We believe our service should respect the built-in sovereignty of Bitcoin. In addition to providing a self-custody service, we developed a software architecture that relies on no third parties to provide the service and its software. Moreover, our software development process is not constrained by third-party platforms (e.g. Apple, Google) and does not use third parties to host client data.
Our Self-Custody Account does not rely on third-party cloud hosting platforms such as Amazon Web Services. All services are hosted on our own servers in a state-of-the-art data center in the heart of Switzerland.
The building that houses the data center many meters below ground is owned by one of Switzerland’s largest network companies. The facility is capable of withstanding all kinds of military and civilian threats.
Access to the facility is very strictly controlled. Only designated and police-certified employees of the operating company have access to certain areas. Each operation is conducted on the basis of the four-eyes principle, a requirement that specifies that two individuals must approve an action before it can be taken. All locations are under 24/7 video surveillance and equipped with a sophisticated fire alarm system.
The data center also has biometric access control, equal-height turnstiles, video surveillance, emergency power systems, fail-safe air conditioning and a fully redundant Internet connection.
Storage services providing a cloud backup on platforms like iCloud do not guarantee End-to-End encryption. This results in companies like Apple being able to access your backup or provide information to governments or institutions.
In the case of Self-Custody, the backup of your Private Key is hosted in our own servers using AES-GCM 256-bit military-grade encryption. With this we guarantee that no one but you can access your data.
In addition, we follow strict Privacy and Security standards based on Swiss law.
Self-Custody is a web-only company. This means that we purposefully refrain from providing a smartphone app, as we believe that an app would compromise the security of your Bitcoin.
“Every app initially poses an additional security risk, even if it is a legitimate offer” - German Federal Office for Information Security.
App users have to trust the manufacturer of their device and its operating system (e.g. Apple or Google) as well as the publishers of the app. Users must also be able to trust the third party over which data is exchanged before downloading apps and saving or sending data. Numbrs does not want to expose its clients to this risk and therefore does not offer a smartphone app.
The entity that owns the app store (e.g. Apple or Google) will know that you have a particular app installed, as will your mobile phone service provider. These entities may also collect statistics around use. To guarantee the ultimate level of privacy, we have decided not to offer a smartphone app to our clients.