diff --git a/scorm_engine.gemspec b/scorm_engine.gemspec
index 589b576..b17a689 100644
--- a/scorm_engine.gemspec
+++ b/scorm_engine.gemspec
@@ -20,6 +20,7 @@ Gem::Specification.new do |spec|
   spec.require_paths = ["lib"]
   spec.required_ruby_version = ">= 2.7"
 
+  spec.add_dependency "base64"
   spec.add_dependency "faraday", ">=0.12", "<=3.0"
   spec.add_dependency "faraday_middleware", ">=0.12", "<=2.0"