Linux kernel developers are moving forward with plans to remove the crypto_rng API layer, a long-standing component of the kernel's cryptographic subsystem. The proposed change is part of a broader effort to simplify the kernel's internal architecture by eliminating redundant code paths and encouraging developers to rely on the kernel's modern random number generation interfaces instead. (phoronix.com)

Although the change happens entirely behind the scenes, it reflects the Linux kernel community's ongoing commitment to reducing technical debt, improving maintainability, and modernizing core infrastructure.

What Is the crypto_rng Layer?

The crypto_rng framework is an API within the Linux kernel's Crypto API that provides random number generation services for kernel components.

Historically, it allowed different kernel subsystems and drivers to request random data through a generic cryptographic interface. Over time, however, the kernel's dedicated random number generator has matured considerably, making much of the crypto_rng abstraction unnecessary. (kernel.org)

Today, developers generally recommend using the kernel's built-in random number generation functions directly instead of routing requests through the older crypto layer.

Why Developers Want to Remove It

According to discussions on the Linux kernel mailing list, the crypto_rng layer has become largely redundant.

Modern kernel code already relies on well-established interfaces such as:

• get_random_bytes()
• get_random_u32()
• get_random_u64()

These functions are maintained as part of the kernel's primary random number generation subsystem and are widely used throughout Linux. Maintaining an additional abstraction layer increases code complexity without providing significant practical benefits. (phoronix.com)

Removing unnecessary infrastructure also makes the kernel easier to maintain and audit over the long term.

Simplifying the Crypto API

The Linux Crypto API has evolved significantly over the years as new algorithms, hardware accelerators, and security features have been introduced.

Kernel maintainers have increasingly focused on:

• Removing obsolete interfaces
• Reducing duplicated functionality
• Simplifying internal APIs
• Improving long-term maintainability
• Making the codebase easier for new contributors to understand

The proposed removal of crypto_rng fits squarely within that broader cleanup effort. (kernel.org)

No Impact on Everyday Linux Users

For desktop and server users, the removal of the crypto_rng layer is expected to be almost entirely invisible.

Applications running in user space do not interact with this API directly. Instead, they typically obtain random data through standard system interfaces such as:

• /dev/urandom
• getrandom()
• Cryptographic libraries like OpenSSL or GnuTLS

Those interfaces remain unchanged, meaning software behavior should not be affected by the internal kernel cleanup.

Benefits for Kernel Developers

Although users are unlikely to notice any immediate difference, kernel developers stand to gain several advantages.

Removing an outdated API can help:

• Reduce maintenance overhead
• Eliminate duplicate implementations
• Simplify future kernel development
• Improve code readability
• Reduce the number of internal interfaces requiring long-term support

As Linux continues growing, periodic cleanup efforts like this help prevent unnecessary complexity from accumulating over time.

Part of a Larger Modernization Effort

The proposal is one example of a broader trend within Linux kernel development.

Recent kernel cycles have included efforts to:

• Remove legacy hardware support
• Simplify aging subsystems
• Improve memory management
• Modernize filesystem code
• Expand Rust infrastructure
• Refine security frameworks

Rather than continually adding new features without removing old ones, kernel developers increasingly emphasize keeping the codebase manageable and maintainable.

Security Remains a Priority

The planned removal of crypto_rng should not be interpreted as weakening Linux's cryptographic capabilities.

The kernel's primary random number generator has received years of development and security review. It remains the recommended source of cryptographically secure random numbers for kernel components, and removing redundant APIs can actually reduce potential maintenance and security risks by concentrating development on a single, well-supported implementation. (kernel.org)

When Will the Change Happen?

At this stage, the proposal is under review by Linux kernel maintainers. If accepted, the removal will likely take place during a future merge window after remaining users of the crypto_rng API have been converted to the newer interfaces. As with most kernel cleanups, the transition is expected to happen gradually to avoid disrupting existing code. (phoronix.com)

Conclusion

The Linux kernel's move toward removing the crypto_rng layer is another example of the project's ongoing effort to streamline its internal architecture. By retiring an API that has largely been superseded by modern random number generation interfaces, developers can reduce complexity, improve maintainability, and focus future work on a smaller, more robust set of core components.

While the change is unlikely to be noticeable for everyday Linux users, it represents the kind of behind-the-scenes engineering that helps keep the Linux kernel secure, efficient, and sustainable as it continues to evolve.