So, what’s new at wolfSSL? Take a look below to check out the most recent news, or sign up to receive weekly email notifications containing the latest news from wolfSSL. wolfSSL also has a support-specific blog page dedicated to answering some of the more commonly received support questions.

Building Qt 5.15 with wolfSSL Support

Did you know that you can build Qt 5.15 against the wolfSSL embedded SSL/TLS library instead of the default OpenSSL backend? Using wolfSSL as the TLS provider in Qt offers many advantages depending on application and industry. Some of these may include:

To compile wolfSSL for Qt, use the following configure options:

$ cd wolfssl
$ ./
$ ./configure  --enable-qt --enable-qt-test --enable-alpn --enable-rc2 --prefix=/path/to/wolfssl-install\
$ make
$ make install

Depending on the environment, adding wolfSSL install path to LD_LIBRARY_PATH for Qt build


To compile Qt with the wolfSSL follow the steps below:

  1. Follow the Building Qt Guide to download needed Qt dependencies and initialize the Qt repository. To clone Qt for v5.15.x, you can use the following command:
    $ git clone git:// --branch v5.15.x
  2. Init Qt repository
    $ cd qt5
    $ ./init-repository --module-subset=qtbase
  3. Apply the wolfSSL Qt patch file to qt5.
    $ wget
    $ cd qtbase
    $ git apply -v ../wolfssl-qt-515.patch
  4. Configure Qt5
    $ cd ../../
    $ mkdir build
    $ cd ./build
    $ ../qt5/configure -opensource -wolfssl-linked -confirm-license -ccache -no-pch -developer-build -I/path/to/wolfssl-install/include/wolfssl -I/path/to/wolfssl-install/include
  5. Build Qt
    $ make

To find more detailed steps and then run test cases, you can find them in README at our ops repository.

If you have questions about any of the above, feel free to email us at or, or call us at +1 425 245 8247.

Download wolfSSL Now

cURL Up 2024 – Save The Date

Exciting news from cURL! We’re thrilled to announce the return of curl-up, scheduled to take place in Stockholm, Sweden from May 4th to the 5th! Our goal is to bring the community together for an unforgettable weekend of collaboration and learning.

We’re inviting all curl contributors, maintainers and fans to join us. Perfect opportunity for you to engage with Daniel Stenberg, the cURL founder, and maintainer of cURL, as well as other speakers and industry experts.

Save the date

  • Date: May 4th to the 5th
  • Location: Stockholm, Sweden

Stay updated on event details, including venue and agenda, on our dedicated web page, curl-up 2024. We’re open to agenda suggestions. Share your ideas on a curl mailing list or in the discussions section.

We would like to support our top-100 contributors with traveling and lodging expenses. Please read the funding attendance to see the regulation and eligibility requirements.

Registration is mandatory. Register now to secure your space! Let’s make curl-up 2024 an unforgettable weekend. See you there!

If you have questions about any of the above, please contact us at or call us at +1 425 245 9247.

Download wolfSSL Now

wolfSSL leading provider of cryptography and network security is leveraging wolfBoot in Avionic Systems

wolfSSL supports DO-178 secure boot on Intel’s 11th Gen Intel® Core™ Tiger Lake platform with TPM support and DO-178 certified artifacts.

EDMONDS, Wash., April 8, 2024 /PRNewswire-PRWeb/ — wolfSSL a leading provider of cryptography and network security is excited to share updates on new products and technology at Embedded World this April 9 – 11th in Nuremberg, Germany at Booth # 4-612.

wolfBoot in Avionic Systems:

wolfBoot, coupled with wolfCrypt cryptography library, offers a robust solution for avionic systems requiring DO-178C certification at specified Design Assurance Levels (DAL). This integration provides several advantages:

DO-178C Certification: wolfBoot can undergo the DO-178C certification process, meeting the stringent requirements for avionics applications. wolfSSL Inc. can provide the necessary certification evidence, ensuring compliance with aviation standards.

Code Optimization: wolfBoot allows for feature configuration and code tuning to minimize line count, thereby reducing costs and accelerating time to market. This optimization is crucial in avionics software development where efficiency and reliability are paramount.

Flexibility and Customizability: wolfBoot supports hardware-based cryptography and secure key storage solutions, including Intel-specific optimizations and TPM 2.0 modules. This flexibility enables integration with various hardware configurations and security architectures required in avionics systems.

Secure Boot Solutions: wolfBoot supports FIPS 140-2 or FIPS 140-3 validated cryptography for secure boot processes, ensuring firmware integrity and protection against malicious attacks during boot-up.

Acceleration on Intel Processors: Utilizing wolfCrypt on 11th Gen Intel Core processors offers significant performance enhancements. Intel AVX2 instructions accelerate SHA2 algorithms for verifying firmware integrity, while AES-NI instructions boost encryption and decryption operations for AES-encrypted firmware images.

Integration with Other Intel Security Features: With Intel’s emphasis on processor and platform security, there is potential for wolfBoot to extend its support for additional security features, leveraging Intel’s advancements in this domain.

The integration of wolfBoot and wolfCrypt on Intel processors provides a comprehensive solution for avionics. wolfBoot can meet all certification requirements, performance needs, and resource restrictions.

If you have questions about any of the above, please contact us at or call us at +1 425 245 8247.

Download wolfSSL Now

The New wolfSSL “Experimental” Framework

The experimental framework in wolfSSL includes several components aimed at enhancing its capabilities, particularly in the realm of post-quantum cryptography. Here are some key aspects of the framework:

  • XMSS Implementation: wolfSSL’s Extended Merkle Signature Scheme (XMSS) implementation is available upon request. It is a stateful hash-based cryptographic signature scheme
  • LMS Implementation: wolfSSL’s Leighton-Micali Signature (LMS) scheme is also available upon request. It is another stateful hash based signature scheme that provides security against quantum computer attacks.
  • Kyber Implementation: The framework includes an experimental implementation of the Kyber (AKA ML-KEM) algorithm, a post-quantum key encapsulation mechanism. This is coupled with assembly optimizations and is already included in wolfSSL; no need for special request!
  • Post-Quantum Dual Key/Signature Certificates: Support for dual algorithm certificates is part of the experimental features, which is crucial for transitioning to post-quantum cryptography.

These features are part of wolfSSL’s efforts to stay ahead in the security domain by incorporating next-generation cryptographic standards and preparing for the advent of quantum computing. For more detailed information or to access these experimental features, you can visit the wolfSSL GitHub repository or download wolfSSL release 5.7.0 or higher.

Note that while these features are a part of the experimental framework, backwards compatibility should not be expected. As features eventually move out of the experimental framework, that is when backwards compatibility and stability can be expected.

If you have questions about any of the above, please contact us at or call us at +1 425 245 8247.

Download wolfSSL Now

wolfSSL Inc. Unveils Cutting-Edge Cryptography and Network Security Solutions at Embedded World 2024

wolfSSL Inc. is a leading provider of cryptography and network security solutions, offering a comprehensive suite of products and services designed to secure embedded systems, IoT devices, and connected applications. With a commitment to innovation and excellence, wolfSSL empowers developers worldwide to build secure, scalable, and efficient solutions for the most demanding cybersecurity challenges.

EDMONDS, Wash., April 8, 2024 /PRNewswire-PRWeb/ — wolfSSL Inc. Unveils Cutting-Edge Cryptography and Network Security Solutions at Embedded World 2024

wolfSSL Inc., a globally renowned leader in cryptography and network security solutions, is thrilled to announce its participation at Embedded World 2024, scheduled to take place from April 9th to 11th in Nuremberg, Germany. The company will showcase its latest innovations and advancements in the realm of cybersecurity at Booth #4-612.

Embedded World serves as a premier platform for companies to unveil their latest technologies and engage with industry professionals, and wolfSSL is poised to make a significant impact with its array of groundbreaking products and services.

Among the highlights of wolfSSL’s showcase are:

  1. Kyber: A cutting-edge post quantum cryptographic algorithm designed for robust security in a variety of applications. As a Key Encapsulation Method Kyber ensures the security of symmetric key material.
  2. LMS (Leighton-Micali Signature): An innovative digital signature scheme offering enhanced security and efficiency. LMS is particularly valuable in today’s evolving cyber threat landscape due to its resilience against quantum computing threats.
  3. XMSS (eXtended Merkle Signature Scheme): A state-of-the-art digital signature scheme known for its resistance against quantum computing attacks, providing long-term security for critical systems.
  4. SM Ciphers: wolfCrypt now includes the Chinese SM variants of hashing, encryption, and digital signatures.
  5. CNSA 2.0 Support: wolfSSL demonstrates its commitment to staying ahead of evolving security standards by offering support for the latest Cryptographic Algorithm Validation Program (CAVP) requirements, including CNSA 2.0 cryptographic algorithms.
  6. DTLS 1.3: Datagram Transport Layer Security version 1.3, is the latest iteration of the DTLS protocol, which is based on the TLS (Transport Layer Security) protocol. It is designed to provide secure communication for datagram protocols, such as UDP (User Datagram Protocol). DTLS 1.3 brings several improvements over its predecessors, including enhanced security features, improved performance, and reduced latency. The latest version incorporates modern cryptographic algorithms and techniques, offering stronger protection against various security threats, while optimizing the protocol for better efficiency in real-world applications.
  7. wolfBoot: A secure bootloader solution designed to protect embedded systems from unauthorized access and tampering. wolfBoot ensures the integrity of the boot process against malicious attackers.
  8. wolfCrypt DO-178: A DO-178C certified cryptographic library, compliant with the rigorous safety standards required for avionics and other safety-critical systems.

“We are excited to showcase our latest innovations and technology offerings at Embedded World 2024,” said Larry Stefonic, CEO of wolfSSL Inc. “As a leading provider of cryptography and network security solutions, we are committed to empowering developers with the tools they need to build secure and resilient embedded systems. We look forward to engaging with attendees and demonstrating how our solutions can address the evolving cybersecurity challenges faced by industries worldwide.”

Visit wolfSSL at Booth #4-612 during Embedded World 2024 to learn more about their cutting-edge products and solutions, or visit for additional information.

If you have questions about any of the above, please contact us at or call us at +1 425 245 8247.

Download wolfSSL Now

Where to find the Wolves: wolfSSL is heading to Embedded World

Secure your Embedded Projects with wolfSSL, the Best Tested Cryptography.

The wolfSSL team is heading to Embedded World Exposition and Conference April 9th through the 11th in Nuremberg Germany.

Come stop by and meet our team at Hall 4 Booth 612.

Discover how wolfSSL’s advanced security solutions can safeguard your embedded development. If you prefer to set a specific time with our engineers, email us at

Protect your security assets by staying one step ahead of cyberattacks with wolfSSL’s cutting-edge cryptography. With over 2 billion connections secured, our partners trust in the best tested cryptography designed to safeguard embedded projects. Head over to to download our open source products.

Unmatched Efficiency for Resource-Constrained Devices

  • Lightweight and Portable: Written in C, wolfSSL boasts a compact footprint, 20x smaller than OpenSSL, minimizing memory usage and maximizing performance on even the most resource-constrained microcontrollers and processors. Integrate robust security into your embedded systems without sacrificing functionality or performance.
  • Reduced Power Consumption: Minimizes power consumption, making it ideal for battery-powered devices and applications where extending battery life is critical. View our benchmarks.

Streamlined Development & Integration

  • Simplified Development: wolfSSL provides documented and user-friendly API, allowing developers of all experiences to quickly and easily integrate secure communication into their projects.
  • OpenSSL Compatibility Layer: For those familiar with OpenSSL, wolfSSL offers a compatibility layer that simplifies the transition, reducing development time and effort.
  • Industry Leading Support: All of our products are backed with up to 24/7 support from our engineering team.
  • Winbond Hardware Security for Secure Firmware Updates: wolfSSL supports Level Metering Scheme (LMS) compatibility. This allows wolfSSL to work with Winbond hardware-based LMS to ensure the authenticity of a firmware image during over-the-air (OTA) updates for an IoT target device. An IoT device typically uses Winbond flash memory for storage and runs wolfSSL for security. With this compatibility, the device can verify the firmware update it receives is genuine and hasn’t been tampered with before installing it. This helps to protect the device from unauthorized modifications and potential security risks. Additionally, wolfSSL can provide the secure TLS or DTLS connection to the cloud and use wolfMQTT to manage the FW update. In combination with Winbond’s ongoing hardware crypto validation, wolfSSL can deliver FIPS 140-3 compliant solutions for customers demanding the highest security and compliance.

Futureproof Security for Advanced Threats

FIPS Compliance and Dual Licensing

  • FIPS 140-2 Certified wolfCrypt Module: For applications demanding the highest level security and regulatory compliance, wolfSSL offers the FIPS 140-2 certified wolfCrypt module.

Want to learn more information on our products?


Lightweight embedded SSL/TLS library written in ANSI C and targeted for embedded, RTOS, and resource-constrained environments – primarily because of its small size, speed, and feature set.

  • wolfSSL supports industry standards up to the current TLS 1.3 and DTLS 1.3 levels, and is up to 20 times smaller than OpenSSL.
  • Offers a simple API, OpenSSL compatibility layer, OCSP and CRL support, and offers several progressive ciphers.


Embedded Cryptography Engine

  • Lightweight crypto library written in ANSI C and targeted for embedded, RTOS, and resource-constrained environments.
  • Commonly used in standard operating environments as well due to royalty-free pricing and great cross platform support.
  • Supports algorithms and ciphers including ChaCha20, Curve25519, NTRU, and SHA-3.

wolfSSL Support for DO-178C DAL A

Enabling Secure Boot & Secure Firmware Update for Avionics

  • RTCA DO-178C level A certification.
  • wolfSSL offers DO-178 wolfCrypt as a commercial off-the-shelf (COTS) solution for connected avionics applications.
  • Adherence to DO-178C level A is supported through the first wolfCrypt COTS DO-178C certification kit release that includes traceable artifacts for the following encryption algorithms:
    • SHA-256 and SHA-384 for message digest.
    • AES for encryption and decryption.
    • RSA to sign and verify a message.
    • ChaCha20-Poly1305 for authenticated encryption and decryption.
    • ECC to sign, verify and share secrets.
    • HMAC for keyed-hashing for message authentication.
  • Provides the proper cryptographic underpinnings for secure boot and secure firmware update in commercial and military avionics.


TPM 2.0 designed for embedded use. wolfTPM is highly portable – written in native C, having a single IO callback for SPI hardware interface, no external dependencies, and its compacted code with low resource usage.

  • Open-source TPM 2.0 stack with backward API compatibility.
  • Native support for Linux & Windows.
  • RTOS and bare metal environments can use a single IO callback for SPI hardware interface, no external dependencies, and compact code size with low resource usage.
  • Offers API wrappers to help with complex TPM operations like attestation and examples to help with complex cryptographic processes like the generation of Certificate Signing Request (CSR) using a TPM.
  • Easy to compile on new platforms.


Client implementation of the MQTT written in C for embedded use.

  • Message Queuing Telemetry Transport is a lightweight open messaging protocol that was developed for constrained environments such as M2M (Machine to Machine) and IoT (Internet of Things), where a small code footprint is required.
  • Based on the Pub/Sub messaging principle of publishing messages and subscribing to topics.
  • The MQTT specification recommends TLS as a transport option to secure the protocol using port 8883 (secure-mqtt), as the MQTT protocol does not provide security on its own. Constrained devices benefit from using TLS session resumption to reduce the reconnection cost.
  • The wolfMQTT library is a client implementation of the MQTT written in C for embedded use. It supports SSL/TLS via the wolfSSL library. From this, it can provide the security that the MQTT protocol lacks.
  • Built from the ground up to be multi-platform, space conscious and extensible. Supports all Packet Types, all Quality of Service (QoS) levels 0-2 and supports SSL/TLS using the wolfSSL library. This implementation provides support for MQTT v5.0 and MQTT v3.1.1. Including client support for MQTT-SN (Sensor Network).


Lightweight SSHv2 server library written in ANSI C and targeted for embedded, RTOS, and resource-constrained environments – primarily because of its small size, speed, and feature set.

  • Commonly used in standard operating environments due to royalty-free pricing and excellent cross platform support.
  • wolfSSH is powered by the wolfCrypt library. A version of the wolfCrypt cryptography library has been FIPS 140-2 validated (Certificate #3389). For additional information, visit the wolfCrypt FIPS FAQ or contact


Secures the boot process of your device against malicious attacks that seek to replace your firmware and take control of your device, and/or steal its data.

  • Portable secure bootloader that offers firmware authentication and firmware update mechanisms. Due to its minimalistic design and tiny HAL API, wolfBoot is completely independent from any OS or bare-metal application.
  • Can be easily ported and integrated in existing embedded software projects to provide a secure firmware update mechanism.
  • Can be easily ported and integrated in existing embedded software projects to provide a secure firmware update mechanism.
  • Please email us at with any questions about Secure Boot.


A universal, dynamic, embedded IDPS (intrusion detection and prevention system)

  • Dynamic Firewall Engine: Analyzes network traffic for suspicious activity using static and dynamic rules.
  • User-defined Actions: Allows customization of responses to detected threats.
  • Integration with wolfSSL Products: Works seamlessly with wolfSSL libraries for a holistic security solution.
  • Zero-Configuration Option: Easy setup for developers.
  • Dynamic Configuration: Flexible control through API or text inputs.
  • Advanced Features (under development): Remote logging, configuration, and status queries.
  • Low Resource Footprint designed for Embedded Systems: Well-suited for RTOS, ARM processors, and other embedded devices.
  • Lightweight: Adds as little as 64k to code size and leverages existing application logic.

curl/tiny-curl Support

Computer software project providing a library for transferring data using various protocols.

wolfSSL JSSE Provider and JNI Wrapper

For Java applications that wish to leverage the industry-leading wolfSSL SSL/TLS implementation for secure communication.

wolfCrypt JNI and JCE Provider

For Java developers who want to leverage the industry-leading wolfCrypt cryptography library implementation, wolfCrypt JNI provides a Java interface to the native C library.


wolfSSL’s portable command line utility.

  • Handles common cryptographic operations, such as certificate parsing and key generation, for easier usage than writing an application from scratch.
  • Ideal for customers who want to do simple crypto operations without writing an application.

Let’s connect, get in contact with us today.

If you have questions about any of the above or would like to schedule a meeting with us, please contact us at or call us at +1 425 245 8247.

Download wolfSSL Now

Partner Webinar: Increased Cybersecurity Resiliency through System Architecture – Best Practices

We’re excited to announce our partner webinar with Lynx and RunSafe Security on “Increased Cybersecurity Resiliency through System Architecture – Best Practices” scheduled for April 10th at 9am PT. wolfSSL Software Engineer, Tesfa Mael, along with Dr. Justin Pearson, Director of System Architecture at Lynx, and Doug Britton, Chief Strategy Officer and Director at RunSafe Security will be leading the discussion.

Save the date: April 10th | 9am PT

In today’s landscape, where cyber threats against unmanned systems are escalating, the need to strengthen defenses has never been more pressing. With over 12,000 cyber incidents targeting unmanned systems recorded between 2015 and 2021, it’s clear that proactive measures are essential.

During this webinar, you’ll explore crucial topics such as:

  • Utilizing Open Source Safely: Learn how to leverage open-source technologies like Linux and containers securely to bolster your system’s resilience against cyber threats.
  • Validating System Components: Explore the importance of verifying hardware and software components to identify vulnerabilities and fortify your defense mechanisms.
  • Implementing Containment Strategies: Discover effective strategies to mitigate the impact of cyberattacks and unintentional breaches, minimizing potential damages and disruptions to your operations.

Don’t miss this invaluable opportunity to gain insights from industry experts and strengthen the cyber defenses of your organization. Secure your spot today while seats are available.

Our webinars always include Q&A sessions. If you have any questions about any of the above, please reach out to us at or call us at +1 425 245 8247.

Download wolfSSL Now

Post Quantum Key Share on the Espressif ESP32

Recently we announced that wolfSSL’s Kyber ML-KEM Implementation now Included free of charge for commercial customers. Our PQ Kyber implementation works on nearly any size of device, including the Espressif ESP32. Here are the instructions on configuring the test server and client:

ESP32 Server Application Settings

To enable Kyber, just add these lines to the user_settings.h file:

#define WOLFSSL_SHA3

Next, in the code after the creation of an ssl object:

ssl = wolfSSL_new(ctx));

Simply add this line:

wolfSSL_UseKeyShare(ssl, WOLFSSL_P521_KYBER_LEVEL5);

If successful, the function will return a code of SSL_SUCCESS.

The listening server needs a minimum stack size of approximately 10K bytes.

Linux Client Application Settings

To test with the wolfSSL client, configure wolfSSL to enable the experimental Kyber features:

 ./configure --enable-kyber=all --enable-experimental

Connect to the listening ESP32 server like this:

./examples/client/client -h -v 4 \
                         -l TLS_AES_128_GCM_SHA256 \
                         --pqc KYBER_LEVEL5

The resulting output should look like this:

Using Post-Quantum KEM: KYBER_LEVEL5
SSL version is TLSv1.3
SSL cipher suite is TLS_AES_128_GCM_SHA256
I hear you fa shizzle!

Linux Server Application Settings

To test with the wolfSSL client, configure wolfSSL as shown above for the client, and use this example:

./examples/server/server -v 4 \
                         -l TLS_AES_128_GCM_SHA256 
                         --pqc KYBER_LEVEL5

The TLS 1.3 server will quietly listen on port 11111. Upon a successful connection from a client, the resulting output should look something like this:

Using Post-Quantum KEM: KYBER_LEVEL5
SSL version is TLSv1.3
SSL cipher suite is TLS_AES_128_GCM_SHA256
Client message: hello wolfssl!

Keep in mind various local firewall rules may need to be adjusted to allow a port 11111 connection. How to determine if there’s a firewall issue? Check WireShark for TCP Retransmission packets that might look something like this:

Are you interested in trying our Post Quantum in your project? Let us know!

Find out more

If you have any feedback, questions, or require support, please don’t hesitate to reach out to us via, call us at +1 425 245 8247, or open an issue on GitHub.

Download wolfSSL Now

wolfBoot: secure boot and more | Unique features to assist and optimize firmware updates

Secure boot. Simple, compact, safe.

wolfBoot is the universal secure bootloader designed for embedded systems. Its main task is to ensure that only a trusted firmware image can run on the target device, as indicated by RFC9019. To do so, it uses signature verification on the firmware image every time the device starts or when a firmware update is received, OTA or through any custom transport.
wolfBoot relies on wolfCrypt cryptographic engine to support the widest range of
options for signature verification algorithms, including ECC-256, RSA up to 4096 bit, Ed25519 and Ed448, and up to post-quantum algorithms such as LMS/HSS and XMSS
Thanks to a wide choice of hardware security modules and crypto co-processors supported by wolfCrypt, wolfBoot can offload all cryptographic operations to dedicated hardware components when available, cutting down boot time and run-time resources.

Support for Post-quantum cryptography

wolfBoot’s support for Post-Quantum Cryptography (PQC) firmware authentication introduces a robust layer of security to embedded systems, ensuring resilience against emerging threats posed by quantum computing advancements. Leveraging schemes like Leighton-Micali Signature (LMS) with Hash-based Merkle Signature Scheme (HSS) or eXtended Merkle Signature Scheme (XMSS), as well as its multi-tree variant, XMSS^MT, wolfBoot secures its firmware authentication mechanism against potential quantum attacks. By integrating these advanced techniques into the bootloader, wolfBoot ensures the integrity of firmware updates for future-proof systems, against the constantly evolving cryptographic attacks.

Secure boot for all systems

wolfBoot does not depend on any specific libraries, except for wolfCrypt. It does not rely on any operating system environment, driver, platform or toolchains.
wolfBoot can secure the entire boot process of any standalone applications as well as complex operating systems, from small class-I microcontrollers up to Rich Execution Environments, on a wide range of microcontrollers and processors architectures (ARM, x86, PowerPc, RISC-V, x86 and more).
Native ports are available for the majority of common embedded targets and evaluation boards. In cases where a native port isn’t readily accessible, wolfSSL extends its engineering services to prioritize porting efforts, ensuring compatibility across virtually any platforms.

Key management tools

The key command line tools, ‘sign’ and ‘keygen’ (for Windows, Linux, MacOS), distributed along with wolfBoot, follow the development of all the features supported by the bootloader to the latest version. They are easy to use, widely documented, and simple to integrate with any deploy mechanism and back-end update services.

Retrofitting existing non-secure bootloaders

Already using your very own bootloader in your existing project? Do not worry. wolfBoot can be integrated with your current solution, by including one single .c file to your old bootloader code.
For existing bootloaders lacking support for secure boot, wolfBoot can in fact be effortlessly integrated as a library, exposing an API for verifying the authenticity and integrity of firmware. This integration enables the utilization of host tools for key management and firmware signing, leveraging the compatibility of wolfBoot’s manifest header for streamlined firmware update processes.

Roll-back: the bootloader “rescue” mode

wolfBoot stores a copy of the old firmware that gets replaced during the update. Mistakes can happen when building or transmitting a firmware update: even if the firmware is trusted and authenticated by wolfBoot it might still introduce bugs and issues in the field that may prevent the device from being reachable again. For this reason, wolfBoot implements a mechanism that requires the firmware to confirm that the system is working as expected after the update. In absence of this confirmation, at the next reboot wolfBoot considers the update as failed, and restores the original image from the backup taken during the update.

Use any external storage, with built-in confidentiality

Some microcontrollers may not have enough flash space to accommodate two versions of the firmware in the internal FLASH. The only requirement on these systems is normally that only the current executing firmware image should be stored in FLASH, where it can be eXecuted in Place (XiP). Most systems don’t support XiP on external storage supports, but that space can still be allocated to store updates and host the swap space required by wolfBoot to perform the update.

Thanks to a transparent, generic external flash interface, wolfBoot can use any external non-volatile memory support to host update and swap partitions, maximizing the space available in the internal FLASH for the running software.

Neighbor systems can host a virtual partition for the wolfBoot target, using any communication bus to implement remote, emulated memory access.

Encryption and decryption is done at runtime by wolfBoot when accessing these external storage devices for writing and reading, respectively. This mechanism prevents wiretapping or intercepting the firmware images when they are transferred on the BUS (SPI, CAN, Uart,…) that connects to the storage device.

Examples distributed with wolfBoot showcase this feature, with common SPI FLASH targets, and emulated remote storage, on a neighbor system via UART.

HSM support, wolfTPM integration, measured boot

wolfBoot inherits from wolfCrypt the capability to access hardware-assisted functionality offered by Hardware Security Modules (HSMs).

Through wolfTPM‘s integration, wolfBoot strengthens the security of firmware updates but also establishes a robust foundation for safeguarding critical assets and maintaining the trustworthiness of embedded systems. Through wolfTPM’s support, wolfBoot enables measured boot processes, ensuring the integrity of the entire boot chain and providing robust protection against tampering and unauthorized modifications of both hardware and software components. wolfTPM facilitates the implementation of advanced security policies, utilizing Platform Configuration Registers (PCRs) to unlock secrets and enforce access controls in accordance.

Self-update: can a secure bootloader update itself?

wolfBoot offers the possibility to authenticate and install a newer version of itself. A special update package can be created with the key tools, containing an update for the bootloader itself. wolfBoot will parse, authenticate and install the update by temporarily executing a copy of itself in RAM.

Incremental updates: faster OTA transfers with “delta updates”

wolfBoot supports incremental updates, based on a specific older version. Thesign tool can create a small “patch” that only contains the binary difference between the version currently running on target and the update package, a ‘delta update’ package. This package is processed by wolfBoot to reconstruct a complete image of the resulting update. The authenticity of the update is verified twice: first when the package is received before applying the patch, and then after the patch is applied, every time the new firmware is staged for boot.

Where has wolfBoot been ported so far?

  • STM32: nearly all models (STM32C0, STM32F0, STM32G0, STM32L0, STM32F4, STM32L4, STM32L5, STM32H5, STM32H7, STM32U5, STM32WB)
  • NXP: LPC54xxx, i.MX-RT10xx, K64F, K83F, MCXA, P1020, T1024, T2080
  • Microchip: SAM R21, SAM E51, PSoC6
  • Renesas: RA6M4, RX72N, RZN2L
  • Nordic: nRF52
  • TI “Hercules” TMS570
  • SiFive: HiFive1 RISCV RV32 microcontroller
  • Cortex-A Microprocessors: Xilinx Ultrascale Zynq+, Raspberry PI
  • x86_64bit: as UEFI application
  • x86_64 Intel Tigerlake: native BIOS replacement using Intel FSP

Porting wolfBoot to a new target is easy. Our HAL API consists of only six mandatory functions to be implemented to perform target-specific clock initialization and interact with the non-volatile memory containing the signed software images.

What feature would you like to see in the next release of wolfBoot? Contact us at with any comments or questions!

Check out our GitHub page for the full documentation, and to stay up to date with our latest developments. And while you are there, consider giving the wolfBoot project a star!

If you have questions about any of the above, please contact us at or call us at +1 425 245 8247

Download wolfSSL Now

What does wolfSSL do to mitigate against attacks similar to the xz/liblzma malware in OpenSSH?

A recent backdoor breach in Debian SSH connections, facilitated by an adversarial code contribution to the xz/liblzma project[1], underscores the need for rigorous vetting of code, contributors and intent. wolfSSL Inc. implements stringent procedures to prevent scenarios like malicious code merges.

For non-employee code contributors:

  • An authorized wolfSSL Inc. employee provides written acceptance to evaluate proposed code changes, signaling to other employees that the changes have been vetted for suspect code patterns and desirable content is present in the proposal
  • wolfSSL Inc. conducts a legal review of contributors’ signed agreements and approval history, considering factors such as organizational changes and the ongoing justification for contribution irrespective of desirable content.
  • wolfSSL Inc requires a written explanation from the author summarizing the benefits of the proposed change and project involvement justifying the proposal.
  • Prior to code merge, all continuous integration tests must pass, including static and dynamic analysis. Performance and resource criteria must also be met, confirming no significant negative impact on throughput, performance, or binary object size.
  • Prior to code merge, and in addition to the first authority approval, 1-4 wolfSSL Inc employees must review the code for final approval. Unreviewed code is never merged.

Internally, code changes from employees are also thoroughly vetted, including an identical code review process:

  • wolfSSL Inc requires a written explanation from the employee author summarizing the benefits of the proposed change.
  • Prior to code merge, all continuous integration tests must pass, including static and dynamic analysis and performance criteria.
  • Prior to code merge, 1-3 additional wolfSSL Inc employees must review the code for final approval. Unreviewed code is never merged.

On a daily basis, all code is subjected to extensive offline analysis, targeting a wide variety of systems and configurations. Historical, current, and prerelease toolchains and analyzers are used in vetting. Before tagging a release, wolfSSL has a policy of zero reported defects from the continuously updating and expanding mainline automated analysis suite.

These processes exemplify wolfSSL Inc.’s commitment to safeguarding source code against malicious backdoor introductions, and other suspect code patterns, intentional or otherwise.



If you have questions about any of the above, please contact us at or call us at +1 425 245 8247.

Download wolfSSL Now

Posts navigation

1 2 3 4 5 6 7 8 190 191 192

Weekly updates