So far, only five companies have launched HomeKit-certified smart home devices. What’s the hold up? Apple has thrown a plethora of challenges at hardware makers, and some developers say one of the biggest is complying with Apple’s strict security requirements on Bluetooth low energy devices.
Apple allows for either WiFi or Bluetooth low energy (LE)-enabled devices to get certified as a HomeKit accessory. Apple is requiring device makers using both WiFi and Bluetooth LE to use complicated encryption with 3072-bit keys, as well as the super secure Curve25519, which is an elliptic curve used for digital signatures and exchanging encrypted keys.
Read more: http://www.forbes.com/sites/aarontilley/2015/07/21/whats-the-hold-up-for-apples-homekit/