diff --git a/src/main/java/org/jruby/ext/openssl/ASN1.java b/src/main/java/org/jruby/ext/openssl/ASN1.java
index a4c52f47..c939e948 100644
--- a/src/main/java/org/jruby/ext/openssl/ASN1.java
+++ b/src/main/java/org/jruby/ext/openssl/ASN1.java
@@ -1931,19 +1931,17 @@ private byte[] setToDER(final ThreadContext context) throws IOException {
         private ASN1EncodableVector toASN1EncodableVector(final ThreadContext context) {
             final ASN1EncodableVector vec = new ASN1EncodableVector();
             final IRubyObject value = value(context);
-            if ( value instanceof RubyArray ) {
-                final RubyArray val = (RubyArray) value;
-                for ( int i = 0; i < val.size(); i++ ) {
-                    if ( addEntry(context, vec, val.entry(i)) ) break;
+            final RubyArray val;
+            if (value instanceof RubyArray ) {
+                val = (RubyArray) value;
+            } else {
+                if (!value.respondsTo("to_a")) {
+                    throw context.runtime.newTypeError("can't convert " + value.getMetaClass().getName() + " into Array");
                 }
+                val = (RubyArray) value.callMethod(context, "to_a");
             }
-            else {
-                final int size = RubyInteger.num2int(value.callMethod(context, "size"));
-                for ( int i = 0; i < size; i++ ) {
-                    final RubyInteger idx = context.runtime.newFixnum(i);
-                    IRubyObject entry = value.callMethod(context, "[]", idx);
-                    if ( addEntry(context, vec, entry) ) break;
-                }
+            for ( int i = 0; i < val.size(); i++ ) {
+                if ( addEntry(context, vec, val.entry(i)) ) break;
             }
             return vec;
         }
diff --git a/src/test/ruby/test_asn1.rb b/src/test/ruby/test_asn1.rb
index 9b9b0ca0..f82595fe 100644
--- a/src/test/ruby/test_asn1.rb
+++ b/src/test/ruby/test_asn1.rb
@@ -26,11 +26,6 @@ def test_encode_nil
 
     assert_raise(TypeError) { OpenSSL::ASN1::Integer.new(nil).to_der }
     assert_raise(TypeError) { OpenSSL::ASN1::Boolean.new(nil).to_der }
-
-    # NOTE: MRI does not raise
-    assert_raise(NoMethodError) { OpenSSL::ASN1::Set.new(nil).to_der }
-    # NOTE: MRI does not raise
-    assert_raise(NoMethodError) { OpenSSL::ASN1::Sequence.new(nil).to_der }
   end
 
   def test_instantiate
@@ -167,6 +162,14 @@ def test_constructive_nesting
     assert_equal expected, name.to_der
   end
 
+  def test_sequence_convert_to_array
+    data_sequence = ::OpenSSL::ASN1::Sequence([::OpenSSL::ASN1::Integer(0)])
+    asn1 = ::OpenSSL::ASN1::Sequence(data_sequence)
+    assert_equal "0\x03\x02\x01\x00" , asn1.to_der
+
+    assert_raise(TypeError) { ::OpenSSL::ASN1::Sequence(::OpenSSL::ASN1::Integer(0)).to_der }
+  end
+
   def test_raw_constructive
     eoc = OpenSSL::ASN1::EndOfContent.new
     #puts "eoc: #{eoc.inspect}"