Electronic connectors are normally designed with one primary objective: maintain a reliable electrical connection throughout the expected operating conditions of a product.
But in security-sensitive electronics, there may be another important requirement:
What happens to the interconnect if someone attempts to open, modify, or reassemble the device?
For products where physical tampering is a concern, an elastomeric connector can potentially become part of the product’s tamper-resistant mechanical design.
Rather than designing the connector to survive every possible mechanical condition, the interconnect can be engineered around a defined mechanical operating envelope. Under normal assembly conditions, the connector provides reliable electrical contact. If the device is manipulated in a way that subjects the connector to excessive compression or other conditions outside that envelope, the interconnect may become permanently deformed or damaged.
This concept can be useful in security-sensitive products such as hardware wallets, authentication devices, payment terminals, encrypted storage devices, access-control systems, and other electronics where unauthorized physical access is a concern.
Controlled Compression of Elastomeric Connectors
Z-Axis wire-based elastomeric connectors use vertically oriented conductive elements embedded within silicone rubber. Electrical contact is established by compressing the elastomer between two mating contact surfaces.
Under normal conditions, the connector is designed to operate within a specified compression range. The mechanical assembly controls the connector height and compression so that consistent electrical contact is maintained.
For a security-sensitive application, those mechanical limits can also become part of the product’s tamper-resistant architecture.
A connector and enclosure can potentially be designed so that:
- Normal assembly produces the intended connector compression and reliable electrical contact.
- Opening, removing, or manipulating components changes the mechanical relationship of the assembly.
- Unauthorized reassembly can expose the connector to excessive compression or altered compression conditions.
- Compression beyond the qualified range can permanently deform or damage the interconnect, preventing the device from simply being returned to its original condition.
Using the Interconnect as Part of the Security Architecture
The key is establishing a clear distinction between normal operating compression and abnormal or destructive compression.
During normal operation, the connector remains within its qualified compression range and provides a reliable electrical connection.
If tampering causes the assembly to exceed those mechanical limits, the connector may experience irreversible deformation or damage.
This creates the possibility of an interconnect serving two functions:
During normal operation: provide a reliable, compact electrical connection.
During a tamper event: act as a mechanical element that makes unauthorized disassembly and reassembly more difficult without affecting the interconnect.
The exact behavior must be characterized through testing, particularly when connector deformation or electrical failure is intentionally incorporated into a security strategy.
Applications for Tamper-Resistant Interconnects
This approach can potentially be applied anywhere physical access to sensitive electronics must be controlled.
Examples include hardware wallets used to protect cryptographic keys, payment and point-of-sale devices, secure authentication products, encrypted storage systems, access-control electronics, security modules, and other devices containing sensitive information or functionality.
In these applications, the electrical connector can be considered as more than simply a means of transferring signals between two surfaces.
It can become part of the mechanical security architecture of the product itself.
Developing a Custom Elastomeric Interconnect
Z-Axis Connector Company develops custom wire-based elastomeric connectors for applications requiring precise mechanical and electrical performance.
Connector dimensions, conductive element pitch, compression, contact geometry, and mechanical integration can be tailored to the application.
For applications involving unusual compression requirements or tamper-resistant designs, connector behavior can also be evaluated through prototype testing to establish the appropriate operating and failure conditions.
If you are developing a security-sensitive electronic product and need an interconnect with a defined mechanical operating range, contact Z-Axis Connector Company to discuss your application