Are wallets provably multisig?

Is it possible to mathematically prove that a specific BTC wallet address is multisig?

No certainty

No, it is not possible to mathematically prove that a specific Bitcoin wallet address is multisig solely based on the address itself. Bitcoin wallet addresses are derived from public keys, and the address alone does not provide any information about whether it is associated with a multisig setup.

Multisig, short for multisignature, is a feature in Bitcoin that requires multiple private keys to authorize a transaction. The information about whether an address is multisig or not is not encoded in the address itself. It is determined by looking at the transaction history and the script used to create the address.

To determine if a specific BTC wallet address is multisig, you would need to analyze the transactions associated with that address. By examining the inputs and outputs of those transactions and analyzing the scripts involved, you can identify if it involves multiple public keys and signatures required for spending.

Therefore, verifying whether an address is multisig or not requires looking beyond the address itself and examining the associated transactions and scripts involved.

Indicators that are "dead giveaways"

In an analysis of Bitcoin transactions to identify whether a specific address is associated with a multisig setup, there are several indicators that can serve as "dead giveaways." Here are some common signs to look for:

1. Script type: Bitcoin uses scripting language to define spending conditions for transactions. Multisig addresses typically involve a specific script type known as Pay-to-Script-Hash (P2SH). P2SH addresses start with the number "3" and are followed by a combination of letters and numbers. So, if the address you are analyzing starts with "3," it could potentially be multisig.

2. Redeem script: When examining the inputs of a transaction, you can look for a redeem script associated with a P2SH address. The redeem script contains the conditions and public keys required to spend the funds. If the redeem script includes multiple public keys, it indicates a multisig address.

3. Signatures: In a multisig transaction, you will find multiple signatures attached to the inputs. Each signature corresponds to a different public key associated with the multisig address.

4. M-of-N setup: Multisig addresses typically involve an M-of-N setup, where M represents the minimum number of signatures required out of N total possible signers to authorize a transaction. If you find evidence of M signatures being used in the transaction, it suggests a multisig address.

5. Analyzing historical transactions: To gain more confidence in identifying a multisig address, you can trace the historical transactions associated with the address. Look for patterns of multiple signatures, involvement of different public keys, and a consistent M-of-N setup across transactions.

Remember that while these indicators can strongly suggest the involvement of multisig, they do not provide absolute proof. Proper analysis and examination of multiple transactions associated with the address are necessary to determine conclusively whether an address is multisig or not.