What is OpenSSL?

It is an open-source library that provides the processing necessary for encrypted communication.

To use it from a program, since the C language source code is public, you need to build it and create a library.

Below, we will introduce the build procedure.

Preparing the build environment

• Perl

  Download strawberry-perl-5.32.1.1-64bit.msi from https://strawberryperl.com/. The latest version should be fine.

• NASM

  Download 2.16.01/nasm-2.16.01-win64.zip from Download at https://www.nasm.us/. The latest non-rc version should be fine. After installation, you need to add the folder where NASM was installed to the environment variable PATH.

• Visual Studio 2022 ** or ** Build Tools for Visual Studio 2022

  Install Visual Studio 2022 Community or Build Tools for Visual Studio 2022 from https://visualstudio.microsoft.com/ja/downloads/.

OpenSSL build procedure on Windows

1. Download and extract openssl-3.1.0.tar.gz from https://www.openssl.org/source/. If you cannot extract it, execute tar -xzf openssl-3.1.0.tar.gz in the command prompt.
2. Launch the command prompt with administrator privileges.
3. Open the extracted folder.
4. Execute the following command *Change the Community part according to the version of Visual Studio you installed

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"C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Auxiliary\Build\vcvarsall.bat" x64

5. Execute the following command

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perl Configure VC-WIN64A

6. Execute the following command (takes a considerable amount of time)

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nmake

7. Execute the following command (takes a considerable amount of time)

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nmake test

8. Execute the following command

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nmake install

If successful, OpenSSL will be installed in C:\Program Files\OpenSSL.

That is all.

Reference

https://ja.wikipedia.org/wiki/OpenSSL