Dialysis machine, a fluid preparation device, and methods for establishing secure communication between a dialysis machine and a fluid preparation device

A dialysis system comprising:

• a fluid preparation device having a first short-range communication interface a first memory storing a passkey, and a shared key generated using the passkey and at least one predetermined criterion;
• and
• a dialysis machine configured to receive fluid from the fluid preparation device, the dialysis machine including a second short-range communication interface, a second memory, and a control unit, wherein the control unit of the dialysis machine is configured to cause the dialysis machine to establish, using the second short-range communication interface, a short-range wireless connection between the dialysis machine and the fluid preparation device by:
• after being powered on, determining whether a bonding table exists in the second memory or whether a bonding table is empty,
• when the bonding table does not exist in the second memory or is empty, causing a user interface of the dialysis machine to display a prompt to enter a passkey associated with the fluid preparation device,
• receiving, via in the user interface, the passkey,
• using the passkey to pair the dialysis machine with the fluid preparation device,
• creating a new bonding table or writing to an empty bonding table in the second memory using the passkey,
• generating the shared key using the passkey and the at least one predetermined criterion,
• storing the shared key to a key table in the second memory,
• using the shared key to authenticate with the fluid preparation device, and
• when authentication with the fluid preparation device is successful, enabling data communication using the short-range wireless connection with the fluid preparation device.