diff --git a/sshrsa.c b/sshrsa.c
index 4ec95f23..25f9cf7e 100644
--- a/sshrsa.c
+++ b/sshrsa.c
@@ -264,6 +264,7 @@ static Bignum rsa_privkey_op(Bignum input, struct RSAKey *key)
 	    bitsleft--;
 	    bignum_set_bit(random, bits, v);
 	}
+        bn_restore_invariant(random);
 
 	/*
 	 * Now check that this number is strictly greater than