Calculate the public key of your Opendime without revealing its private key!
Navigate to your Opendime and find the file advanced/verify2.txt inside. Paste contents below.
Now you can use your favorite wallet or coinb.in to create a multisig address!
How it works: Bitcoin Signed Messages enable verification by allowing anyone with the message and signature to calculate the public key corresponding to the private key that signed the message.
Use at own risk. Don't trust, verify.