diff --git a/test/openssl/test_pkey_rsa.rb b/test/openssl/test_pkey_rsa.rb
new file mode 100644
index 0000000000..36eb2b77eb
--- /dev/null
+++ b/test/openssl/test_pkey_rsa.rb
@@ -0,0 +1,38 @@
+begin
+  require "openssl"
+  require File.join(File.dirname(__FILE__), "utils.rb")
+rescue LoadError
+end
+require 'test/unit'
+
+if defined?(OpenSSL)
+
+class OpenSSL::TestPKeyRSA < Test::Unit::TestCase
+  def test_padding
+    key = OpenSSL::PKey::RSA.new(512, 3)
+
+    # Need right size for raw mode
+    plain0 = "x" * (512/8)
+    cipher = key.private_encrypt(plain0, OpenSSL::PKey::RSA::NO_PADDING)
+    plain1 = key.public_decrypt(cipher, OpenSSL::PKey::RSA::NO_PADDING)
+    assert_equal(plain0, plain1)
+
+    # Need smaller size for pkcs1 mode
+    plain0 = "x" * (512/8 - 11)
+    cipher1 = key.private_encrypt(plain0, OpenSSL::PKey::RSA::PKCS1_PADDING)
+    plain1 = key.public_decrypt(cipher1, OpenSSL::PKey::RSA::PKCS1_PADDING)
+    assert_equal(plain0, plain1)
+
+    cipherdef = key.private_encrypt(plain0) # PKCS1_PADDING is default
+    plain1 = key.public_decrypt(cipherdef)
+    assert_equal(plain0, plain1)
+    assert_equal(cipher1, cipherdef)
+
+    # Failure cases
+    assert_raise(ArgumentError){ key.private_encrypt() }
+    assert_raise(ArgumentError){ key.private_encrypt("hi", 1, nil) }
+    assert_raise(OpenSSL::PKey::RSAError){ key.private_encrypt(plain0, 666) }
+  end
+end
+
+end