From 9994dffed2a4d7e3bc293c67b277fafe37290d56 Mon Sep 17 00:00:00 2001
From: C-3PO <c-3po@jedipedia.net>
Date: Thu, 5 Jul 2018 18:22:20 +0200
Subject: [PATCH] =?UTF-8?q?=F0=9F=90=9B=20Fix=20decrypt=20chunk?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 src/ssn/decryption/decryptChunk.ts | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/src/ssn/decryption/decryptChunk.ts b/src/ssn/decryption/decryptChunk.ts
index 3370756..f98ceee 100644
--- a/src/ssn/decryption/decryptChunk.ts
+++ b/src/ssn/decryption/decryptChunk.ts
@@ -19,11 +19,12 @@ import updateKeys from './lib/updateKeys';
   return { decryptedChunk, keys: [key0, key1, key2] };
 }*/
 
-export default function getDecryptor([key0, key1, key2]: [number, number, number]) {
+export default function getDecryptor(decryptionKeys: [number, number, number]) {
+  let [key0, key1, key2] = decryptionKeys;
   let position = 0;
 
   return (encryptedChunk: Buffer) => {
-    const decryptedChunk = Buffer.alloc(encryptedChunk.length);
+    const decryptedChunk = Buffer.alloc(encryptedChunk.length - Math.max(12 - position, 0));
 
     for (let i = 0; i < encryptedChunk.length; i += 1) {
       //read byte
@@ -34,6 +35,9 @@ export default function getDecryptor([key0, key1, key2]: [number, number, number
       const decryptedByte = (keyPart * (keyPart ^ 1)) >>> 8;
       curChar ^= decryptedByte & 0xFF;
 
+      //update keys
+      [key0, key1, key2] = updateKeys([key0, key1, key2], curChar);
+
       //write byte
       if (position + i < 12) {
         //do nothing
@@ -42,9 +46,6 @@ export default function getDecryptor([key0, key1, key2]: [number, number, number
       } else {
         decryptedChunk.writeUInt8(curChar, i);
       }
-
-      //update keys
-      [key0, key1, key2] = updateKeys([key0, key1, key2], curChar);
     }
 
     position += encryptedChunk.length;