diff --git a/configure.ac b/configure.ac
index 92a3605544cd236893f957fe88be7f4a52257224..1e88477328121bad3d3c6497172f84cc57a36f8b 100644
--- a/configure.ac
+++ b/configure.ac
@@ -236,7 +236,7 @@ fi
 # Checks for libraries
 if test "x$enable_public_key" = "xyes" ; then
   if test "x$enable_mini_gmp" = "xno" ; then
-    AC_CHECK_LIB(gmp, __gmpz_mpz_powm,,
+    AC_CHECK_LIB(gmp, __gmpz_powm_sec,,
         [AC_MSG_WARN(
     [GNU MP not found, or too old. GMP-5.0 or later is needed, see http://gmplib.org/.
     Support for public key algorithms will be unavailable.])]