From facd74234ebe4fdc92dad1977672a1e88970288c Mon Sep 17 00:00:00 2001
From: Alexandr Savca <alexandr.savca89@gmail.com>
Date: Fri, 20 Dec 2019 14:21:59 +0200
Subject: [PATCH] png.pl: make payload chunk as critical to prevent stripping

---
 png.pl | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/png.pl b/png.pl
index 4f36934..bdbae90 100755
--- a/png.pl
+++ b/png.pl
@@ -129,8 +129,8 @@ sub inject_payload {
     # chunk size
     syswrite $fh, (pack 'I>', length $payload);
 
-    # chunk name: pUnk
-    syswrite $fh, "\x70\x55\x6e\x6b";
+    # chunk name: PUnK (critical)
+    syswrite $fh, "\x50\x55\x6e\x4b";
 
     syswrite $fh, $payload;