Fix #158 - unable to share on iOS 18.3.x

Author: alangrainger

manifest.json

@@ -1,7 +1,7 @@
 {
 	"id": "share-note",
 	"name": "Share Note",
-	"version": "1.1.3",
+	"version": "1.2.0",
 	"minAppVersion": "0.15.0",
 	"description": "Instantly share a note, with the full theme and content exactly like you see in Reading View. Data is shared encrypted by default, and only you and the person you send it to have the key.",
 	"author": "Alan Grainger",

package.json

@@ -1,6 +1,6 @@
 {
 	"name": "share-note",
-	"version": "1.1.3",
+	"version": "1.2.0",
 	"description": "Instantly share a note, with the full theme and content exactly like you see in Reading View. Data is shared encrypted by default, and only you and the person you send it to have the key.",
 	"main": "main.js",
 	"scripts": {

src/crypto.ts

@@ -49,7 +49,10 @@ function _getAesGcmKey (secret: ArrayBuffer): Promise<CryptoKey> {
   return window.crypto.subtle.importKey(
     'raw',
     secret,
-    { name: 'AES-GCM', length: 256 },
+    {
+      name: 'AES-GCM',
+      length: 256
+    },
     false,
     ['encrypt', 'decrypt']
   )
@@ -69,7 +72,6 @@ export async function encryptString (plaintext: string, existingKey?: string): P
   } else {
     key = await _generateKey(window.crypto.getRandomValues(new Uint8Array(64)))
   }
-  const iv = new Uint8Array(1)
   const aesKey = await _getAesGcmKey(key)
 
   const ciphertext = []
@@ -79,9 +81,11 @@ export async function encryptString (plaintext: string, existingKey?: string): P
   while (index * chunkSize < length) {
     const plaintextChunk = plaintext.slice(index * chunkSize, (index + 1) * chunkSize)
     const encodedText = new TextEncoder().encode(plaintextChunk)
-    iv[0] = index & 0xFF
     const bufCiphertext: ArrayBuffer = await window.crypto.subtle.encrypt(
-      { name: 'AES-GCM', iv },
+      {
+        name: 'AES-GCM',
+        iv: indexToIv(index)
+      },
       aesKey,
       encodedText
     )
@@ -100,16 +104,17 @@ export async function decryptString (encryptedData: EncryptedString) {
     name: 'AES-GCM',
     length: 256
   }, false, ['decrypt'])
-  const iv = new Uint8Array(1)
 
   const plaintext = []
 
   for (let index = 0; index < encryptedData.ciphertext.length; index++) {
     const ciphertextChunk = encryptedData.ciphertext[index]
-    iv[0] = index & 0xFF
     const ciphertextBuf = base64ToArrayBuffer(ciphertextChunk)
     const plaintextChunk = await window.crypto.subtle
-      .decrypt({ name: 'AES-GCM', iv }, aesKey, ciphertextBuf)
+      .decrypt({
+        name: 'AES-GCM',
+        iv: indexToIv(index)
+      }, aesKey, ciphertextBuf)
     plaintext.push(new TextDecoder().decode(plaintextChunk))
   }
   return plaintext.join('')
@@ -138,3 +143,15 @@ export async function sha1 (data: string | ArrayBuffer) {
 export async function shortHash (text: string) {
   return (await sha256(text)).slice(0, 32)
 }
+
+/**
+ * Take an integer index and return the corresponding IV
+ */
+function indexToIv (int: number) {
+  const iv = new Uint8Array(12)
+  for (let i = 0; i < iv.length; i++) {
+    iv[i] = int % 256
+    int = Math.floor(int / 256)
+  }
+  return iv
+}

versions.json

@@ -22,5 +22,6 @@
 	"1.1.0": "0.15.0",
 	"1.1.1": "0.15.0",
 	"1.1.2": "0.15.0",
-	"1.1.3": "0.15.0"
+	"1.1.3": "0.15.0",
+	"1.2.0": "0.15.0"
 }