TL;DR: You’ll stop hackers from walking away with your Pi’s secrets—protecting secrets on Raspberry Pi requires hardware isolation that prevents the SD card attacks software can’t defend against.
Why Does Protecting Secrets on Raspberry Pi Matter?
In 2019, I was a software engineer working for a biotech startup. We had a biochemical process that required a lot of data collection at a lot of different points. Using standard computers for that puts a lot of strain on them. We were looking for a solution to perform data collection in tight places. The Raspberry Pi would have been a great solution.
I proposed it but was shot down for one big reason.
Security.
Someone could pick it up and walk away with the device or the memory card. Or worse, substitute a device that would scan the system and do many bad things. Stop the process, grab all of our code and data, etc.
With the state of technology that we knew about then, using the Raspberry Pi was a terrible idea.
Raspberry Pi devices are increasingly moving from hobbyist projects to mission-critical deployments. Yet many developers overlook a fundamental vulnerability: inadequate approaches to protecting secrets on Raspberry Pi devices. Encryption keys, API credentials, and certificates must be properly secured, and while software-based security measures might seem adequate, they leave critical vulnerabilities that only hardware security can address effectively.
This post is sponsored by Zymbit.
Key Takeaways
- Software-only approaches to protecting secrets on Raspberry Pi leave vulnerabilities to physical access attacks, memory dumps, and code extraction.
- Hardware security modules like ZYMKEY4 provide physical isolation of secrets that software alone cannot achieve.
- Physical access vulnerabilities are the most overlooked security risk for Raspberry Pi devices in production.
- Proper hardware security implementation decreases both the attack surface and potential impact of breaches.
- Implementing hardware security early in development is significantly easier than retrofitting it later.
Why Are Your Raspberry Pi Secrets at Risk?
The transition from prototype to production creates a security gap many developers fail to recognize. While a Raspberry Pi might adequately serve your development needs with minimal security precautions, the same approach creates substantial vulnerabilities when deployed in the field. Community discussions on the Raspberry Pi Forums highlight common security misconceptions when transitioning projects to production environments
The primary issue stems from a fundamental problem: in software-only security approaches, the secrets that protect your system (encryption keys, credentials, certificates) must exist somewhere within the same system they’re meant to protect. This creates an inherent vulnerability—if an attacker gains access to your system, they potentially gain access to the very keys designed to keep them out.
How Easy Is It to Extract SD Card Secrets?
Physical access to Raspberry Pi devices presents one of the most significant security vulnerabilities. Unlike enterprise hardware with secure enclosures, most Pi deployments use standard plastic cases providing minimal physical security. This creates a substantial attack vector most developers overlook.
The most straightforward attack involves simply removing the SD card. Once an attacker physically possesses this storage medium, they can easily mount it on another computer and access all unencrypted files. Even if you’ve implemented filesystem encryption, if the encryption keys are stored on the same SD card (as is common in software-only approaches), an attacker can often recover them through careful analysis. This vulnerability exists because standard Pi setups have no secure storage mechanism isolated from the primary storage.
Once they have the card, they can figure out how to bypass the boot chain and gain root access.
Consider a real-world scenario: an attacker gains brief access to your Pi-powered kiosk, surveillance system, or industrial controller. In just minutes, they can clone the entire SD card, return the original device to service (leaving no evidence of tampering), and extract sensitive information from the copy at their leisure.
What Makes Memory Attacks So Dangerous?
Even without physical removal of storage media, Raspberry Pi devices remain vulnerable to memory-based attacks during operation. When your application runs, encryption keys and other secrets must be loaded into RAM to be used for cryptographic operations. This creates a critical exposure point for sensitive data.
Memory dumping attacks allow adversaries who gain execution privileges to extract the contents of RAM, revealing any secrets currently in use. Common tools can capture a complete memory image or target specific memory regions where encryption keys might reside. What makes these attacks particularly insidious is that they can succeed even when filesystem encryption is properly implemented—because once the system is running, the secrets must exist in memory to be useful.
Many developers mistakenly believe that clearing variables after use provides adequate protection. However, due to how memory management works in modern operating systems, copies of sensitive data often persist in various memory locations, swap files, or process spaces long after your code attempts to erase them.
How Do Code and Deployment Practices Expose Secrets?
Beyond physical and memory vulnerabilities, common development and deployment practices create additional security gaps. The most prevalent among these is hardcoding secrets directly in application code, configuration files, or environment variables. Hardware developers have discussed the challenges of protecting proprietary code on Raspberry Pi devices, noting the inherent vulnerabilities of SD card storage.
When secrets are embedded in code or configuration, they travel with that code through your entire development pipeline. This means they’re stored in version control systems, possibly emailed between team members, included in backups, and potentially exposed in multiple locations. A 2025 study found that over 23 million secrets found in public GitHub repositories including hardcoded API keys and credentials, demonstrating the scale of this problem. Once these secrets leak, they’re effectively compromised forever.
Additionally, hardcoded secrets create a key rotation nightmare. When credentials need to be updated (following best practices or after a suspected breach), every device must receive code or configuration updates. For distributed deployments with dozens or hundreds of devices, this creates significant operational challenges and extends the window of vulnerability.
Why Is Hardware Security Essential for Protecting Secrets on Raspberry Pi?
Hardware security fundamentally changes the security equation by physically isolating secrets from the main system. This approach creates a separate security domain that remains protected even if the main system is compromised.
Once the device can be opened, a device like the Chip Whisperer can be used to watch the computer running and reverse engineer what is happening inside the computer. If they can open up the computer, they can do that.
At its core, hardware security relies on dedicated silicon designed specifically for cryptographic operations and secure storage. These specialized components—often called secure elements—implement physical security measures that resist tampering, side-channel analysis, and other sophisticated attacks. By keeping sensitive operations within this protected boundary, the overall security posture dramatically improves.
Hardware security modules provide several critical capabilities for Raspberry Pi deployments:
- Physical isolation of cryptographic keys and operations
- Tamper detection and response mechanisms
- Encrypted communication with the host CPU to protect against sniffing of HSM/CPU communication
- True random number generation for strong cryptographic operations
- Secure boot verification
- Hardware-based device identity that can’t be cloned by monitoring the system fingerprint
- Detects and responds to power supply attacks
Security experts at emphasize the importance of hardware-based protection for IoT products built on Raspberry Pi.
These capabilities establish a hardware root of trust—a foundation for security that doesn’t rely on the integrity of the main system software, which could potentially be compromised.
How Does the ZYMKEY4 Protect Against Physical Access Threats?
Purpose-built hardware security modules like the ZYMKEY4 are specifically designed to address Raspberry Pi’s security vulnerabilities. These compact modules integrate directly with the Pi’s GPIO pins to provide enterprise-grade security capabilities in an accessible form factor.
The ZYMKEY4’s File System Encryption capabilities provide a crucial defense against SD card extraction attacks. Unlike software-only encryption, ZYMKEY4 stores the master encryption keys within its secure element—not on the SD card itself. This means that even if an attacker removes and mounts the SD card on another system, the encrypted data remains protected because the decryption keys remain safely inside the hardware module on the original device.
The module’s Device Binding functionality creates a unique association between the security hardware and your specific Raspberry Pi. This prevents cloning attacks by ensuring that even if an attacker creates a perfect copy of your SD card, the cloned system cannot access protected resources without the original hardware security module, which contains unique cryptographic material that cannot be extracted or duplicated.
For physical attack detection, the ZYMKEY4 includes Tamper Detection sensors that monitor for unauthorized access attempts. These can detect chassis intrusion, device movement, or attempts to probe the hardware ports. When tampering is detected, the module can automatically erase sensitive keys or lock down the system, preventing compromise even in hostile physical environments.
How Does Hardware Security Prevent Memory Attacks?
Hardware security modules fundamentally change how cryptographic operations function on your Raspberry Pi, eliminating many of the vulnerabilities associated with memory-based attacks.
The most significant protection comes from Secure Element Processing, which executes cryptographic operations entirely within the isolated secure element—not in the main Raspberry Pi processor. When your application needs to encrypt data or verify a signature, it sends the operation request and data to the hardware module, which performs the computation within its protected boundary and returns only the result. This approach ensures that sensitive keys never enter the Pi’s main memory, making memory dump attacks ineffective.
Hardware security modules like the ZYMKEY4 provide isolated secure element processing that keeps cryptographic operations separate from the Raspberry Pi’s vulnerable main memory.
Key Isolation is the cornerstone of this security model. Private keys generated within the secure element never leave its protected environment. Instead of extracting keys for operations, your application uses an API-Based Access model where cryptographic functions are performed by sending commands to the hardware module. This eliminates the need to store or transmit raw key material within your application code or main memory.
For added protection, communication between your application and the hardware security module uses Encrypted Communication channels, preventing eavesdropping on the data exchanges between your software and the security hardware.
How Does Hardware Security Improve Deployment Security?
Implementing hardware security transforms how secrets are managed throughout the development and deployment lifecycle of Raspberry Pi projects. This shift addresses many of the inherent vulnerabilities of software-only approaches.
With hardware security modules, developers can replace hardcoded secrets with API calls to the security hardware. Instead of embedding API keys or encryption keys directly in code, applications request cryptographic operations from the hardware module as needed. This dramatically reduces the risk of secret exposure through code repositories, backups, or inadvertent sharing.
Secure Key Management capabilities enable proper key lifecycle handling—including secure generation, storage, rotation, and eventual destruction. When credentials need to be updated, this can be managed in a controlled fashion without requiring complete redeployment of application code. The hardware module can maintain multiple key versions or implement grace periods during rotation to ensure system continuity.
For maintaining system integrity during updates, Secure Boot functionality verifies the authenticity of firmware and software before execution. This prevents the installation of unauthorized or malicious code, even if an attacker gains write access to the storage media. Combined with A/B Partition Updates through complementary systems like Bootware, this creates a robust update pipeline resistant to tampering or corruption.
When Should You Implement Hardware Security?
The ideal time to implement hardware security is early in the development cycle, though it’s never too late to improve your security posture. By incorporating hardware security from the beginning, you can design your architecture with security as a foundational element rather than an afterthought. Discussions among home lab enthusiasts reveal the varying security needs based on application sensitivity and deployment environment.
For existing projects transitioning from prototype to production, adding hardware security should be considered a critical milestone. The marginal cost of adding hardware security is typically minimal compared to the potential cost of a security breach. Even for budget-conscious projects, entry-level hardware security modules like the ZYMKEY4 provide substantial protection at accessible price points.
Consider these factors when evaluating hardware security implementation:
- Application sensitivity: Does your application handle financial, personal, or proprietary data?
- Deployment environment: Will devices operate in physically accessible or untrusted locations?
- Scale considerations: How many devices will be deployed, and how will you manage them?
- Compliance requirements: Do you need to meet specific industry regulations or standards?
Remember that retrofitting security after a breach is significantly more costly—both financially and reputationally—than implementing proper protection from the start.
Frequently Asked Questions
Can a Raspberry Pi be secure without hardware security?
While basic software security measures provide some protection, Raspberry Pi devices without hardware security remain vulnerable to physical access attacks, memory dumps, and key extraction. For non-critical hobbyist projects, software security may be adequate, but any production deployment handling sensitive data should implement hardware-based protection.
How much does hardware security add to project costs?
Entry-level hardware security modules for Raspberry Pi typically range from $15-50, representing a small percentage of overall project costs for most deployments. This modest investment significantly reduces security risks that could result in much larger financial impacts from breaches.
Is the ZYMKEY4 difficult to integrate with existing Raspberry Pi projects?
Most projects can integrate the ZYMKEY4 with minimal code changes by using the provided APIs. The module connects directly to GPIO pins and includes libraries for Python and C/C++. Typically, security integration requires replacing hardcoded secrets with API calls to the hardware module.
Can hardware security modules prevent all types of attacks?
No security solution prevents all possible attacks. Hardware security modules significantly raise the difficulty of attacks by protecting against common vulnerabilities, but they must be part of a comprehensive security strategy that includes proper authentication, network security, and regular updates.
Do I need hardware security for development and testing environments?
While development environments don’t strictly require hardware security, implementing it early helps identify integration issues and ensures your architecture properly supports hardware-based key management. Some teams use hardware modules in later testing phases to match production environments.
How does hardware security impact Raspberry Pi performance?
Modern hardware security modules have minimal performance impact for most applications. Cryptographic operations may take slightly longer when performed in secure hardware compared to software, but this difference is negligible for typical use cases and is offset by the significant security improvements.
Conclusion: Building Truly Secure Raspberry Pi Deployments
The transition of Raspberry Pi from hobbyist tool to production-grade computing platform demands a parallel evolution in security approaches. While software security measures provide some protection, they ultimately fail to address the fundamental vulnerabilities inherent in protecting secrets on Raspberry Pi devices when the secrets are accessible to the same system they protect.
Hardware security modules like the ZYMKEY4 create the necessary physical boundary between your secrets and potential attackers. By isolating cryptographic operations, protecting keys from extraction, detecting tampering, and enabling secure updates, hardware security transforms a vulnerable Raspberry Pi into a hardened computing platform suitable for mission-critical applications.
As you build your next Raspberry Pi project, consider security requirements from the earliest planning stages. Implementing hardware security is an investment that protects not just your data and intellectual property, but also your reputation and the trust of your users. The modest additional cost and development effort pay dividends in reduced risk and increased resilience throughout your deployment’s lifecycle.
I am a retired software engineer with experience in a multitude of areas including managing AWS and VMWare development environments. I bought a relative a mini-PC a year ago and have become passionate about the technology and its potential to change how we deploy software.