Agenda

• How Ordinals NFTs Work
• Where and How to inscribe (Inscriptions)
• BRC20
• 其他衍生協議
• 總結

Ordinals

• 總共有 21,000,000 顆BTC
• 1顆 BTC 可分成最小單位 100,000,000 Satoshi (聰 SAT)
• Ordinal Theory Rarity
  – common: Any sat that is not the first sat of its block
  – uncommon: The first sat of each block
  – rare: The first sat of each difficulty adjustment period
  – epic: The first sat of each halving epoch
  – legendary: The first sat of each cycle (6 halving)
  – mythic: The first sat of the genesis block

Ref: Ordinal Theory Handbook

UTXO

UTXO Coinbase

• Coinbase Transaction:
  – special tx
  – no input and one or more outputs
  – rewards + gas fee

Bitcoin Exploer

Where to inscribe

• 從2017年 SegWit 升級 (BIP141) 後，Witness data 從交易數據中分離出來
• SegWit升級後，Transaction size (body + witness) 最大是 4MB
• 錢包地址開頭為 bc1q

How to inscribe

• 從2021年 Taproot 升級後 (BIP342)，可以在bitcoin上寫智能合約(tapscript)
• 錢包地址開頭為 bc1p

OP_FALSE
OP_IF
  OP_PUSH "ord"
  OP_1
  OP_PUSH "text/plain;charset=utf-8"
  OP_0
  OP_PUSH "Hello, world!"
OP_ENDIF

Ref: Ordinal Theory Handbook

Witness brc20 example

• $ORDI [deploy]
  – blockchain explorer
  – unisat
• $ORDI [mint]
  – blockchain explorer
  – ordinals

Ordinals Dune 統計

Ref: https://dune.com/cryptokoryo/brc20

BRC-20 起源

brc-20-experiment

BRC-20 operation

• deploy, mint, transfer

ORC-20

https://docs.orc20.org/

ORC-20

BRC-21

BRC-21 Token Standard

總結

• 在 bitcoin 的 witness 寫 inscription 而創造 brc-20 token
• bitcoin 的智能合約 tapscript 受限，無法使用合約交互得知各個地址brc-20目前狀態
• 依賴於中心化的 indexer 解析 inscription 數據而拆分出brc-20狀態
• 因 bitcoin 網路出塊時間約10分鐘，而brc-20的Transfer需兩步驟，導致UX很差

Reference

• https://medium.portto.com/dive-into-how-bitcoin-ordinals-nfts-work-ca5634da73d
• https://domo-2.gitbook.io/brc-20-experiment/
• https://unisat.io/
• https://thebitcoinmanual.com/articles/btc-ordinal-explorer/

Q & A

Bitcoin Unlock / Locking Script

Bitcoin address type

• Legacy (P2PKH) 開頭為 1
  – 傳統地址
  – 15e15hWo6CShMgbAfo8c2Ykj4C6BLq6Not

• P2SH 開頭為 3
  – 支援多簽
  – 35PBEaofpUeH8VnnNSorM1QZsadrZoQp4N

Bitcoin address type

• SegWit、bech32 (P2WPKH) 開頭為 bc1q
  – 交易跟簽名分離
  – 允許 3MB 簽名數據和 1MB 的交易數據
  – bc1q42lja79elem0anu8q8s3h2n687re9jax556pcc

• Taproot (P2TP) 開頭為 bc1p
  – Schnorr簽章 (BIP340)
  – Taproot (BIP341)
  – Tapscript (BIP342)
  – bc1pmzfrwwndsqmk5yh69yjr5lfgfg4ev8c0tsc06e

Bitcoin address type

Reference: https://dune.com/queries/1883950/3103481

Bitcoin UTXO

Example:

• 2 input => 1 output
• 1 input => n output

Ref: https://ithelp.ithome.com.tw/articles/10216976