From c715990992f32119745f2decd0861d4b63efce36 Mon Sep 17 00:00:00 2001
From: snow <kkrautha@andrew.cmu.edu>
Date: Thu, 14 Jan 2016 06:51:16 -0500
Subject: [PATCH] Solved the CryptoStream errors causing the node version
 incompatibilities, now works with up to node 12.5

---
 js/lib/CryptoStream.js | 27 ++++++++++++++++++++++-----
 1 file changed, 22 insertions(+), 5 deletions(-)

diff --git a/js/lib/CryptoStream.js b/js/lib/CryptoStream.js
index 9add37db..9abe1fba 100644
--- a/js/lib/CryptoStream.js
+++ b/js/lib/CryptoStream.js
@@ -69,11 +69,28 @@ CryptoStream.prototype.getCipher = function (callback) {
     cipher.on('readable', function () {
         var chunk = cipher.read();
 
-        if (!ciphertext) {
-            ciphertext = chunk;
-        }
-        else {
-            ciphertext = Buffer.concat([ciphertext, chunk], ciphertext.length + chunk.length);
+        /*
+         The crypto stream error was coming from the additional null packet before the end of the stream
+
+         IE
+            <Buffer a0 4a 2e 8e 2d ce de 12 15 03 7a 42 44 ca 84 88 72 64 77 61 72 65 2f 6f 74 61 5f 63 68 75 6e 6b>
+            <Buffer 5f 73 69 7a 65 ff 35 31 32>
+            null
+            CryptoStream transform error TypeError: Cannot read property 'length' of null
+            Coap Error: Error: Invalid CoAP version. Expected 1, got: 3
+
+        The if statement solves (I believe) all of the node version dependency ussues
+
+        ( Previously required node 10.X, with this tested and working on node 12.5 )
+
+        */
+        if(chunk){
+            if (!ciphertext) {
+                ciphertext = chunk;
+            }
+            else {
+                ciphertext = Buffer.concat([ciphertext, chunk], ciphertext.length + chunk.length);
+            }
         }
     });
     cipher.on('end', function () {