diff --git a/src/main/java/org/jruby/ext/openssl/ASN1.java b/src/main/java/org/jruby/ext/openssl/ASN1.java
index fbe08bb9..5ce07456 100644
--- a/src/main/java/org/jruby/ext/openssl/ASN1.java
+++ b/src/main/java/org/jruby/ext/openssl/ASN1.java
@@ -1390,20 +1390,26 @@ final ASN1TaggedObject toASN1TaggedObject(final ThreadContext context) {
                 if ( arr.size() > 1 ) {
                     ASN1EncodableVector vec = new ASN1EncodableVector();
                     for ( final IRubyObject obj : arr.toJavaArray() ) {
-                        ASN1Encodable data = ((ASN1Data) obj).toASN1(context);
+                        ASN1Encodable data = ((ASN1OctetString) obj).toASN1(context);
                         if ( data == null ) break; vec.add( data );
                     }
                     return new DERTaggedObject(isExplicitTagging(), tag, new DERSequence(vec));
                 }
                 else if ( arr.size() == 1 ) {
-                    ASN1Encodable data = ((ASN1Data) arr.entry(0)).toASN1(context);
+                    ASN1Encodable data = ((ASN1OctetString) arr.entry(0)).toASN1(context);
                     return new DERTaggedObject(isExplicitTagging(), tag, data);
                 }
                 else {
                     throw new IllegalStateException("empty array detected");
                 }
+            } else if (val instanceof RubyString || val instanceof java.lang.String) {
+                return new DERTaggedObject(isExplicitTagging(), tag, ((ASN1OctetString) val).toASN1(context));
+            } else if (val instanceof ASN1OctetString) {
+                return new DERTaggedObject(isExplicitTagging(), tag, val.toASN1(context));
+            } else {
+                throw runtime.newTypeError("no implicit conversion of " + val.getMetaClass().getName() + " into String");
             }
-            return new DERTaggedObject(isExplicitTagging(), tag, ((ASN1Data) val).toASN1(context));
+
         }
 
         @JRubyMethod
diff --git a/src/test/ruby/test_asn1.rb b/src/test/ruby/test_asn1.rb
index 95f55137..cb697c08 100644
--- a/src/test/ruby/test_asn1.rb
+++ b/src/test/ruby/test_asn1.rb
@@ -21,6 +21,16 @@ def test_encode_integer
     assert_equal i, OpenSSL::ASN1.decode(ai.to_der).value
   end
 
+  def test_encode_asn1_data
+    ai = OpenSSL::ASN1::ASN1Data.new(i = "bla", 0, :APPLICATION)
+    assert_equal i, OpenSSL::ASN1.decode(ai.to_der).value
+
+    ai = OpenSSL::ASN1::ASN1Data.new(i = ["bla"], 0, :APPLICATION)
+    assert_equal i, OpenSSL::ASN1.decode(ai.to_der).value
+
+    assert_raise(TypeError) { OpenSSL::ASN1::ASN1Data.new(1).to_der }
+  end
+
   def test_encode_nil
     #Primitives raise TypeError, Constructives NoMethodError