diff --git a/lib/webrick/ssl.rb b/lib/webrick/ssl.rb
index d125083528..ab1837fda6 100644
--- a/lib/webrick/ssl.rb
+++ b/lib/webrick/ssl.rb
@@ -122,7 +122,7 @@ module WEBrick
       ef.issuer_certificate = cert
       cert.extensions = [
         ef.create_extension("basicConstraints","CA:FALSE"),
-        ef.create_extension("keyUsage", "keyEncipherment"),
+        ef.create_extension("keyUsage", "keyEncipherment, digitalSignature, keyAgreement, dataEncipherment"),
         ef.create_extension("subjectKeyIdentifier", "hash"),
         ef.create_extension("extendedKeyUsage", "serverAuth"),
         ef.create_extension("nsComment", comment),