diff --git a/asc2qr.sh b/asc2qr.sh
index a10e3ef..7bba162 100755
--- a/asc2qr.sh
+++ b/asc2qr.sh
@@ -40,8 +40,8 @@ if [ $# -ne 1 ]; then
 fi
 
 asc_key=${1}
-if [ ! -f ${asc_key} ]; then
-	echo "key file not found: ${asc_key}"
+if [ ! -f "${asc_key}" ]; then
+	echo "key file not found: '${asc_key}'"
 	exit 1
 fi
 
diff --git a/qr2asc.sh b/qr2asc.sh
index 43f27ff..9aadda8 100755
--- a/qr2asc.sh
+++ b/qr2asc.sh
@@ -37,13 +37,13 @@ fi
 chunks=()
 index=1
 for img in "$@"; do
-	if [ ! -f ${img} ]; then
-		echo "image file not found: ${img}"
+	if [ ! -f "${img}" ]; then
+		echo "image file not found: '${img}'"
 		exit 1
 	fi
 	asc_key="${tmp_file}.${index}"
 	echo "decoding ${img}"
-    chunk=$( zbarimg --raw --set disable --set qrcode.enable ${img} 2>/dev/null )
+    chunk=$( zbarimg --raw --set disable --set qrcode.enable "${img}" 2>/dev/null )
 	if [ $? -ne 0 ]; then
 		echo "failed to decode QR image"
 		exit 2