The BitVault secure calling is implemented using a private Blockchain. A Bitcoin address from your Bitcoin Vault wallets can be used to make and receive secure encrypted phone calls. When making a secure call, scan the QR code or copy and paste the address of the wallet that you want to make the call to or alternatively select a contact from your contact list. The security features of the BitVault will require you to scan your fingerprint, scan your iris and scan your NFC card before a secure encrypted call can be made. In order to receive a call, you will need to register one of your Bitcoin Vault wallets for secure calling and have to share this address with the person you want to make the secure call with. You can share this with a QR code generated on your BitVault.  When someone calls you, your BitVault will notify you of an incoming call with your BitVault ringing.