BITBLOG

The pace of innovation in the Bitcoin Cash space is amazing. Each week we see new services launch which truly show the strength of the Blockchain. Yesterday Memo launched which is a “Decentralized on-chain social network built on Bitcoin Cash.”

While I think the site is cool IMO the real innovation is the protocol. They’re leveraging OP_RETURN to write data to the blockchain and prefixing it w/ one of 5 prefixes to add sematic meaning. This is a really clever idea and w/ OP_RETURN going from 80 bytes to 220 bytes on the upcoming May 15th Bitcoin Cash upgrade this idea will only get better.

Writing Utility Methods

BITBOX can encode OP_RETURN scripts so I decided to write some helper methods to encode data and prefix it per the MemoBCH protocol. This will accelerate how quickly people can write MemoBCH data to the blockchain

let setName = (name) => {
  let script = [BITBOX.Script.opcodes.OP_RETURN, Buffer.from('6d01', 'hex'), Buffer.from(name)];
  return BITBOX.Script.encode(script)
}

let postMemo = (memo) => {
  let script = [BITBOX.Script.opcodes.OP_RETURN, Buffer.from('6d02', 'hex'), Buffer.from(memo)];
  return BITBOX.Script.encode(script)
}

let like = (txHash) => {
  let script = [BITBOX.Script.opcodes.OP_RETURN, Buffer.from('6d04', 'hex'), Buffer.from(txHash)];
  return BITBOX.Script.encode(script)
}

let follow = (address) => {
  let script = [BITBOX.Script.opcodes.OP_RETURN, Buffer.from('6d06', 'hex'), Buffer.from(address)];
  return BITBOX.Script.encode(script)
}

let unfollow = (address) => {
  let script = [BITBOX.Script.opcodes.OP_RETURN, Buffer.from('6d07', 'hex'), Buffer.from(address)];
  return BITBOX.Script.encode(script)
}

Examples

set name

Prefix: 6d01

Data: satoshi

OP_RETURN: OP_RETURN 6d01 7361746f736869

https://blockchair.com/bitcoin-cash/address/d-863b50cc9d6f20a43cf65bad298bdcca

post memo

Prefix: 6d02

Data: MemoBCH protocol FTW!

OP_RETURN: OP_RETURN 6d02 4d656d6f4243482070726f746f636f6c2046545721

https://blockchair.com/bitcoin-cash/address/d-433a972749493aa5f15ad08b38627e6a

like

Prefix: 6d04

Data: 8966169557a6e65b3a1ab1e4d2caf6c199000f557acb7e0bec6c516de1668f6f

OP_RETURN: OP_RETURN 6d04 38393636313639353537613665363562336131616231653464326361663663313939303030663535376163623765306265633663353136646531363638663666

https://blockchair.com/bitcoin-cash/address/d-614beec4231967e9f3fb145537c01467

follow

Prefix: 6d06

Data: 1F5GrRezwGokQhxmF4fYaBbbNrPPaeBqMm

OP_RETURN: OP_RETURN 6d06 314635477252657a77476f6b5168786d46346659614262624e725050616542714d6d

https://blockchair.com/bitcoin-cash/address/d-9cde8776aae709f5983616f50332c0b8

unfollow

Prefix: 6d07

Data: 1F5GrRezwGokQhxmF4fYaBbbNrPPaeBqMm

OP_RETURN: OP_RETURN 6d07 314635477252657a77476f6b5168786d46346659614262624e725050616542714d6d

https://blockchair.com/bitcoin-cash/address/d-ba9cdd8ad24c41593c36ac5da7ea5c42

Reading Utility Methods

You can also read transaction which follow the MemoBCH protocol using BITBOX. Here’s an example

BITBOX.RawTransactions.getRawTransaction('ade7aa70f0cf99281ff844284a2f6c3d63d1630a3d160bac9ba487d3896ee377').then((result) => {
  BITBOX.RawTransactions.decodeRawTransaction(result).then((result) => {
    let res = JSON.parse(result);
    // need to know index of vout w/ OP_RETURN data
    let asm = res.vout[1].scriptPubKey.asm;
    // OP_RETURN 0x6d01 746573742032
    let fromASM = BITBOX.Script.fromASM(asm);
    let decodedArr = BITBOX.Script.decode(fromASM);

    // prefix
    let memoBCHType = decodedArr[1];
    memoBCHType.toString('hex');
    // 6d01

    // message
    let message = decodedArr[2];
    message.toString('ascii');
    // satoshi

  }, (err) => { console.log(err); });
}, (err) => { console.log(err); });

Summary

Innovation is alive and well on the Bitcoin Cash chain. Weekly we’re seeing new services which push the boundaries of what is possible w/ blockchain technology. BITBOX hopes to enable developers to accelerate how quickly they can do amazing things w/ Bitcoin Cash.