64 stable releases

Uses old Rust 2015

300.1.5+3.1.3 Sep 19, 2023
300.1.3+3.1.2 Aug 2, 2023
300.1.2+3.1.1 May 31, 2023
300.1.0+3.1.0 Mar 29, 2023
110.0.1+1.1.0f Sep 15, 2017

#86 in Filesystem

Download history 136368/week @ 2023-06-08 138911/week @ 2023-06-15 136735/week @ 2023-06-22 124084/week @ 2023-06-29 138771/week @ 2023-07-06 130932/week @ 2023-07-13 141586/week @ 2023-07-20 135194/week @ 2023-07-27 155456/week @ 2023-08-03 144342/week @ 2023-08-10 151653/week @ 2023-08-17 163978/week @ 2023-08-24 152531/week @ 2023-08-31 166590/week @ 2023-09-07 173528/week @ 2023-09-14 169907/week @ 2023-09-21

696,088 downloads per month
Used in 969 crates (5 directly)


634K SLoC

C 426K SLoC // 0.1% comments Perl 199K SLoC // 0.1% comments GNU Style Assembly 6.5K SLoC // 0.1% comments Shell 1.5K SLoC // 0.2% comments Prolog 644 SLoC Rust 497 SLoC // 0.2% comments Assembly 311 SLoC // 0.1% comments ASN.1 136 SLoC // 0.5% comments Emacs Lisp 35 SLoC // 0.5% comments Python 29 SLoC // 0.3% comments Ruby 14 SLoC // 0.3% comments


This crate contains the logic to build OpenSSL and is intended to be consumed by the openssl-sys crate. You likely in theory aren't interacting with this too much!


This crate follows the latest minor and patch versions for each maintained major version, according to the OpenSSL release strategy. It has no specific support for LTS versions.

The crate versions follow the X.Y.Z+B pattern:

  • The major version X is the upstream OpenSSL API/ABI compatibility version:
    • 300 for 3.Y.Z
  • The minor Y and patch Z versions are incremented when making changes to the crate, either OpenSSL update or internal changes.
  • B contains the full upstream OpenSSL version, like 1.1.1k or 3.0.7. Note that this field is actually ignored in comparisons and only there for documentation.

Windows MSVC Assembly

Building OpenSSL for windows-msvc targets, users can choose whether to enable assembly language routines, which requires nasm.
The build process will automatically detect whether nasm.exe is installed in PATH. If found, the assembly language routines will be enabled (in other words, the no-asm option will NOT be configured).

You can manipulate this behavior by setting the OPENSSL_RUST_USE_NASM environment variable:

  • 1: Force enable the assembly language routines. (panic if nasm.exe is not available.)
  • 0: Force disable the assembly language routines even if the nasm.exe can be found in PATH.
  • not set: Let the build process automatically detect whether nasm.exe is installed. If found, enable. If not, disable.

However, this environment variable does NOT take effects on non-windows platforms.


This project is licensed under either of

at your option.


Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in openssl-src by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.