When developing Windows applications – for example, using Lazarus (Free Pascal) – OpenSSL is often required for encrypted network connections. As Windows does not include these libraries by default, the relevant DLL files must be supplied with the application.
For my own projects, I have compiled a selection of frequently required OpenSSL files and am making them available for download here.
Contents of the package
The collection contains files from various OpenSSL branches, as different libraries are required depending on the age of the project or the components used:
OpenSSL 3.x (64-bit)
These files are required by many newer 64-bit applications and modern HTTP clients:
libcrypto-3-x64.dlllibssl-3-x64.dlllibcrypto.dll(is looked for by some frameworks under this generic name)
OpenSSL 1.1.x (64-bit)
Used by many applications and components that have not yet transitioned to the newer 3.x branch:
libcrypto-1_1-x64.dlllibssl-1_1-x64.dll
Older OpenSSL versions (v1.0.x)
These files are frequently required by older projects or older network components (such as certain versions of Indy or Synapse):
libeay32.dllssleay32.dll
Usage
In practice, it is usually safest to copy the required DLL files directly into the directory of the executable application (next to the .exe). This ensures that the application remains portable and uses exactly the versions with which it was tested.
Security Note
The older files (ssleay32.dll and libeay32.dll) date from 2018. They no longer meet current security standards and should, where possible, only be used to maintain compatibility with existing legacy systems. For new or security-critical projects, we recommend using the OpenSSL 3.x branch.