diff --git a/lib/passkit/generator.rb b/lib/passkit/generator.rb
index 80b5304..596a8b1 100644
--- a/lib/passkit/generator.rb
+++ b/lib/passkit/generator.rb
@@ -96,6 +96,9 @@ def generate_json_manifest
 
     # :nocov:
     def sign_manifest
+      OpenSSL::Provider.load("default")
+      OpenSSL::Provider.load("legacy")
+
       p12_certificate = OpenSSL::PKCS12.new(File.read(CERTIFICATE), CERTIFICATE_PASSWORD)
       intermediate_certificate = OpenSSL::X509::Certificate.new(File.read(INTERMEDIATE_CERTIFICATE))