By Patrick Carrier, Business Development, Connected Secure Systems, Infineon

Our homes are becoming smarter as individual appliances and larger local infrastructure gain connectivity and processing power. These systems are connecting to each other and to the Internet, as well as integrating with voice interfaces like Amazon Alexa, Apple Siri and Hey Google, to create sophisticated home automation schemes. Who would have thought, ten years ago, that it would be possible to say “Movie Night” and close the doors and windows of your house, pull down the curtains, turn off the lights, set the room temperature and turn on the TV ? But this is very achievable today.

Smart-home technology promises many other ways to make our lives easier and more convenient, from lighting scheduling schedules to automated garage doors. What is less noticeable is the work that is needed to enable this convenience by ensuring that smart homes keep residents and their data safe. As we begin to realize, more than 15 years after we started owning smartphones, our online data trail is incredibly revealing of our lives and actions, desires and failures. The data collected from our homes will be even more revealing. If our homes are our sanctuaries, poorly secured smart home technology threatens, at least metaphorically, to tear down curtains, place floor-to-ceiling windows, and build a viewing gallery for curious passersby.

Given the potential value of data related to activities within our homes, there are many incentives to abuse smart home technology for profit. One of the simplest approaches to doing this is for legitimate smart home technology to collect and disseminate information on how to use it: anyone who has monitored the network connections a smart TV makes when connected to the internet will be familiar with this approach to the acquisition of personal data for commercial gain. Another mass-scale approach is to cross the Internet for poorly secured Internet of Things (IoT) devices, and then merge them into botnets that can be used to launch denial of service attacks for political or financial gain.

Perhaps the most disturbing type of hacking, however, is one that utilizes smart home technology to attack an individual. In December 2020, the U.S. Federal Bureau of Investigation warned that hackers are now using compromised smart home devices to orchestrate ‘widespread’ attacks. Hackers use stolen credentials to identify themselves on the victim’s live stream camera and / or smart speaker. They then call the emergency services to report that a crime is taking place at home. Once the responding police arrive, the hackers watch the action through the camera and interact with the police through the loudspeaker. In some cases, hackers transmit the attack online.

The challenge of securing a smart home

As smart home technology becomes more complex and widely used, the challenge of securing it increases.

One of the most basic parts of IoT security, of which the smart home is a special case, is device authentication – in other words, finding a way to prove that every device on a network is legitimate and not cloned. This means giving each device a unique identifier, ideally kept in the hardware, which cannot be changed or copied. The unique identifier can then be used as the basis for a series of trust-building steps between the two devices, enabling them to verify their identities. Once this is done, it is possible to create a secret that separates the two devices, which is then used to enable secure communications between them.

Another key aspect of securing smart home devices involves ensuring that any firmware downloads they receive are legitimate. This involves two steps. The first is to make sure each firmware update source signs the code it sends, so that the smart device can check that it came from a legitimate source. The second step is to give the smart device a way to check that the code has not been changed during transport. If the signature is not recognized as a valid resource or the shipment appears to have changed during shipping, then the update should be refused.

This is obviously important from a practical device security standpoint, but it is also becoming a requirement of evolving IoT standards, accreditation schemes and regulations. If a vendor cannot show that it can update the firmware of a device safely on the ground, the devices may be locked out of some markets. Some regulators even want device providers to offer a “better cash” date at the point of sale so that buyers know how long they can expect sellers to maintain the security of their devices. This would require a greater commitment from appliance manufacturers in the smart home market than those selling general consumer electronics.

Secure communication, using encryption schemes that refer to the unique ID of a device, is also very important to protect data integrity and user privacy in smart home configurations. For example, the sound that is captured by a voice assistant needs to be encrypted to secure its journey to cloud servers that provide voice recognition services. Video data transmitted by nanny cameras must be encrypted to ensure privacy. Other devices that collect and transmit data, such as thermostats and air quality monitors, must also be securely authenticated and use encryption to protect the integrity of the data they transmit so as not to be corrupted or misused. . Because we use sensors to secure the information that automated systems use to make decisions about their actions, injecting false information into a sensor data stream can have serious consequences. For example, if someone manipulates your thermostat data to show warmer temperatures in your home than they actually were, this can cause your air conditioning (A / C) to run continuously. Worse, if thousands of thermostats are hacked into a city so that all A / C units turn on instantly, it can tax the power grid to the point of causing an outage.

A solution to secure the smart home

Security controller ICs such as OPTIGATM Trust M from Infineon, also known as Embedded Secure Elements (eSE). They are designed to provide the tools needed to secure smart home devices and networks.

These ICs provide a layer of physical security by addressing security functions on a separate device isolated from the main application processor of an intelligent home device. Each has a secure storage which can hold arbitrary user data and cryptographic keys either generated on the device or programmed on the device during its production in a secure structure. The devices are resistant to manipulation, so trying to physically extract secret information will destroy it. Some retailers, including Infineon, also run their own certification authorities, so it is possible to certify each device as a genuine part of Infineon.

Such ESEs can hold secret keys for use in symmetric cryptographic schemes, they can create pairs of cryptographic keys for use in asymmetric cryptographic schemes and create secure communication channels. Public keys of cryptographic key pairs can also be used to create a certificate, which can later be used to verify the identity of a device.

eSEs can also be programmed with the credentials needed to automatically make secure connections to cloud servers, such as Amazon Web Services, at startup.

Figure 1 System Block Diagram

Successful security means paying attention to detail – all the details. For example, eSEs should protect the exchange of their information with a host application processor using a secure communication channel. For another level of security, an eSE may be given a single-use key that it uses to perform an exchange with the application processor to ‘cryptographically’ link the two parts together when the system restarts first. This prevents the security controller from working with any other processor, even if the part is freed from one table and used in another, protecting its secrets from misuse.

ESE can create pairs of cryptographic keys, generate random numbers, compute cryptographic hashes, and handle various forms of encryption and decryption directly. Some security controllers are also being designed with a view to the future, supporting longer key lengths than those currently in use, in order to remain relevant as OEMs move to more robust cryptographic schemes.

Security controllers with this feature set provide a solid foundation on which to build a secure “trust chain” within smart home devices and networks. Each security controller can be given a unique, secret user ID and cryptographic keys. These are hardware protected, so any device can be authenticated and private information remains confidential. Cryptographic keys and functions enable the creation of secure communication channels, both online and within home networks, to protect data integrity and user privacy.

Smart homes can simplify our home life by automating all sorts of basic functions within our homes. This promise of greater comfort and convenience must be mitigated by concerns about the integrity of the devices and networks that enable it, and the privacy of the data about our lives that these systems capture. eSEs can provide many of the basic building blocks needed to create and maintain the integrity and privacy of smart home devices and systems.

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