Here's how I would like to confirm that my cosigners are competent.
Step 1: Prepare a Unique Message
📝 Prepare a unique and freshly generated message that you will provide to your cosigner.
Step 2: Specify Derivation Path
🔑 Define the derivation path for your cosigner.
Step 3: Request Cosigner's Cryptographic Signature
🔒 Share the message, the derivation path and the participating xpub with your cosigner and request a cryptographic signature from them.
Step 4: Cosigner's Action
🖋️ Your cosigner signs the message you provide, using a key derived from the xprv partner to their xpub.
Step 5: Calculate Public Key
🔍 Calculate the public key by applying the specified derivation path to their xpub.
Step 6: Verify Signature
🛡️ Verify the signature's validity using the derived public key.
Step 7: Establish Trust
🤝 If the signature is valid, you can trust that your cosigner maintains control of their key.