diff --git a/lib/openssl/pkey.rb b/lib/openssl/pkey.rb
index 1aa22bfee..3d1e8885c 100644
--- a/lib/openssl/pkey.rb
+++ b/lib/openssl/pkey.rb
@@ -42,7 +42,7 @@ def public_key
     # The hash has keys 'p', 'q', 'g', 'pub_key', and 'priv_key'.
     def params
       %w{p q g pub_key priv_key}.map { |name|
-        [name, send(name) || 0.to_bn]
+        [name, send(name)]
       }.to_h
     end
 
@@ -174,7 +174,7 @@ def public_key
     # The hash has keys 'p', 'q', 'g', 'pub_key', and 'priv_key'.
     def params
       %w{p q g pub_key priv_key}.map { |name|
-        [name, send(name) || 0.to_bn]
+        [name, send(name)]
       }.to_h
     end
 
@@ -360,7 +360,7 @@ def public_key
     # The hash has keys 'n', 'e', 'd', 'p', 'q', 'dmp1', 'dmq1', and 'iqmp'.
     def params
       %w{n e d p q dmp1 dmq1 iqmp}.map { |name|
-        [name, send(name) || 0.to_bn]
+        [name, send(name)]
       }.to_h
     end
 
diff --git a/test/openssl/test_pkey_dh.rb b/test/openssl/test_pkey_dh.rb
index 88c3d674e..cec1e6301 100644
--- a/test/openssl/test_pkey_dh.rb
+++ b/test/openssl/test_pkey_dh.rb
@@ -138,9 +138,9 @@ def test_params
     assert_not_nil dh.g
     assert_equal dh.g, dh.params["g"]
     assert_nil dh.pub_key
-    assert_equal 0, dh.params["pub_key"]
+    assert_nil dh.params["pub_key"]
     assert_nil dh.priv_key
-    assert_equal 0, dh.params["priv_key"]
+    assert_nil dh.params["priv_key"]
 
     dhkey = OpenSSL::PKey.generate_key(dh)
     assert_equal dh.params["p"], dhkey.params["p"]
diff --git a/test/openssl/test_pkey_dsa.rb b/test/openssl/test_pkey_dsa.rb
index b47a20dfd..c120d74aa 100644
--- a/test/openssl/test_pkey_dsa.rb
+++ b/test/openssl/test_pkey_dsa.rb
@@ -251,7 +251,7 @@ def test_params
     assert_equal key.pub_key, pubkey.pub_key
     assert_equal key.pub_key, pubkey.params["pub_key"]
     assert_nil pubkey.priv_key
-    assert_equal 0, pubkey.params["priv_key"]
+    assert_nil pubkey.params["priv_key"]
   end
 
   def test_dup
diff --git a/test/openssl/test_pkey_rsa.rb b/test/openssl/test_pkey_rsa.rb
index 516d651ae..f47261ccd 100644
--- a/test/openssl/test_pkey_rsa.rb
+++ b/test/openssl/test_pkey_rsa.rb
@@ -535,7 +535,7 @@ def test_params
     pubkey = OpenSSL::PKey.read(key.public_to_der)
     [:d, :p, :q, :dmp1, :dmq1, :iqmp].each do |name|
       assert_nil pubkey.send(name)
-      assert_equal 0, pubkey.params[name.to_s]
+      assert_nil pubkey.params[name.to_s]
     end
   end