diff --git a/crypto/bn/exponentiation.c b/crypto/bn/exponentiation.c
index f7100ac..b168347 100644
--- a/crypto/bn/exponentiation.c
+++ b/crypto/bn/exponentiation.c
@@ -209,6 +209,7 @@
   BN_init(&recp->N);
   BN_init(&recp->Nr);
   recp->num_bits = 0;
+  recp->shift = 0;
   recp->flags = 0;
 }