diff --git a/bignum.h b/bignum.h
index 64ed2787f14e22ac06fc5b9e3982f2ca45cb5fa5..0d305342407d9092e2f32fa9be4c976eeea22fe7 100644
--- a/bignum.h
+++ b/bignum.h
@@ -54,7 +54,7 @@
 # define mpz_import mpz_import
 # define mpz_export mpz_export
 /* Side-channel silent powm not available in mini-gmp. */
-# define mpz_powm_sec mpz_pwm
+# define mpz_powm_sec mpz_powm
 #else
 # include <gmp.h>
 #endif