Bitcoin is often described as programmable money, but its scripting system includes OP_CAT with deliberately strict limits. Those limits help keep Bitcoin predictable and secure, yet they also make some advanced applications difficult to build. One proposed change could expand what Bitcoin Script can do, including OP_CAT, without turning Bitcoin into a general-purpose smart contract … Read more
What if you could create Bitcoin today but make it impossible to spend until a specific time in the future? Bitcoin can do exactly that. A feature called a timelock can restrict when a transaction or particular spending path becomes valid. That might mean: “This Bitcoin cannot be spent until block 900,000.” Or: “Wait 30 … Read more
You open your Bitcoin wallet, enter an amount, and press Send. Behind that simple button, your wallet has to make an important decision: Which Bitcoin should it spend? That might sound strange at first. After all, if your wallet shows a balance of 0.05 BTC, why can’t it simply take 0.01 BTC from that balance … Read more
Your Bitcoin payment is stuck in the mempool. The sender can’t—or doesn’t want to—replace it with a higher-fee transaction. But the recipient still needs the payment to confirm. Is there anything the recipient can do? Sometimes, yes. A technique called CPFP, short for Child Pays for Parent, can help. Instead of replacing the original transaction, … Read more
You send Bitcoin, see the transaction appear as unconfirmed, and then nothing happens. Minutes pass. Then an hour. Maybe the transaction is still sitting in the mempool, waiting for a miner to include it in a block. One common reason is that the transaction paid a fee rate that was too low for the conditions … Read more
When you send Bitcoin, you might assume your wallet simply takes the exact amount you want to send and moves it to another person. Bitcoin does not work quite that way. Bitcoin transactions spend entire UTXOs. If the UTXO you use is worth more than the payment, the remaining Bitcoin has to go somewhere. Usually, … Read more
If you have already read about MuSig2 and PSBTs, you may wonder how the two technologies actually work together. MuSig2 allows multiple Bitcoin participants to cooperate in creating a single Schnorr signature. PSBTs provide a standardized way for wallets and signing devices to exchange transaction information. But there was a problem. A normal PSBT did … Read more
BIPEBitcoin has evolved significantly since the original transaction system was created. The introduction of SegWit changed how transaction data works. Then came Schnorr signatures, Taproot, and Tapscript. These upgrades also created a new challenge: How do different Bitcoin wallets and signing devices exchange all the information needed to create a Taproot transaction? That is where … Read more
Bitcoin multisignature wallets have traditionally required multiple public keys and multiple signatures to spend coins. That works, but Bitcoin’s Taproot upgrade opened the door to a more compact approach. BIP-327 introduces MuSig2, a multisignature scheme that allows multiple signers to collaboratively create a single Schnorr signature under one aggregate public key. Instead of putting several … Read more
Bitcoin has a scripting system that determines the conditions a user must satisfy before they can spend their coins. For years, Bitcoin Script provided the foundation for everything from simple payments to more advanced arrangements such as multisignature wallets and time-locked transactions. However, the introduction of Taproot changed how Bitcoin scripts could work. One important … Read more