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ブロックチェーン 2.0 / Blockchains 2.0

Kenji Saito
December 07, 2017

ブロックチェーン 2.0 / Blockchains 2.0

2017年12月7日(木)、ブロックチェーンアカデミー「ブロックチェーン基盤技術 ブロックチェーン 2.0」にて使用したスライドです

Kenji Saito

December 07, 2017
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  1. ( ) SFC ( ) CSO (Chief Science Officer) 1993

    M.Eng ( ) 2006 ( ) SFC 17 P2P 2011 → ( ) 2.0 — — 2017-09-07 – p.2/41
  2. 2.0 1. 2. Segregated Witness 3. 4. Proof of Stake

    ( ) 5. 6. 2.0 — — 2017-09-07 – p.4/41
  3. ID ID (asset ID) 1. 2. 3. 160 = ID

    ( ) 4. base58check ‘A’ ( = 23) (asset quantity) BTC 2.0 — — 2017-09-07 – p.9/41
  4. OP_RETURN PUSH 0x4f41 (‘OA’) = 2 0x0100 2 1∼9 LEB128

    1∼9 2.0 — — 2017-09-07 – p.10/41
  5. Merkle Tree (Bitcoin) Digest = double SHA-256 value Existence of

    a TX can be verified if a relevant subtree is provided 2.0 — — 2017-09-07 – p.15/41
  6. (1) P2WPKH (version 0) (pay-to-(witnessed)-public-key-hash) witness ( ): < >

    < > scriptSig ( ): scriptPubKey ( ) 0 <20-byte > 20-byte < > < > CHECKSIG 2.0 — — 2017-09-07 – p.16/41
  7. (2) P2WSH (version 0) (pay-to-(witnessed)-script-hash) witness: < 1 > <1

    < 1 > < 2 > 2 CHECKMULTISIG> scriptSig: scriptPubKey 0 <32-byte > 32-byte 1-out-of-2 2.0 — — 2017-09-07 – p.17/41
  8. SegWit 2016 100 SegWit (95% ) . . . 2017

    8 24 2.0 — — 2017-09-07 – p.19/41
  9. BIP (Bitcoin Improvement Proposal) ex. BIP 1 : BIP Purposes

    and Guidelines https://github.com/bitcoin/bips/blob/master/bip-0001.mediawiki ex. BIP 9 : Version bits with timeout and delay ex. BIP 141 : Segregated Witness (Consensus layer) TCP/IP RFC XMPP XEP 2.0 — — 2017-09-07 – p.21/41
  10. Block Header Data Structure Field Description Size (bytes) Version 4

    Digest Double SHA-256 value 32 Merkle root Double SHA-256 value 32 Time Seconds (since 1970-01-01T00:00 UTC) 4 Target Compressed format 4 Nonce Appropriate value 4 Merkle root is the digest of all TXs 2.0 — — 2017-09-07 – p.22/41
  11. Proof of Stake ( ) ( ) 2.0 — —

    2017-09-07 – p.25/41
  12. Proof of Stake Hn (PD + id + t +

    . . .) ≤ 2n × balance d H n : n (ex. SHA-256 (n = 256)) PD : id : (ex. ) t : (ex. UNIX ( )) balance : d : (ex. ) PoW 2.0 — — 2017-09-07 – p.26/41
  13. Proof of Stake 3 1. 2. “Nothing at Stake” 3.

    51% 2.0 — — 2017-09-07 – p.27/41
  14. → ⇒ A. Back, et. al., “Enabling Blockchain Innovations with

    Pegged Sidechains”, 2014 2.0 — — 2017-09-07 – p.36/41