Multisig Wallet Setup

Multiple Private Keys and Seeds: You need multiple seed phrases (12-24 words) for each private key involved in your multisig setup. These must be kept secret and never stored digitally on an internet-connected device. "Never upload your private 12-24 word mnemonics to the cloud or even type them into your PC/phone password manager or email or photo roll."

XPUBs (Extended Public Keys): Collect the extended public keys for all co-signers. These reveal your wallet balance but not your funds. "You have to backup : All of your private 12-24 words mnemonics AND All of your cosigners' XPUBs"

Wallet Descriptor/Configuration File: This file contains essential information like derivation paths, fingerprints, and all co-signers' XPUBs, allowing you to rebuild your wallet even if your software is wiped. "Ideally your multisig wallet descriptor (wallets like Specter can export this as a .PDF for you)"

Test Your Setup Thoroughly: Before committing significant funds, create and test your multisig setup by sending small transactions in and out. "It's important when your creating a setup that you thoroughly test it."

Geographical Distribution of Keys: Store your private keys and backups in different physical locations to prevent a single point of failure. "So each private key is not going to be located in the same building as another private key in this set up."

Multivendor Hardware Wallets: Use hardware wallets from different manufacturers for your keys to mitigate risks from vulnerabilities in a single vendor's product. "Multisig using wallets from different vendors solves this."

Complexity: Multisig can be more complex to manage than single-signature wallets, increasing the risk of user error. "Multisig is great until you realize your biggest attack vector is your own memory and backup organization."

All Public Keys are Essential: To spend from an m-of-n multisig wallet, you need 'm' private keys and all 'n' public keys. "Biggest pitfall of multisig, to spend from an m of n wallet, you need m private keys and all n public keys (plus a passphrase, if you set one up)."

Passphrases with Multisig: While passphrases add another layer of security, combining them with a 2-of-3 multisig setup might introduce unnecessary complexity. "Personally I wouldn't use a passphrase in addition to a 2-3 multisig. That is added complexity for little benefit."