diff --git a/docs/BUILD_EXT.md b/docs/BUILD_EXT.md
index 85698d4f03..1ea1db320e 100644
--- a/docs/BUILD_EXT.md
+++ b/docs/BUILD_EXT.md
@@ -88,6 +88,7 @@ cd vcpkg
 .\vcpkg install openblas:x64-windows
 .\vcpkg install hdf5:x64-windows
 .\vcpkg install opencv4[core,jpeg,png,tiff,webp]:x64-windows
+.\vcpkg install cryptopp:x64-windows
 ```
 
 > Notice that you must install the `English Pack` for VS2019 for vcpkg to work. This can be done by clicking the `Language` panel in the VS2019 installer. (JOKE: the maintainer of vcpkg speaks Chinese too..)