Most people think Ethereum invented smart contracts.
But let’s rewind the blockchain history a bit...
In the beginning, there was Bitcoin Script from Day 1.
Bitcoin Script – a simple, stack-based, non-Turing-complete language.
It can’t do loops or fancy DeFi yield farms, but here’s what it could do long before ETH was a whitepaper:
- Multisig txns
- Timelocks (CLTV/CSV)
- Escrow Logic
- Deadman Switches
- Hash Time-Locked Contracts (HTLCs) – the basis of the Lightning Network (happens when you pay regtest or testnet from mainnet)
- Atomic Swaps (direct exchange of one cryptocurrency for another without the need for a trusted third party - a huge feat for a beginner)
All of these are types of smart contracts.
Not flashy but secure.
But Why Is Bitcoin Script So “Dumb”?
Because dumb is not weak (duh)
Dumb = secure, auditable, hard to exploit (duh)
Bitcoin’s design deliberately avoids complexity. Why?
- No infinite loops = less attack surface
- No memory overflow risks
- Easy for full nodes to verify in a deterministic way.
- Hard for devs to write bugs that lose billions 😂
Nonetheless, upgrades Have Made Bitcoin Even Smarter
SegWit enabled more flexible scripts while Taproot (2021) combines signatures, enables MuSig, and hides smart contract conditions
Miniscript is a new language to write and analyze complex Bitcoin scripts securely
Here’s a side-by-side hand-on comparison of a Bitcoin Script contract and a Solidity contract that perform a similar function: a simple 2-of-2 multisig wallet.
Goal: Funds can only be spent if 2 out of 2 parties sign the transaction.
Bitcoin Script (P2SH 2-of-2 Multisig)
# Redeem Script (before being hashed into P2SH address)
OP_2
<PubKeyA>
<PubKeyB>
OP_2
OP_CHECKMULTISIG
OP_2 - Require 2 signatures
<PubKeyA>, <PubKeyB> - The two public keys
OP_CHECKMULTISIG - Checks that 2 valid signatures are provided
To spend:<sigA> <sigB> <redeemScript>
Simple
On-chain efficiency via P2SH
No state, loops, or advanced logic
On the other hand, while releasing my meme tokens on Polygon, I had to screw up this hell of a code until I realised Bitcoin was easier. This is just a sample tho.
Solidity Smart Contract (Ethereum Equivalent)
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
contract MultiSigWallet {
address public owner1;
address public owner2;
constructor(address _owner1, address _owner2) {
owner1 = _owner1;
owner2 = _owner2;
}
function transfer(address payable to, uint256 amount, bytes memory sig1, bytes memory sig2) public {
require(msg.sender == owner1 || msg.sender == owner2, "Not authorized");
// Pseudocode for signature verification
require(verify(sig1, owner1), "Invalid sig1");
require(verify(sig2, owner2), "Invalid sig2");
to.transfer(amount);
}
function verify(bytes memory sig, address signer) internal pure returns (bool) {
// Signature verification logic (simplified)
return true; // placeholder
}
receive() external payable {}
}
🤦♂️ More attack surface, costlier gas, unnecessarily complex