What are the privacy and security implications when sharing a vault?

Your vault partner can see various information when you share a vault. There are different privacy implications depending on how you use your shared vault.

Sharing a vault using a shared key from a connection partner: 

By default, the vault will not be automatically shared with them until you edit its permissions. This is known as a blinded vault. If you request that your partner sign a transaction, the vault will remain blinded on the Unchained platform. However, in order for their device to sign the transaction, some information must be shared with the connection partner's device. 

Information disclosed when requesting a signature from your vault partner:

  • Transaction amount
  • Destination address(es)
  • PSBT with all three extended public keys
    • The vault permissions will remain the same on the Unchained platform. However, a technical individual could theoretically use this information to derive your wallet configuration file. 

To maintain maximum privacy with your connection partner, you can have Unchained provide the second signature when withdrawing bitcoin from your vault. 

Sharing a vault where your partner does not have a key in the vault:

Note: Sharing vault access with someone without using shared keys is an exclusive feature for Unchained Signature clients. Contact us if you're interested in this feature.

If you share full vault details, your connection partner will have full-view access to all of your vault's details, including the wallet configuration file and transaction history. When you stop sharing a connection vault that has had full vault details shared, the vault will no longer be visible on the Unchained platform. However, the connection partner may have downloaded the wallet configuration file.