OpenSSL vs. LibreSSL: A Comprehensive Comparison of History, Security, and Performance


Page content


OpenSSL and LibreSSL are two popular open-source cryptographic libraries that provide essential security features for various applications and protocols. While both libraries serve a similar purpose, they differ in their origins, philosophies, and approaches to security. In this article, we will explore the history, security, and performance aspects of OpenSSL and LibreSSL, shedding light on their similarities and differences.

OpenSSL and LibreSSL History


OpenSSL is a widely adopted and mature cryptographic library that originated in 1998 as a fork of the SSLeay library. It has played a significant role in securing numerous internet protocols and applications, including HTTPS, TLS, and SSL. OpenSSL’s development and maintenance are primarily handled by the OpenSSL Software Foundation, a volunteer-driven community that has faced several challenges and security vulnerabilities throughout its history.


LibreSSL, on the other hand, is a relatively newer project that emerged in 2014 as a fork of OpenSSL. It was born out of the need to address several security flaws and design issues found in OpenSSL, particularly the notorious Heartbleed vulnerability. LibreSSL aimed to provide a more secure and simplified version of the OpenSSL library, focusing on clean code, modernization, and improved security practices.

LibreSSL is primarily supported by the OpenBSD community, which played a significant role in its development and continues to maintain and enhance the library. The OpenBSD project, known for its commitment to security and code correctness, provides resources, infrastructure, and expertise to support the ongoing development of LibreSSL.

In addition to the OpenBSD community, LibreSSL has garnered support from various individuals, developers, and organizations that value its focus on security and simplicity. These supporters contribute to the project through code contributions, bug reports, security audits, and other forms of collaboration. The LibreSSL development team also welcomes feedback and contributions from the wider open-source community.

OpenSSL vs LibreSSL Security Comparision


OpenSSL has encountered notable security issues over the years, with the Heartbleed vulnerability being a major turning point. However, the OpenSSL community has made significant efforts to enhance security, introducing regular security audits, bug bounty programs, and more proactive vulnerability management. While it has faced challenges, OpenSSL remains widely trusted and actively used in numerous applications and systems worldwide.


LibreSSL took a proactive approach to address OpenSSL’s security challenges by conducting an extensive code audit and removing outdated and vulnerable code. It also adopted a policy of keeping the codebase simple and focused on security. LibreSSL’s developers prioritize proactive security practices, timely vulnerability patching, and code clarity to minimize the potential for security flaws. This emphasis on security has earned it a reputation as a reliable alternative to OpenSSL.

OpenSSL vs LibreSSL Performance Comparision


Due to its extensive use and long-standing presence, OpenSSL has received significant optimization efforts over the years. It benefits from a broad developer community and extensive compatibility with various platforms, making it highly performant. OpenSSL supports hardware acceleration and offers a wide range of cryptographic algorithms, allowing for flexibility and performance optimization in different scenarios.


LibreSSL has made performance improvements by removing outdated and unnecessary code from OpenSSL. By focusing on simplicity and clean design, LibreSSL aims to provide an efficient and lightweight library. While it may not offer the same breadth of platform support or feature set as OpenSSL, LibreSSL’s streamlined codebase can result in improved performance, especially for resource-constrained environments.

The following is a list of some notable code that was removed from OpenSSL when LibreSSL was forked:

  1. SSLv2 Support: LibreSSL removed support for SSLv2, an outdated and insecure protocol that has been widely deprecated due to significant security vulnerabilities.

  2. Heartbeat Extension: The Heartbeat Extension, which was responsible for the Heartbleed vulnerability in OpenSSL, was removed from LibreSSL. This vulnerability allowed an attacker to read sensitive information from the memory of a vulnerable server.

  3. Deprecated and Unused Code: LibreSSL eliminated various deprecated and unused code, including outdated cryptographic algorithms, unused functions, and obsolete code that was no longer relevant or considered secure.

  4. Complex Build System: The build system in OpenSSL was known to be complex and difficult to maintain. LibreSSL simplified the build process, removing unnecessary complexity and making it easier to compile and use the library.

  5. Old Platforms and Architectures: LibreSSL dropped support for outdated platforms and architectures that were no longer actively maintained or widely used. This allowed for a more focused development effort and better utilization of resources.

  6. Windows Support: Initially, LibreSSL did not provide official support for Windows, as the focus was primarily on Unix-like systems. However, efforts have been made to improve Windows compatibility, and Windows support has been added in subsequent versions.

It’s important to note that this list is not exhaustive and represents only a subset of the changes made in LibreSSL. The developers of LibreSSL have continuously worked to remove code that was deemed unnecessary, deprecated, or insecure, resulting in a cleaner and more secure codebase.

Which Organizations Using LibreSSL?

LibreSSL is used by a variety of organizations and projects that prioritize security and simplicity in their cryptographic implementations. Here are a few examples of entities known to use LibreSSL:

  1. OpenBSD: LibreSSL was initially developed as a replacement for OpenSSL in the OpenBSD operating system. OpenBSD has been one of the main driving forces behind LibreSSL and has integrated it as the default cryptographic library in its releases.

  2. OpenSSH: OpenSSH, a widely used implementation of the Secure Shell (SSH) protocol, has adopted LibreSSL as its default cryptographic library. This includes both the client and server components of OpenSSH.

  3. FreeBSD: While FreeBSD primarily uses OpenSSL as its default cryptographic library, it has provided support for LibreSSL as an alternative. This allows FreeBSD users to choose between the two libraries based on their specific needs and preferences.

  4. WolfSSL: WolfSSL, a lightweight and embeddable SSL/TLS library, has added support for LibreSSL alongside its existing support for OpenSSL. This provides developers using WolfSSL with the option to use LibreSSL as an alternative cryptographic library.

  5. Various Open Source Projects: Several open-source projects have chosen to use LibreSSL as their preferred cryptographic library due to its focus on security, simplicity, and clean code. Examples include OpenSMTPD, LibreNMS, and mg (Micro GNU Emacs).

It’s worth noting that while LibreSSL has gained popularity and adoption within certain communities, OpenSSL still remains the more widely used cryptographic library across a wide range of platforms, applications, and industries. The choice between OpenSSL and LibreSSL often depends on specific project requirements, risk assessments, and the need for additional security measures.

LibreSSL Advantages Compare to OpenSSL

LibreSSL offers several advantages when compared to OpenSSL:

  1. Enhanced Security: LibreSSL was created with a focus on security improvements. It underwent an extensive code audit, removing outdated and vulnerable code, and adopting proactive security practices. By prioritizing simplicity and clean code, LibreSSL aims to minimize potential security flaws and reduce attack vectors.

  2. Simplified Codebase: LibreSSL aims to provide a cleaner and more manageable codebase compared to OpenSSL. By removing deprecated, unused, and unnecessary code, LibreSSL streamlines the library, making it easier to understand, maintain, and audit. The simplified codebase reduces the risk of hidden vulnerabilities and makes it more accessible for developers to work with.

  3. Modernization: LibreSSL introduces modernization efforts, utilizing new programming practices and addressing design flaws found in OpenSSL. This includes removing support for outdated protocols, such as SSLv2, which are known to have significant security vulnerabilities.

  4. Proactive Development: The LibreSSL project emphasizes timely vulnerability patching and proactive development practices. It aims to quickly address security issues and release updates, ensuring that users have access to the latest security enhancements and bug fixes.

  5. Lightweight and Efficient: With its streamlined codebase and focus on simplicity, LibreSSL is designed to be lightweight and efficient. This can lead to improved performance, especially in resource-constrained environments or scenarios where efficiency is critical.

  6. OpenBSD Integration: LibreSSL has strong integration with the OpenBSD operating system, which has a reputation for its emphasis on security. This integration allows LibreSSL to benefit from OpenBSD’s rigorous development processes, security audits, and testing.

LibreSSL Disadvantages Compare to OpenSSL

While LibreSSL brings several advantages, it is important to consider its potential disadvantages when compared to OpenSSL:

  1. Limited Platform Support: LibreSSL initially focused primarily on Unix-like systems, which led to a lack of official support for certain platforms, such as Windows. Although efforts have been made to improve Windows compatibility in subsequent versions, it may still have limitations compared to the broad platform support of OpenSSL.

  2. Smaller Ecosystem and Community: OpenSSL has a larger and more established ecosystem and community compared to LibreSSL. This means that OpenSSL benefits from extensive third-party support, documentation, and community-driven development, resulting in a broader range of resources available for developers.

  3. Compatibility Challenges: Due to the code changes and removal of certain features, LibreSSL may face compatibility challenges with applications or systems originally designed to work with OpenSSL. This could potentially require modifications or updates to ensure proper integration with LibreSSL.

  4. Reduced Feature Set: LibreSSL, in its focus on simplicity and security, may have a reduced feature set compared to OpenSSL. While this streamlined approach can be an advantage in terms of code cleanliness and security, it may not offer the same breadth of options and flexibility as OpenSSL, particularly for specialized use cases.

  5. Potential Lag in Adoption: Despite its security improvements and streamlined design, LibreSSL has not achieved the same level of widespread adoption as OpenSSL. This may result in slower updates, a smaller developer community, and potential delays in addressing new vulnerabilities or adding new features.

OpenSSL vs LibreSSL Conclusion

Both OpenSSL and LibreSSL have their unique histories, philosophies, and areas of focus. OpenSSL’s maturity, extensive use, and broad compatibility make it a reliable choice for many applications. On the other hand, LibreSSL’s proactive security practices, clean codebase, and simplified design offer an appealing alternative for those seeking enhanced security and efficiency. Ultimately, the choice between OpenSSL and LibreSSL depends on the specific requirements, preferences, and risk profiles of the project at hand. Evaluating factors such as security, performance, community support, and compatibility will guide developers in making an informed decision for their cryptographic needs.

Related pages: