Mobile Key

The lowest tier of Casa storage is a single-key storage system kept on the client’s mobile device

Target Use and Audience

The Mobile Key storage system is designed for beginning clients that have small amounts of bitcoin (<$1k) that do not need more complex and secure storage systems

System Details

The Mobile Key storage system is a 1-of-1 system with the single key kept on a client’s phone.

Features provided with the Mobile Key system:

  • Mobile Key Backup - An encrypted copy of the mobile key is kept in the cloud storage offered by the client’s mobile provider (iCloud or Google Drive). The decryption key is kept by Casa. This allows a client to recover their mobile key if it is lost, for example by dropping their phone off a boat. At the same time, neither Casa nor the mobile provider have access to the key.

Threat Mitigation

  • Data and Credential Loss - The mobile key backup provide additional layers of safety against accidental loss.

  • Credential Theft - The mobile key is guarded by two sets of credentials (mobile login + Casa login) or two biometric/PIN gates (the phone lock screen and the Keymaster app lock screen).

  • Stolen Phone Attack - Use of the mobile key in the Keymaster app is protected by biometric identification or a PIN and the phone manufacturer’s locking system.

  • Official Seizure - Casa does not have access to the client’s encrypted key backup, and so cannot be forced to turn over client’s funds. However, an authority could force both Casa and the mobile provider (Apple and Google) to turn over information (the decryption key stored with Casa and the encrypted backup stored with the mobile provider) that in combination could be used to access client funds.