Series 2 and Series 3 Device Security Features#

Protecting IoT devices against security threats is central to a quality product. Silicon Labs offers several security options to help developers build secure devices, secure application software, and secure paths of communication to manage those devices. Silicon Labs’ security offerings were significantly enhanced by the introduction of the Series 2 and Series 3 products that included a Secure Engine. The Secure Engine is a tamper-resistant component used to securely store sensitive data and keys and to execute cryptographic functions and secure services.

On Series 1 devices, the security features are implemented by the TRNG (if available) and CRYPTO peripherals.

On Series 2 and Series 3 devices, the security features are implemented by the Secure Engine and CRYPTOACC (if available). The Secure Engine may be hardware-based, or virtual (software-based). Throughout this document, the following abbreviations are used:

• Series 2 devices: EFR32xx2xx devices

• Series 3 devices: SiG3xxx devices

• HSE: Hardware Secure Engine

• VSE: Virtual Secure Engine

• SE: Secure Engine (either HSE or VSE)

Additional security features are provided by Secure Vault. Three levels of Secure Vault feature support are available, depending on the part and SE implementation, as reflected in the following table:

Notes:

1. The features of different Secure Vault levels can be found in Security.

2. Refer to IoT Endpoint Security Fundamentals for details on supporting devices.

Secure Vault Mid consists of two core security functions:

• Secure Boot: Process where the initial boot phase is executed from an immutable memory (such as ROM) and where code is authenticated before being authorized for execution.

• Secure Debug access control: The ability to lock access to the debug ports for operational security, and to securely unlock them when access is required by an authorized entity.

Secure Vault High and Series 3 Secure Vault devices offer additional security options:

• Secure Key Storage: Protects cryptographic keys by “wrapping” or encrypting the keys using a root key known only to the HSE-SVH.

• Anti-Tamper protection: A configurable module to protect the device against tamper attacks.

• Device authentication: Functionality that uses a secure device identity certificate along with digital signatures to verify the source or target of device communications.

Note: Series 3 Secure Vault devices do not include a device certificate for the host MCU.

A Secure Engine Manager and other tools allow users to configure and control their devices both in-house during testing and manufacturing, and after the device is in the field.

User Assistance#

In support of these products, Silicon Labs offers whitepapers, webinars, and documentation. The following table summarizes the key security documents:

Key Reference#

Public/Private keypairs along with other keys are used throughout Silicon Labs security implementations. Because terminology can sometimes be confusing, the following table lists the key names, their applicability, and the documentation where they are used.

SE Firmware#

Silicon Labs strongly recommends installing the latest SE firmware on Series 2 and Series 3 devices to support the required security features. Refer to Production Programming of Series 2 and Series 3 Devices for the procedure to upgrade the SE firmware and IoT Endpoint Security Fundamentals for the latest SE Firmware shipped with Series 2 and Series 3 devices and modules.