Jonathan Protzenko announced the release of Evercrypt 1.0 for Python, providing a high-assurance cryptography library with over 15,000 lines of formally verified code. This release leverages the HACL* cryptographic library, which has been mathematically proven correct, and makes it readily available for Python developers through a simple and performant interface. Evercrypt aims to bring robust, verified cryptographic primitives to a wider audience, improving security and trustworthiness for applications that depend on strong cryptography. It offers a drop-in replacement for existing libraries, significantly enhancing the security guarantees without requiring extensive code changes.
Jonathan Protzenko's blog post, "15,000 lines of verified cryptography now in Python," announces the significant achievement of integrating a substantial body of formally verified cryptographic code into the Python ecosystem. This endeavor, driven by the need for robust and provably secure cryptographic implementations, leverages the Evercrypt cryptographic provider, known for its high assurance and performance, and makes it readily accessible to Python developers.
Evercrypt itself is written in Low, a subset of the F programming language designed for high-performance cryptographic implementations. The core of Evercrypt's verification lies in formal proofs, mathematical guarantees that the code adheres to its specifications and is free from certain classes of vulnerabilities. These proofs, checked by a computer, provide significantly stronger assurances than traditional testing methodologies. However, directly using Low code within Python isn't feasible. Therefore, the project involved generating C code from the verified Low implementation, a process facilitated by the KreMLin code generation tool. This resulting C code inherits the security properties of the original Low* code.
To bridge the gap between the C code and Python, the project employs CFFI, a foreign function interface library for Python. CFFI enables Python code to interact seamlessly with C libraries, effectively exposing the underlying Evercrypt functionality to Python developers. This integration allows Python programmers to leverage Evercrypt's high-assurance cryptographic primitives without needing to write or understand C code.
The post highlights the practical implications of this work. It emphasizes that the 15,000 lines of verified cryptographic code now accessible in Python cover a wide range of cryptographic functionalities. This includes symmetric encryption algorithms like AES and ChaCha20-Poly1305, authenticated encryption with associated data (AEAD) schemes, hash functions such as SHA2 and SHA3, and digital signature algorithms like RSA-PSS and Ed25519. The availability of these verified implementations directly within Python significantly reduces the risk of introducing cryptographic vulnerabilities in Python applications, particularly in security-sensitive contexts.
Furthermore, the post underscores the performance benefits of using Evercrypt. The careful design and optimization of the underlying Low* code, coupled with efficient C bindings, result in performance comparable to, and in some cases exceeding, existing hand-optimized cryptographic libraries in Python. This performance characteristic makes the integration of Evercrypt appealing not only for its security properties but also for its efficiency.
In summary, the integration of Evercrypt into Python represents a major step towards improving the security and reliability of cryptographic operations in the Python ecosystem. By making formally verified cryptographic primitives readily available, this work empowers Python developers to build more secure applications without sacrificing performance.
Summary of Comments ( 130 )
https://news.ycombinator.com/item?id=43731165
Hacker News users discussed the implications of having 15,000 lines of verified cryptography in Python, focusing on the trade-offs between verification and performance. Some expressed skepticism about the practical benefits of formal verification for cryptographic libraries, citing the difficulty of verifying real-world usage and the potential performance overhead. Others emphasized the importance of correctness in cryptography, arguing that verification offers valuable guarantees despite its limitations. The performance costs were debated, with some suggesting that the overhead might be acceptable or even negligible in certain scenarios. Several commenters also discussed the challenges of formal verification in general, including the expertise required and the limitations of existing tools. The choice of Python was also questioned, with some suggesting that a language like OCaml might be more suitable for this type of project.
The Hacker News post titled "15,000 lines of verified cryptography now in Python" (https://news.ycombinator.com/item?id=43731165) sparked a discussion with several insightful comments.
Many commenters expressed enthusiasm for the project, highlighting the importance of verifiable cryptography and the potential benefits of its Python implementation. The accessibility of Python was seen as a key advantage, making this formally verified cryptography more readily available to a wider audience of developers.
A prevalent theme in the discussion revolved around the practicality and performance implications of using verified code in real-world applications. Some users questioned the runtime performance overhead, expressing concerns about the feasibility of using such libraries in performance-sensitive scenarios. Others countered this, arguing that the security benefits might outweigh the potential performance trade-offs, particularly in high-security applications.
Several commenters delved into the technical details of the project, discussing the use of the F* language and its role in the verification process. The challenges of integrating formally verified code with existing Python ecosystems were also mentioned.
Some users raised concerns about the limited scope of the current implementation, noting that 15,000 lines of code represent only a fraction of a complete cryptographic library. However, the author's response clarified that the current focus was on core cryptographic primitives, with plans for future expansion.
The discussion also touched on the broader implications of formal verification in software development. Commenters acknowledged the difficulty and cost of formal verification but also emphasized its potential to significantly enhance software security and reliability.
While generally positive, the comments also expressed a degree of cautious optimism. The novelty and complexity of the project mean its long-term success and adoption remain to be seen. Some users pointed out the need for thorough testing and real-world evaluation to fully assess the project's viability.