Page 37 - EE Times Europe Magazine - June 2025

EE|Times EUROPE 37

How a Standardized Approach Can Accelerate Development of Safety and Security in Automotive Imaging Systems

such as I C, GPIO, Ethernet, and Serial
2
Peripheral Interface for command and
control. Figure 2:
• SerDes physical layer. MIPI A-PHY is Example of
the first industry-standard, long-reach, MIPI end-
asymmetric SerDes interface with high to-end data
noise immunity. Designed specifically for protection
the automotive industry, it eliminates over a
the need for proprietary asymmetric SerDes
interfaces and bridges, thereby simplify- bridge
ing IVN design and reducing the cost and
cable harness weight. Short-reach MIPI (Source:
MIPI Alliance)
C-/D-PHY may also be used, and outside
of the MASS framework, other MIPI-
approved PHYs may be used within the
image sensor stack.
• Functional safety. Features are provided
to meet the requirements of ISO 26262
and enable designers to build systems
that meet common Automotive Safety
Integrity Level (ASIL) risks, from ASIL-B
through ASIL-D.
• Security. Incorporation of the MIPI functionality is enabled at the application • Choice of tag modes. Multiple tag mode
Camera Security Framework (see “A layer, data protection is applied end-to-end options let implementers choose how
framework for camera security” section) from the source of sensor data in the image often the security tag is computed and
enables security functionality, including sensor to the image data sink in the sensor’s transmitted.
authentication of system components, corresponding ECU. In this case, data pro- • Granular security controls. Granular
data integrity protection, and data tection is agnostic of the IVN topology and source-selective control over the dif-
encryption. can be run over any MIPI-approved physical ferent segments of each CSI-2 image
Figure 1 shows a “stack” of the image- layer interface. frame enables a sliding scale of security
sensor-related components within the MASS protection.
framework. A FRAMEWORK FOR CAMERA SECURITY • Functional safety and security. When
MASS also leverages the MIPI Camera both security and functional safety are
ADDRESSING FUNCTIONAL Security Framework, a suite of specifications enabled, security is layered on top of
SAFETY REQUIREMENTS offering a set of service extensions that can be functional safety. From a source (or trans-
The MASS framework includes functionality applied anywhere the CSI-2 imaging protocol mitter) perspective, security is applied
to meet the requirements laid out in ISO is used. Like the functional safety extensions, to the image data first, followed by the
26262, enabling systems that meet the single the camera security framework can be run application of functional safety.
point fault metric and latent fault metric over any MIPI-approved physical layer to • Protection of command and control
defined in the respective ASIL scheme, from provide end-to-end security for camera data interfaces. Defining security services
ASIL-B through ASIL-D. Functional safety and streams and I C camera command and control enables data integrity protection and
2
security (described in the next section) can be interfaces. It provides flexibility to balance optional encryption of camera command
applied end-to-end, as shown in Figure 2. required security functionality against pro- and control interfaces.
The functionality is defined within the cessing efficiency, thermal regulation, and The development of a standardized
MIPI Camera Service Extensions and MIPI power consumption. Features include: approach to functional safety and security
Command and Control Interface Service • Choice of ciphersuites. Options include in automotive imaging systems provides
Extensions specifications, which extend the an “efficiency” ciphersuite, providing several benefits to the automotive industry,
MIPI CSI-2 protocol to enable functional data integrity only (no encryption) and including reducing cost and complexity
safety at the application layer. Functional- targeted toward sensors with limited within electronic systems and driving econ-
ity includes cyclic redundancy checks for hardware resources, and a “performance” omies of scale while introducing advanced
integrity protection, a message counter to ciphersuite, which provides data integrity technologies.
detect packet loss, and a timeout monitor to and optional encryption aimed at sensors MIPI offers a variety of resources to devel-
detect loss of communication. Because this with dedicated hardware support. opers interested in learning more about these
frameworks, including two comprehensive
white papers: “An Introductory Guide to MIPI
Automotive SerDes Solutions (MASS)” and “A
Guide to the MIPI Camera Security Framework
for Automotive Applications.” ■

Philip Hawkes and Rick Wietfeldt are
co-chairs of the MIPI Security Working Group,
and Hiroo Takahashi is the MIPI Camera
Service Extensions subgroup lead, all at MIPI
Figure 1: MIPI image sensor stack (Source: MIPI Alliance) Alliance.

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