PKI for IoT

"Public Key Infrastructure" or PKI is based on asymmetric cryptography, which uses pairs of cryptographic keys: a private key and a public key. The private key is kept secret and known only to the owner, while the public key is freely distributed. These keys are mathematically related, allowing data encrypted with one key to be decrypted with the other.

A central component of this concept is the Certificate Authority (CA) that issues digital certificates. These certificates bind the identity of an entity, such as a person, organization, or device, to its public key. The CA digitally signs the certificates, verifying their authenticity and integrity.

Over the last two decades PKI has proven itself to be a robust framework for establishing trust, confidentiality, and data integrity in digital communications and is now widely used in various applications, including secure email, secure web browsing (HTTPS) and virtual private networks (VPNs) to name a few.

Due to its security properties PKI reliably meets current industry standards for IoT system security and is now considered the most secure method for managing the vast network of interconnected devices in the Internet of Things. Here are some ways how it is used:

Device Authentication

Each IoT device is issued a unique digital certificate, that contain the device's public key and other identifying information. By verifying the certificate, other devices or services can ensure the authenticity of the IoT device.

Secure Communication

IoT devices can use their digital certificates to establish secure connections using protocols like Transport Layer Security (TLS). This ensures that the communication between devices and other entities such as gateways, cloud platforms, or applications, is protected from eavesdropping or tampering.

Data Integrity

IoT devices can digitally sign the data they produce using their private keys. The receivers can then verify the digital signature using the device's public key, ensuring that the data has not been tampered with during transmission.

Secure Firmware

IoT device firmware (as well as firmware updates) can be signed with the manufacturer's private key, enabling IoT devices to verify the authenticity and integrity using the manufacturer's public key. This ensures that only authorized and trusted firmware is installed, mitigating the risk of unauthorized modifications or malicious code.