diff --git a/ChangeLog b/ChangeLog
index 4896600020..5fc77c368a 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Sat Apr 16 03:59:42 2005  GOTOU Yuuzou  <gotoyuzo@notwork.org>
+
+	* ext/openssl/extconf.rb: check for OPENSSL_cleanse.
+
+	* ext/openssl/openssl_missing.h: ditto.
+
 Thu Apr 14 19:18:30 2005  Minero Aoki  <aamine@loveruby.net>
 
 	* lib/fileutils.rb (remove_file): ignore exceptions caused by
diff --git a/ext/openssl/extconf.rb b/ext/openssl/extconf.rb
index 4517ec82fb..2ced7f62ce 100644
--- a/ext/openssl/extconf.rb
+++ b/ext/openssl/extconf.rb
@@ -89,6 +89,7 @@ have_func("X509_CRL_set_version")
 have_func("X509_CRL_sort")
 have_func("X509_STORE_get_ex_data")
 have_func("X509_STORE_set_ex_data")
+have_func("OPENSSL_cleanse")
 if try_compile("#define FOO(a, ...) foo(a, ##__VA_ARGS__)\n int x(){FOO(1);FOO(1,2);FOO(1,2,3);}\n")
   $defs.push("-DHAVE_VA_ARGS_MACRO")
 end
diff --git a/ext/openssl/openssl_missing.h b/ext/openssl/openssl_missing.h
index 2a082f3fe0..e8c75ca42c 100644
--- a/ext/openssl/openssl_missing.h
+++ b/ext/openssl/openssl_missing.h
@@ -103,6 +103,10 @@ int EVP_CIPHER_CTX_copy(EVP_CIPHER_CTX *out, EVP_CIPHER_CTX *in);
 #  define PKCS7_type_is_encrypted(a) (OBJ_obj2nid((a)->type) == NID_pkcs7_encrypted)
 #endif
 
+#if !defined(HAVE_OPENSSL_CLEANSE)
+#define OPENSSL_cleanse(p, l) memset(p, 0, l)
+#endif
+
 void *X509_STORE_get_ex_data(X509_STORE *str, int idx);
 int X509_STORE_set_ex_data(X509_STORE *str, int idx, void *data);
 int X509_CRL_set_version(X509_CRL *x, long version);