diff --git a/README.md b/README.md
index d89361e..d0445ef 100644
--- a/README.md
+++ b/README.md
@@ -76,6 +76,16 @@ In the `config/config.ini` file, configure the `PDF_STORAGE_PATH` variable with
 PDF_STORAGE_PATH=/path/to/folder
 ```
 
+You can enable PDFs to be stored encrypted on the server with a symmetric key known only to the signers.
+
+To activate it, gpg needs to be installed and option PDF_STORAGE_ENCRYPTION must be set to true.
+
+In the `config/config.ini` file :
+
+```
+PDF_STORAGE_ENCRYPTION=true
+```
+
 Create this folder:
 
 ```