Connect with our node & ping us on telegram 

Objective Mission: “Our mission is to share bitcoin knowledge, tools, and resources while creating a peer to peer network within the Round Rock community.” Purpose: Grow bitcoin adoption by individuals and small businesses within our local community. Participation encouraged: Stay on topic (bitcoin only) Respect others’ privacy (Chatham house rules) Opportunities: - Free propaganda from bitcoin artists - Bitcoin Book Exchange - Hash The Torch 24 – Altairtech Urlacher Conversion Kit - Blockstream Local - Liquid Workshop Volunteers Ongoing call for speakers & sponsors - Next month: UncleJim21 to discuss CASCDR 

Circular Economy 

Presented by Round Rock Bitcoiners 11 July 2024 | 18:30 CST Allen R. Baca Center Round Rock, Texas Welcome node runner teams! 

WHAT’S A LARP?! ● LIVE ACTION ROLE PLAY ● CHAOS ● LEARNING ● FUN ● BITCOIN NETWORK ● EVERY TABLE = NODE https://www.freepik.com/, @thuynhungle99 

WHAT’S BITCOIN?! ● “A peer-to-peer electronic cash system.” The Bitcoin White Paper https://bitcoin.org/bitcoin.pdf Bitcoin Core https://bitcoin.org/en/bitcoin-core/ 

BITCOIN “A peer-to-peer…” 

BITCOIN “A peer-to-peer, electronic cash system” Bob (receives) Bob (spends) TX A Transaction 2 BTC (to Alice) 7.5 BTC (to Bob’s change address) 10 BTC .5 BTC (to miner) IN OUT OUT OUT UTXO Model (“Unspent Transaction Output”) 

WHAT’S A NODE? ● Computer that runs Bitcoin Core software ○ Follows rules ○ Shares information ○ Keeps a record of transactions 

TIMECHAIN ILLUSTRATION 

● Each team is a node. Dispersed throughout the room to simulate privacy. ● Each node starts by “downloading Bitcoin Core”. I.e. Receive basket of items. This is our physical representation of the Bitcoin core software, made up of many subcomponents. 

DOWNLOAD BITCOIN CORE 

1. “Download” Bitcoin Core Unpack your baskets! Set aside: - the blockchain - a block - the genesis transaction - the UTXO set basket - the secret key card - The BASIC miner - Verification cards 

INSPECT & VERIFY DOWNLOAD 

2. Genesis Block + Transaction *use a block explorer like mempool.space to see the real genesis block! 000000 33 12:34 8500 103554 prev. block hash tx. commitment time target nonce eagle33 

3. Identifying Our Outputs ● Identify our outputs ○ Locate your wallet ○ ID bitcoins which belong to our wallet ● RAISE YOUR HAND IF you have bitcoin locked to your key. eagle33 

4. Verifying the Genesis Block Header Protocol Note: The actual 'transaction commitment' is a Merkle root of all the block's transaction's ids. We don't have a quick and easy way to build a Merkle root. Instead we just use some basic math. eagle33 

5. Calculating the block hash ● Blockhash is shown after all information is entered. Write it above “blockheader” and on back of genesis txn. 000000 33 12:34 8500 103554 prev. block hash tx. commitment time target nonce ON/ CLEAR NEXT PREV. 

VALIDATING + WRITING TXNS. 

6. Validating 1st network transaction APPRO VED eagle33 cat72 

7. Mempools APPROVED cat72 

8. Wallet Balance Check APPRO VED cat72 eagle33 

9. Writing Transactions ● Transaction ID format: “word##” ● Send facilitators (green pubkey, or “lock”) 1 BTC ● Refer to your private key for your node’s color ● Write any transaction fee on back of transaction card *This is real life and we’re playing with some level of trust; please LARP with only the color of your private key. 

10. Adding Transactions To Your Mempool ● Remember to verify transaction; stamp when completed. 

NETWORKING 

11. Sending Network Messages NODE A NODE B NODE C NODE D cat72 dog83 

NODE A NODE B dog83 11. Receiving Network Messages 

11. Receiving Network Messages NODE A NODE B dog83 cat72 3 20 

RUNTIME 

BLOCK BUILDING 

12. Building our 1st block template (1) Coinbase Txn. + (3) Txn.s 7657 8500 prev. block hash tx. commitment time target nonce New Block 

MINING 

● The BASIC will mine instead of verifying when entering a blank nonce. ● After the nonce is found, write down the block hash next to blockheader ● RAISE YOUR HAND as soon as you find the nonce! 13. Mining For Nonces 

● As soon as nonce is found and block hashed, notify all peers with “I HAVE BLOCKS” message w/ block hash(es). 14. Broadcasting & Requesting a Valid Block ● Messages must be acted upon ASAP. Other nodes will send “SEND BLOCKS” message w/ hashes for blocks they need. 

● Create copy of valid block ○ Fill block header (EXCEPT block hash). ○ Fill block ■ Coinbase txn: Make copies to send ■ Other txns: Use Compact Block Protocol (“block txids”) to copy all other txids to ● Send valid blocks to nodes who requested it. 15. Sending Peers Valid Blocks ● cat72 ● dog83 ● balloon18 7657 8500 prev. block hash tx. commitment time nonce target 

● Use the coinbase transaction and Compact Block (“block txids”) to calculate tx commitment. 16. Validating a Block 

● Valid coinbase txn: ○ No inputs ○ Ouput value is ≤50 + sum of txn fees ● Only need to validate txns that are not already in mempool ● If you don’t have listed transaction, you’ll need to request it from the node that sent block. ● If you’re unable to find txn or if it’s already in UTXO set, it’s invalid. Discard block. ● Txns can only spend from UTXOs or from other txns in same block; otherwise, block is invalid. 17. Validating Block Txns 

● Promote all block txns in mempool to UTXO set ● Cross-out any spent inputs in this block, and cross-out corresponding output ● Any new outputs created in block get sent to UTXO set. ● Add block to blockchain. 18. Marking Outputs as Spent 

BUILDING A CHAIN 

● Update with new valid block ○ Discard old block header ○ Use new valid block’s hash for “previous block hash” ○ Update time ○ Pull out txns that were mined in pervious block ○ Update coinbase txn, recalculate txn commitment ○ Attempt to mine updated block 19. Building a chain 

SCORING 

● NODES: Calculate balances of UTXOs that were NOT yours. 20. Scoring 

Thank you for playing! url