A medical device with limited computational capability, the medical device comprising: medical hardware configured to perform a medical function on a human or animal body; a first register to store a static, substantially unique identifier of the medical device; a second register to store a static encryption key; an interface to receive and transmit data over a short-range communication link; and processing hardware communicatively coupled to the first register, the second register, the interface and the medical hardware, the processing hardware configured to: (i) apply the static encryption key to the identifier of the medical device to generate an encrypted identifier of the medical device, (ii) transmit, via the interface, the encrypted identifier of the medical device to another device, (iii) receive, via the interface, an encrypted identifier of the other device, (iv) decrypt the encrypted identifier of the other device using the static encryption key to determine an identifier of the other device, (v) generate a dynamic encryption key using the identifier of the medical device and the identifier of the other device, and (vi) apply the dynamic encryption key to medical data transmitted between the medical device and the other device, wherein the medical data is related to operation of the medical hardware. medical hardware configured to perform a medical function on a human or animal body; a first register to store a static, substantially unique identifier of the medical device; a second register to store a static encryption key; an interface to receive and transmit data over a short-range communication link; and processing hardware communicatively coupled to the first register, the second register, the interface and the medical hardware, the processing hardware configured to: (i) apply the static encryption key to the identifier of the medical device to generate an encrypted identifier of the medical device, (ii) transmit, via the interface, the encrypted identifier of the medical device to another device, (iii) receive, via the interface, an encrypted identifier of the other device, (iv) decrypt the encrypted identifier of the other device using the static encryption key to determine an identifier of the other device, (v) generate a dynamic encryption key using the identifier of the medical device and the identifier of the other device, and (vi) apply the dynamic encryption key to medical data transmitted between the medical device and the other device, wherein the medical data is related to operation of the medical hardware. (i) apply the static encryption key to the identifier of the medical device to generate an encrypted identifier of the medical device, (ii) transmit, via the interface, the encrypted identifier of the medical device to another device, (iii) receive, via the interface, an encrypted identifier of the other device, (iv) decrypt the encrypted identifier of the other device using the static encryption key to determine an identifier of the other device, (v) generate a dynamic encryption key using the identifier of the medical device and the identifier of the other device, and (vi) apply the dynamic encryption key to medical data transmitted between the medical device and the other device, wherein the medical data is related to operation of the medical hardware. <EOS>