is a Windows DLL that provides OpenSSL's libcrypto functionality built for Cygwin or similar POSIX-on-Windows environments. In 2021 it appeared across a range of contexts: legacy builds, third‑party bundled OpenSSL libraries, malware analysis reports, and troubleshooting threads where missing or mismatched cygcrypto DLLs caused application failures.

This migration caused a naming shift:

The Cygcrypto11.dll 2021 error can occur due to various reasons, including: