Matter smart home standard is a key step forward for network security

My favorite point about the interoperability standard of Matter smart home is that even though it can’t easily manage complex smart home from the beginning (or eventually, forever), it does put forward some basic security requirements for networking devices. This is a big event!

The Matter standard was created by well-known enterprises in the smart home industry such as Amazon, Apple, Google and Samsung, aiming to make smart home more interoperable and reliable. Therefore, the Matter devices will collaborate with each other and be able to communicate on the home LAN using a standard data model. The standard also requires that these devices be safe.

With the official release of the Material standard last week, the Connection Standards Alliance released a massive document describing the standard and a software development kit that implements the standard on devices. Companies are still absorbing and learning the complete standards, but in terms of safety, the following are required to become Matter equipment.

The Matter standard attempts to address two security challenges. The first is related to the device itself, because it determines whether the device is running security software that is not vulnerable to hackers. The second one focuses on the network to determine whether the device is a legitimate Matter device on the network. Imagine your home network as a private club and Matter as a security guard. Try to ensure that only members can enter, and that these members have met a specific set of standards, which means they can be trusted.

To this end, all Matter devices must use encryption. These devices only need to encrypt data between each other, not between them and the cloud. It does not specify how device data is stored in the cloud, which is somewhat disappointing.

It also requires that the Matter device can be updated wirelessly. This is another basic requirement for network security, because new vulnerabilities that need to be repaired will be found at any time. However, it is disappointing that the Material standard does not require suppliers to repair their equipment.

More hopefully, Material needs code signature. Code signature refers to that developers affix certificates or seals on their code to indicate that they have reviewed and verified that it is real code. The code signature guarantees the user that the code is valid and has not been tampered with. If a device enters the network without such a certificate, other Matter devices can identify it as illegal and avoid it.

Matter also requires a security zone on the chip to store keys and certificates as the next layer of security functions: trust and identification. This is where blockchain ledgers come into play. Remember the metaphor of a private club? The previous examples of Matter security requirements are all about reviewing members, and devices must meet these requirements to become part of the Matter network.

The next section of the security requirements specifies how to build trust and identify members of the Matter Club. Matter needs to use public key encryption or PKI and certificate to establish trust and manage device identity.

It all starts with trusted root permissions. At present, two organizations (DigiCert and StrongKey) are authorized to act as the trusted root of Matter. According to Mike Nelson, DigiCert’s vice president of IoT security, the company has spent eight months building this capability. In the words of Matter, this root issuer is called a product certification authority, or PAA.

PAA grants authority by issuing certificates to other companies. Companies with authority to grant certificates are called product certification intermediaries, or PAIs; Its function is to issue a certificate, which will be used by the Matter device to prove to other Matter devices that they have obtained the Matter authentication when joining the network, and will be used for future communication. These certificates are called equipment certificates or DACs.

Companies can cooperate with PAA to issue their own certificates, or with independent PAA to issue certificates on their behalf. In the case of DigiCert, it serves as the initial PAA, but it can also serve as a PAI to release DAC. Companies such as Amazon and other large smart home device manufacturers can also cooperate with DigiCert to become PAI, so as to release their own DAC. If they want to build infrastructure to become trusted roots, they can also become PAAs.

All issued DACs are placed in the blockchain ledger, so you can check the devices to ensure that they have been certified by Matter and that they are manufactured by the company the device claims. The ledger is the register of club members, and the certificate proves that the equipment is a member of the club.

As you can imagine, all this will cost money. DigiCert declined to disclose its certificate charging standard, but pointed out that it would depend on the number of devices. The more devices, the lower the cost per DAC.

In addition, there are other costs to consider, such as the cost of updating the connectivity and engineering of the device during its life cycle, and the cost of adding a security zone to the chip on the device (most manufacturers have done this for some time, but it is still worth noting). However, although Matter’s concern about safety will increase the bill of materials and final cost of equipment, it is necessary to pay for safety. Of course, there is another option, that is, we pay for less secure equipment.

Post time: Oct-25-2022