diff --git a/lualib-src/lua-crypt.c b/lualib-src/lua-crypt.c
index 0284c48b..2cb11f40 100644
--- a/lualib-src/lua-crypt.c
+++ b/lualib-src/lua-crypt.c
@@ -338,8 +338,13 @@ static int
 lrandomkey(lua_State *L) {
 	char tmp[8];
 	int i;
+	char x = 0;
 	for (i=0;i<8;i++) {
 		tmp[i] = random() & 0xff;
+		x ^= tmp[i];
+	}
+	if (x==0) {
+		tmp[0] |= 1;	// avoid 0
 	}
 	lua_pushlstring(L, tmp, 8);
 	return 1;
@@ -718,8 +723,13 @@ static int
 ldhsecret(lua_State *L) {
 	uint32_t x[2], y[2];
 	read64(L, x, y);
-	uint64_t r = powmodp((uint64_t)x[0] | (uint64_t)x[1]<<32,
-		(uint64_t)y[0] | (uint64_t)y[1]<<32);
+	uint64_t xx = (uint64_t)x[0] | (uint64_t)x[1]<<32;
+	uint64_t yy = (uint64_t)y[0] | (uint64_t)y[1]<<32;
+	if (xx == 0)
+		xx = 1;
+	if (yy == 0)
+		yy = 1;
+	uint64_t r = powmodp(xx, yy);
 
 	push64(L, r);
 
@@ -739,7 +749,11 @@ ldhexchange(lua_State *L) {
 	xx[0] = x[0] | x[1]<<8 | x[2]<<16 | x[3]<<24;
 	xx[1] = x[4] | x[5]<<8 | x[6]<<16 | x[7]<<24;
 
-	uint64_t r = powmodp(5,	(uint64_t)xx[0] | (uint64_t)xx[1]<<32);
+	uint64_t x64 = (uint64_t)xx[0] | (uint64_t)xx[1]<<32;
+	if (x64 == 0)
+		x64 = 1;
+
+	uint64_t r = powmodp(5,	x64);
 	push64(L, r);
 	return 1;
 }