount of payments made by
an individual.
(2) Ability of individuals to provide proof of
payment, or to determine the identity of the
payee under exceptional circumstances.
(3) Ability to stop use of payments media
reported stolen.

19. 19
Some Wizardy: Sending and receiving blinded
Some Wizardy: Sending and receiving blinded
signatures (exercise)
signatures (exercise)
Chaumian eCash tokens - payer bank to payee’s bank

20. 20
How To Send ECash Tokens To Nostr Users
How To Send ECash Tokens To Nostr Users
1. Create wallet 2. Add a mint 3. Configure Nostr
https://wallet.nutstash.app/

21. 21
How To Send ECash Tokens To Nostr Users
How To Send ECash Tokens To Nostr Users
Successful receive over Nostr!
https://wallet.nutstash.app/