diff --git a/.gitignore b/.gitignore
index 09b424f..c1345c2 100644
--- a/.gitignore
+++ b/.gitignore
@@ -10,3 +10,6 @@
 # The binary.
 chasquid
 
+# Exclude any .pem files, to prevent accidentally including test keys and
+# certificates.
+*.pem