This document provides an overview of FabToken, which enables token management in Hyperledger Fabric version 2.0. It describes the Unspent Transaction Output (UTXO) model used, how tokens are issued, transferred, and redeemed through transactions on the ledger, and the roles of different components like orderers and peers. It also outlines the token lifecycle and provides code samples for issuing, listing, transferring, and redeeming tokens using the Fabric SDK.

1. Hyperledger Fabric – v2.0
Alpha
FabToken Overview & Hands-On
Lab
Hyperledger Korea User Group

2. 2

3. 엔터프라이즈 블록체인 - Token
3
• R3 Corda – Tokens SDK
• JP Morgan Quorum – JPM Coin
- https://www.jpmorgan.com/global/news/digital-coin-payments
• Hyperledger Fabric v2 – FabToken
- Token Management Enablement in Hyperledger Fabric
 http://bit.ly/2KvVKb4
- Token (base support) - Support Issue, Transfer, and Redeem Token Operations
 https://jira.hyperledger.org/browse/FAB-11144
- Using FabToken
 https://hyperledger-fabric.readthedocs.io/en/latest/token/FabToken.html

4. FabToken
4
• Hyperledger Fabric v2.0
- https://github.com/hyperledger/fabric/tree/master/token
• Token Management System
• Unspent Transaction Output (UTXO) 모델
• 합의, 검증을 위해 Orderer, Peer 사용
• 토큰 생성, 관리를 위해 체인코드를 사용하지 않음.(Endorsement Policy X)
• s송/수신자 식별 – MSP
• Token Lifecycle: Issue, Transfer, Redeem, List

5. Unspent Transaction Output (UTXO)
5출처 - https://codechain.readthedocs.io/en/latest/transactions.html

6. Hyperledger Fabric – UTXO
6
• 패브릭에서는 상태(State)는 Key-Value 형태로 저장
Key : Namespace + TokenPrefix + Owner + TransactionId + Index
Value: Quantity
• Unspent Transaction(Output)은 Ledger(State DB)에 저장되고
Spent Transaction(Input)은 Ledger(State DB)에서 삭제됨.

7. Hyperledger Fabric – UTXO Transaction
7
Org1
100
IN OUT
Org1
100
IN OUT
Org1
50
Org2
50
Tx #1 Tx #2
{Org1-Tx#1, 100}
Issue to Org1(100) Transfer Org1 to Org2(50)
{Org1-Tx#2, 50}
{Org2-Tx#2-1, 50}
{Org1-Tx#1, 100}
Redeem from Org2(20)
Tx #3
Org2
50
IN OUT
Org2
30
20
{Org1-Tx#1, 100}
{Org1-Tx#2, 50}
{Org2-Tx#2-1, 50}
{Org2-Tx#3, 30}
{Tx#3-1, 20}

8. Token Transaction Flow
8
Client Prover Peer
① Request
(Issue,Transfer,Redeem)
② TokenTransaction
③ Envelope
④ Block
Peer
(Committer)
Validation(VSCC)
Commit(Simulation)

9. Prover Peer
9
• 연산(computation) 실행…
• 비밀정보 유지…
• 트랜잭션 상태, 토큰 몰록 질의 대응…
• 토큰 발행 및 전송 시 검증
- TokenTransaction 생성

10. Token Lifecycle
10
• Issue
• List
• Transfer
• Reedem

11. Token Lifecycle – issue (계속)
11
• 채널 내 허가 받은 MSP에 의해 토큰 생성
- IssuingPolicy : v2.0 alpha 버전에서는 ANY로 설정됨.
• 속성
- Owner: MSP
- Type: 토큰 이름. 예> FabCoin, HLKUGCoin,…
- Quantity

12. Token Lifecycle - issue
12
• SDK (node.js)
const tokenclient = client.newTokenClient(mychannel);
const txId = client.newTransactionID();
const param = {
owner: user1.getIdentity().serialize(),
type: 'USD',
quantity: '500',
};
const issueRequest = {
params: [param],
txId: txId,
};
const result = await tokenClient.issue(issueRequest);

13. Token Lifecycle – list (계속)
13
• Unspent 토큰에 대해 질의
- 권한: 토큰 소유자 MSP
• 질의 결과 값
- TokenID: 트랜잭션 ID, 인덱스
- Type: 토큰 이름. 예> FabCoin, HLKUGCoin,…
- Quantity

14. Token Lifecycle - list
14
• SDK (node.js)
const user1Tokenclient = client1.newTokenClient(mychannel);
const mytokens = await user1TokenClient.list();
for (const token of tokens) {
// get token.id, token.type, and token.quantity
// token.id will be used for transfer and redeem
}

15. Token Lifecycle – transfer (계속)
15
• 토크 전달, 토큰 소비
- 권한: 토큰 ID의 소유자(MSP)
• 파라미터
- Token ID: 토큰 ID
- Quantity
- Recipient: 수신자(MSP)

16. Token Lifecycle - transfer
16
• SDK (node.js)
const txId = client1.newTransactionID();
const param = {
owner: user2.getIdentity().serialize(),
quantity: '300',
};
// create the request for transfer
const transferRequest = {
tokenIds: [tokenid1],
params: [param],
txId: txId,
};
const mytokens = await user1TokenClient.transfer(transferRequest);

17. Token Lifecycle – redeem (계속)
17
• 비즈니스 네트워크(채널)에서 asset(token) 제거
- 권한: 토큰 ID의 소유자(MSP)
- Reedm된 토큰은 transfer/change되지 않음.
• 파라미터
- Token ID: 토큰 ID
- Quantity

18. Token Lifecycle - redeem
18
• SDK (node.js)
const user2Tokenclient = client2.newTokenClient(mychannel);
const txId = client2.newTransactionID();
const param = {
quantity: '100',
};
const redeemRequest = {
tokenIds: [tokenid2],
params: [param],
txId: txId,
};
const result = await user2TokenClient.redeem(redeemRequest);

19. 핸즈온 랩 자료
19
http://bit.ly/hlkug_handson190
6

20. BYFN(Building Your First Network)
20
Peer Peer
Peer PeerOrderer
Org1
Org2peer0.org1.example.com
peer1.org1.example.com
peer0.org2.example.comorderer.example.com
fabric_byfn
peer1.org2.example.com

21. Future features
21
• non-fungible tokens
- Non fungible tokens cannot be merged or divided.
• chaincode interoperability
- allows tokens to be issued, transferred, and redeemed by chaincode

22. 22
감사합니다.