diff --git a/phpseclib/Math/BigInteger.php b/phpseclib/Math/BigInteger.php
index 23f8a724..4ac35be1 100644
--- a/phpseclib/Math/BigInteger.php
+++ b/phpseclib/Math/BigInteger.php
@@ -282,7 +282,7 @@ class Math_BigInteger {
             }
         }
 
-        if (function_exists('openssl_public_encrypt') && !defined('MATH_BIGINTEGER_OPENSSL_DISABLE')) {
+        if (function_exists('openssl_public_encrypt') && !defined('MATH_BIGINTEGER_OPENSSL_DISABLE') && !defined('MATH_BIGINTEGER_OPENSSL_ENABLED')) {
             define('MATH_BIGINTEGER_OPENSSL_ENABLED', true);
         }