The Top Internet of Things (IoT) Authentication Methods and Options – Security Boulevard

Gartner recently labeled Internet of Things Authentication as a high benefit in 2020 Gartner Hype Cycle for IAM Technologies. This blog covers your options for Internet of Things Authentication.

Want to read the report? Skip the blog and click Download Report below.

IoT authentication is a model for building trust in the identity of IoT machines and devicesto protectdataand control access wheninformation travelsvia an unsecured network such as the Internet.

Strong IoT authentication is needed so that connected IoTdevices andmachines can be trusted to protect against control commands from unauthorized usersordevices.

Authentication also helps prevent attackers from claiming to be IoT devices in the hope of accessing data on servers such as recorded conversations, images, and other potentially sensitive information.

There are several methods by which we can achieve strong authenticationto secureIoT device communications:

The Internet of Things (IoT) is not just a single technology, but a connected environment of various machines (things) that work together independently without human interaction.

The authorization process is the tool used to validate the identity ofeach endpoint in the IoT system. The certification process is configureduponenrollment entry and informs the service provider of the method to be used when checking the systems identity during registration.

Machine Identity Management aims to build and manage confidence in a machines identity that interacts with other devices, applications, clouds, and gateways.

This may include the authentication and authorization of IoT devices such as:

Each IoTmachineneeds a unique digital identity when connecting to a gateway or a central server to prevent malicious actors from gaining control of the system.This is accomplished through binding an identity to a cryptographic key, unique per IoT device.

Machine identity management approaches are specifically responsible for discovering the credentials used by machines and the management of their life cycle.

IoT devices are often hacked remotely, involving a hacker trying to enter the device using an internet connection. If an IoT device is only allowed to communicate with an authenticated server, any outside attempts to communicate will be ignored.

According to the 2018 Symantec threat report, the number of IoT attacks increased by 600 percent between 2016 and 2017, from 6,000 to 50,000 attacks, respectively.

Therefore, when IoTdevices areimplemented within corporate networks,,security needs to be given much more attention. To address this issue, powerful but efficient cryptography solutions must be used to standardize secure communication between machines.

However, it is a tough decision to choose the right IoT authentication model for the job. Before deciding whicharchitecturemodel is ultimately the best IoT authentication, you need toconsiderseveralfactors, such as energy resources, hardware capacity, financial budgets, security expertise, security requirements, and connectivity.

The X.509 protocol (IETF RFC 5280) provides the most secure digital identity authentication type and is based on the certificate chain of trust model. The use of X.509 certificates as a certification mechanism is an excellent way to scale up production and simplify equipment delivery.

Public key infrastructure (PKI) consists of a tree-like structure of servers and devices that maintain a list of trusted root certificates. Each certificate contains the devices public key and is signed with the CA private key. A unique thumbprint provides a unique identity that can be validated by running a crypto algorithm, such as RSA.

Digital certificates are typically arranged in a chain of certificates in which each certificate is signed by the private key of another trusted certificate, and the chain must return to a globally trusted root certificate. This arrangement establishes a delegated chain of trust from the trusted root certificate authority (CA) to the final entity leaf certificate installed on the device through each intermediate CA.

It requires a lot of management control, but there are many vendor options out there.

However, X.509 certificate lifecycle management can be a challenge due to the logistical complexities involved and comes at a price, adding to the overall solution cost. For this reason, many customers rely on external vendors for certificatesand lifecycle automation.

The Hardware Security Module, or HSM, is used for secure, hardware-based device secret storage and is the safest form of secret storage. Both the X.509 certificate and the SAS token can be stored in the HSM. HSMs may be used with the two attestation mechanisms supported by the provisioning service.

Alternatively, device secrets may also be stored in software (memory) but is a less secure form of storage compared to an HSM.

It is essential to check the devices identity that communicates with the messaging gateway in IoT authentication deployments. The usual method is to generate key pairs for devices that are then used to authenticate and encrypt traffic. However, the disk-based key pairs are susceptible to tampering.

TPMs come ina number ofdifferent forms, including:

While a typical TPM has several cryptographic capabilities, three key features are relevant to IoT authentication:

Device manufacturerscannotalways have full confidence in all entities in their supply chain (for example, offshore assembly plants). Still, theycannotgive up the economic benefits of using low-cost suppliers and facilities. The TPM can be used at various points along the supply chain to verify that the device has not been incorrectly modified.

The TPMhas the capability to storethe keyssecurelyin the tamper-resistant hardware. The keys are generated within the TPM itself and are therefore protected from being retrieved by external programs. Even without harnessing the capabilities of a trusted hardware root and a secure boot, the TPM is just as valuable as a hardware key store. Private keys are protected by hardware and offer much better protection than a software key.

With TPM, you cant roll the key without destroying the identity of the chip and giving it a new one. Its like if you had a clone,yourclone would have the same physical characteristics as you, but theyre a different person in the end. Although the physical chip remains the same, your IoT solution has a new identity.

Some key differences between TPMs and symmetric keys (discussed further below) are as follows:

Symmetric Key Certification is a simple approach to authenticating a device with a Device Provisioning Service instance. This certification method is the Hello World experience for developers who are new to or do not have strict safety requirements. Device attestation using a TPM or an X.509 certificate is more secure and should be used for more stringent safety requirements.

Symmetric key enrollments also provide a great way for legacy devices with limited security features to boot into the cloud via Azure IoT.

The symmetric key attestation with the Device Provisioning Service is carried out using the same security tokens supported by IoT hubs to identify the devices. These security tokens are SAS (Shared Access Signature) tokens.

SAS tokens have a hashed signature created using a symmetric key. The signature shall be recreated by the Device Provisioning Service to verifywhether or notthe security token presented during the certification is authentic.

When the device certifies with an individual enrollment, the device uses the symmetric key defined in the individual enrollment entry to create a hashed signature for the SAS token.

Shared symmetric keys may beless secure than X.509 or TPM certificates because the same key is shared between the device and the cloud, which means that the key needs to be protected in two places.Designers usingsymmetric keyssometimeshardcode the clear (unencrypted) keys on the device, leaving the keys vulnerable, which is not a recommended practice

Properimplementation of IoT authenticationhasmany beneficial effects on IoT security. However, choosing the right method can be challenging, and the wrong choice can increase risks by tenfold.

Some riskscan be mitigated by securely storing the symmetric key on the deviceand following best practices around key storage,Its not impossible, butwhensymmetric keys areused solely,theycan beless secure then HSM, TPM, and X.509 implementations.

In the case of certificates, HSM, TPMs, and X.509applications, the main challenge is to prove possession of the key without revealing the keys private portion.

More:
The Top Internet of Things (IoT) Authentication Methods and Options - Security Boulevard