In this exercise, you'll construct a P2SH (Pay-to-Script-Hash) ScriptPubKey for a given redeem script within a partially constructed transaction.

Here's a breakdown of the partially constructed transaction:

The hexadecimal representation of this transaction is:

10200000002589d75a45b732e3a92da560086568310e33efe5cfb26bcb2685d7ee712af7a3e000000006a-[scriptsig 1]-fdffffff2f8ec63af69ea6d35acb217562bef0467b0354a2dad430a71051041e5cfd0499010000006b-[scriptsig 2]-fdffffff02888a01000000000017-[scriptpubkey]-74658b00000000001976a91468cfed146aced22f422a68015ff8ca180761912a88aceff91700

Exercise

Your task is to complete the constructP2SHScriptPubKey function which creates a P2SH ScriptPubKey for the following redeem script:

    2 3 ADD 5 EQUAL

Instructions:

1. Implement the constructP2SHScriptPubKey function.
2. The function should take the redeem script as input and return the complete P2SH ScriptPubKey.
3. Remember to hash the redeem script and include the necessary opcodes.
4. The provided unit test will check if your implementation is correct.

Choose your preferred language below to start coding:

import CryptoJS from 'crypto-js';

export function constructP2SHScriptPubKey(redeemScript) {
  // TODO: Implement this function
  // Hint: Use CryptoJS.SHA256 and CryptoJS.RIPEMD160 for hashing
}

For this exercise, we've provided the crypto-js (JavaScript) and hashlib (Python) libraries to help with the hashing operations. You should use the relevant library to implement the P2SH ScriptPubKey function.

You can look up the hex characters for each op_code in the Bitcoin Script wiki page.

Inspiration

After completing the exercise, you can check out these testnet transactions to see real P2SH ScriptPubKeys in action:

• Transaction 1

• Transaction 2

These transactions demonstrate how P2SH ScriptPubKeys are used in actual Bitcoin transactions on the testnet.