From dac2e9286cd59f4e81c4791c4ff158ac616eb98c Mon Sep 17 00:00:00 2001
From: C-3PO <c-3po@jedipedia.net>
Date: Thu, 5 Jul 2018 02:55:18 +0200
Subject: [PATCH] =?UTF-8?q?=F0=9F=90=9B=20Update=20decryption=20keys?=
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---
 src/ssn/decryption/decryptChunk.ts | 4 ++--
 src/ssn/streams/decryptStream.ts   | 8 +++++---
 2 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/src/ssn/decryption/decryptChunk.ts b/src/ssn/decryption/decryptChunk.ts
index 7113ad6..5289c53 100644
--- a/src/ssn/decryption/decryptChunk.ts
+++ b/src/ssn/decryption/decryptChunk.ts
@@ -1,6 +1,6 @@
 import updateKeys from './lib/updateKeys';
 
-export default function decryptChunk(encryptedChunk: Buffer, [key0, key1, key2]: [number, number, number]): Buffer {
+export default function decryptChunk(encryptedChunk: Buffer, [key0, key1, key2]: [number, number, number]): {decryptedChunk: Buffer, keys: [number, number, number]} {
   const dv = new DataView(encryptedChunk.buffer);
 
   const decryptedChunk = Buffer.alloc(encryptedChunk.length);
@@ -21,5 +21,5 @@ export default function decryptChunk(encryptedChunk: Buffer, [key0, key1, key2]:
     [key0, key1, key2] = updateKeys([key0, key1, key2], curChar);
   }
 
-  return decryptedChunk;
+  return { decryptedChunk, keys: [key0, key1, key2] };
 }
diff --git a/src/ssn/streams/decryptStream.ts b/src/ssn/streams/decryptStream.ts
index 12cafcb..6f65b69 100644
--- a/src/ssn/streams/decryptStream.ts
+++ b/src/ssn/streams/decryptStream.ts
@@ -1,7 +1,7 @@
 import * as stream from 'stream';
 import decryptChunk from '../decryption/decryptChunk';
 
-export default function decryptStream(inputStream: stream.Readable, decryptionKeys: [number, number, number]): stream.Readable {
+export default function decryptStream(inputStream: stream.Readable, [key0, key1, key2]: [number, number, number]): stream.Readable {
   let skippedRandomHeader = false;
 
   const outStream = new stream.Readable({
@@ -9,7 +9,8 @@ export default function decryptStream(inputStream: stream.Readable, decryptionKe
       //There are 12 random bytes at the beginning, we need to use them to initialize the decryption keys, but we can ignore the decrypted bytes.
       if (!skippedRandomHeader) {
         const encryptedHeader: Buffer = inputStream.read(12);
-        decryptChunk(encryptedHeader, decryptionKeys);
+        const { keys } = decryptChunk(encryptedHeader, [key0, key1, key2]);
+        [key0, key1, key2] = keys;
         skippedRandomHeader = true;
       }
 
@@ -19,7 +20,8 @@ export default function decryptStream(inputStream: stream.Readable, decryptionKe
         //If end has been reached, stop
         this.push(null);
       } else {
-        const decryptedChunk = decryptChunk(encryptedChunk, decryptionKeys);
+        const { decryptedChunk, keys } = decryptChunk(encryptedChunk, [key0, key1, key2]);
+        [key0, key1, key2] = keys;
         this.push(decryptedChunk);
       }
     },