diff --git a/lib/openssl/digest.rb b/lib/openssl/digest.rb
index 46ddfd602..4e6dea8d0 100644
--- a/lib/openssl/digest.rb
+++ b/lib/openssl/digest.rb
@@ -27,17 +27,21 @@ def self.digest(name, data)
     end
 
     %w(MD4 MD5 RIPEMD160 SHA1 SHA224 SHA256 SHA384 SHA512).each do |name|
-      klass = Class.new(self) {
-        define_method(:initialize, ->(data = nil) {super(name, data)})
-      }
-
-      singleton = (class << klass; self; end)
-
-      singleton.class_eval{
-        define_method(:digest) {|data| new.digest(data)}
-        define_method(:hexdigest) {|data| new.hexdigest(data)}
-      }
+      klass = Class.new(self)
+      klass.class_eval <<-RUBY, __FILE__, __LINE__ + 1
+        def initialize(data = nil)
+          super("#{name}", data)
+        end
+      RUBY
 
+      klass.singleton_class.class_eval <<-RUBY, __FILE__, __LINE__ + 1
+        def digest(data)
+          new.digest(data)
+        end
+        def hexdigest(data)
+          new.hexdigest(data)
+        end
+      RUBY
       const_set(name.tr('-', '_'), klass)
     end
 
diff --git a/test/openssl/test_digest.rb b/test/openssl/test_digest.rb
index 91ed24741..bc1f680df 100644
--- a/test/openssl/test_digest.rb
+++ b/test/openssl/test_digest.rb
@@ -155,6 +155,22 @@ def test_digests
     assert_include digests, "sha256"
     assert_include digests, "sha512"
   end
+
+  if respond_to?(:ractor) && defined?(Ractor.shareable_proc)
+    ractor
+
+    def test_ractor
+      assert_nothing_raised do
+        Ractor.new {
+          [
+            OpenSSL::Digest::SHA256.new(""),
+            OpenSSL::Digest::SHA256.hexdigest(""),
+            OpenSSL::Digest::SHA256.digest(""),
+          ]
+        }.value
+      end
+    end
+  end
 end
 
 end