Quorum how to decode result returned by eth_getQuorumPayload api?

Question

I've read the post How to get decrypted transaction data in quorum?

I followed the api document and got the result by calling eth_getQuorumPayload

curl -H "Content-Type: application/json" -X POST http://127.0.0.1:22000 --data '{"jsonrpc":"2.0", "method":"eth_getQuorumPayload", "params":["0x0904cbd975e6fd2444c6f029e951be0af68cf60af603070a561b46d683d754a08a0986c842b7d9468cc2be05c9e7afcab972ea3034ac48aaebb032629e6970cf"], "id":67}'

Result:

{"jsonrpc":"2.0","id":67,"result":"0x60fe47b10000000000000000000000000000000000000000000000000000000000000010"}

How to decode "0x60fe47b10000000000000000000000000000000000000000000000000000000000000010" into a readable string? I set the 'storedData' in private contract to 16, so I got '0x10' in the last byte in result, is it right? What does the first few bytes '0x60fe47b1' mean?

Answer 1

When you perform a call like contract.set(0x10, ....), this is encoded into a payload like "0x60fe47b10000000000000000000000000000000000000000000000000000000000000010". Where "0x60fe47b1" is the keccak256 encoded value of the method signature, and the rest of the data is the passed parameters (I can't recall atm how the parameters are encoded).

So, when you call getQuorumPayload(), it is returning that payload from the transaction manager.

There's a good article on the encoding here: How to decipher a smart contract method call