Banking on a Blockchain
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This document outlines RBS's approach to blockchain innovation, particularly in developing a digital wallet using Hyperledger Fabric. It details various functionalities required for the digital wallet, challenges encountered in blockchain implementation, and insights gained from collaborations within the R3 group. The document also raises questions about the future of banking and blockchain integration.
![Extending the contract for multiple
transfers - complex types!
go - chain code
type Transfer struct {
From string `json:"from"`
To string `json:"to"`
Amount float64 `json:"amount"`
}
type DigitalWalletBlockChainTransaction struct {
Transfers []Transfer `json:"transfers"`
RequestedAt string `json:"requestedAt"`
Reference string `json:"reference"`
Description string `json:"description"`
Action string `json:"action"` // "action": "deposit | reserve | unreserve",
Notes []string `json:"notes"` // "for reserve, the from is 'userid ' and to is 'userid-reserve'",
}](https://image.slidesharecdn.com/bankingonablockchain-160808154323/85/Banking-on-a-Blockchain-8-320.jpg)
![We can easily send complex types into
the fabric from javascript
//Build the payload
var transferPayload ={ "transfers":[
{"from": "billy", "to": "greg", "amount": 1000.0 },
{"from": "billy", "to": "mark", "amount": 1000.0 }
],
"requestedAt": "2016-01-03T10:00:00.000Z",
"reference": "dispersals",
"description": “billy sends greg and mark some cash",
"action": "transfer",
"notes" : [“enables rollback of whole transaction on fail" ]
};
//Function to call it
function transfer(transferpayload){
var request = require('request');
request({
url: blockchainServer+'/devops/invoke', //URL to hit
method: 'POST',
json: {
"chaincodeSpec":{ "type": "GOLANG", "chaincodeID":{ "name":chainCodeStatic,
},
"ctorMsg": {
"function":"transfer",
"args":[transferpayload]
}
etc….](https://image.slidesharecdn.com/bankingonablockchain-160808154323/85/Banking-on-a-Blockchain-9-320.jpg)
![Querying account balance is then quite
easy
function queryit(account){
var request = require('request');
//Lets configure and request
request({
url: blockchainServer+'/devops/query', //URL to hit
method: 'POST',
//Lets post the following key/values as form
json: {
"chaincodeSpec":{
"type": "GOLANG",
"chaincodeID":{
"name":chainCodeStatic,
},
"ctorMsg": {
"function":"query",
"args":[account]
}
}
}](https://image.slidesharecdn.com/bankingonablockchain-160808154323/85/Banking-on-a-Blockchain-10-320.jpg)
Banking on a Blockchain
- 1. Banking on a Blockchain Mark Simpson, Distinguished Engineer Innovation Engineering @ RBS
- 2. Key points: How RBS is approaching Research and Innovation What we have looked at in the distributed ledger space Example - building a digital wallet on Hyperledger Fabric What we’ve learnt about Hyperledger and other DLs. The challenges we face as a bank and as blockchain developers Some thoughts for the future
- 3. What is a code spike? Identity a disruptive technology Find a specific use case Find some experienced engineers and give them four days Build an MVP or fail fast
- 4. What distributed ledger technology have we looked at so far?
- 5. Could we build a digital wallet on blockchain?
- 6. Requirements for building a digital wallet Move money from ‘real’ account to wallet Make multiple transfers between accounts in wallet Make payments out of the wallet to payment systems Query wallet balances Detect transaction errors Query history of transactions Obfuscate fields in transactions for certain users
- 7. Where to start? use the example !! https://github.com/hyperledger/fabric/tree/master/exa mples/chaincode/chaintool/example02/src/chaincode
- 8. Extending the contract for multiple transfers - complex types! go - chain code type Transfer struct { From string `json:"from"` To string `json:"to"` Amount float64 `json:"amount"` } type DigitalWalletBlockChainTransaction struct { Transfers []Transfer `json:"transfers"` RequestedAt string `json:"requestedAt"` Reference string `json:"reference"` Description string `json:"description"` Action string `json:"action"` // "action": "deposit | reserve | unreserve", Notes []string `json:"notes"` // "for reserve, the from is 'userid ' and to is 'userid-reserve'", }
- 9. We can easily send complex types into the fabric from javascript //Build the payload var transferPayload ={ "transfers":[ {"from": "billy", "to": "greg", "amount": 1000.0 }, {"from": "billy", "to": "mark", "amount": 1000.0 } ], "requestedAt": "2016-01-03T10:00:00.000Z", "reference": "dispersals", "description": “billy sends greg and mark some cash", "action": "transfer", "notes" : [“enables rollback of whole transaction on fail" ] }; //Function to call it function transfer(transferpayload){ var request = require('request'); request({ url: blockchainServer+'/devops/invoke', //URL to hit method: 'POST', json: { "chaincodeSpec":{ "type": "GOLANG", "chaincodeID":{ "name":chainCodeStatic, }, "ctorMsg": { "function":"transfer", "args":[transferpayload] } etc….
- 10. Querying account balance is then quite easy function queryit(account){ var request = require('request'); //Lets configure and request request({ url: blockchainServer+'/devops/query', //URL to hit method: 'POST', //Lets post the following key/values as form json: { "chaincodeSpec":{ "type": "GOLANG", "chaincodeID":{ "name":chainCodeStatic, }, "ctorMsg": { "function":"query", "args":[account] } } }
- 11. What about Errors ?? You get an error if you send a bad payload or call an invalid chaincode (back in February) Errors did not propagate out of chain code even if you returned an error. There was no error code on the transaction in the block But, state is rolled back if your chain code returns error. You can now detect transaction errors using the following code: https://github.com/hyperledger/fabric/tree/master/example s/events/block-listener
- 12. How did we do against our requirements? Move ‘money’ from real account to wallet √ Make multiple transfers between accounts in wallet √ Make payments out of the wallet to payment systems √ Query wallet balances √ Detect transaction errors √ (nearly) Query history of transactions X Obfuscate some fields in transactions from certain users X
- 13. Transaction history - single version of the truth ? https://github.com/hyperledger/fabric/wiki/Next- Ledger-Architecture-Proposal#pointintime
- 14. What did we learn? Writing and calling contracts is straight forward. Asynchronicity is a challenge. Maintaining a single version of the truth is a battle. Tooling is work in progress. Devops - interesting….
- 15. <devops?>
- 16. Working with R3 ‘ There is only so much fun you can have with blockchain on your own’ - Richard Crook - head of innovation Engineering. We are active members of the R3 group. R3 gives us the ability to openly collaborate with other banks under non disclosure agreements.
- 17. key challenges collaborating with each other security - data at rest scalability bad press / building understanding contract safety integrating ‘safely’ with the existing banking systems (http://bankofapis.com) managing change usability / consumerability
- 18. Some thoughts for the future When will we see banks use ledgers in production? Will contracts be used as legal language? How de-centralised could the banking system become? Why don’t google, facebook, amazon appear to be interested in blockchain? Does blockchain give people the opportunity to secure their own personal data? Could a blockchain be run entirely on mobile devices?
- 19. QUESTIONS ?