From f1a82fde2a50b242ee73a0b573d633ef3caca343 Mon Sep 17 00:00:00 2001
From: Niels Andriesse <andriesseniels@gmail.com>
Date: Wed, 29 Jan 2020 10:31:43 +1100
Subject: [PATCH] Fix crash

---
 SignalServiceKit/src/Loki/API/LokiSnodeProxy.swift   | 2 +-
 SignalServiceKit/src/Loki/Crypto/DiffieHellman.swift | 1 +
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/SignalServiceKit/src/Loki/API/LokiSnodeProxy.swift b/SignalServiceKit/src/Loki/API/LokiSnodeProxy.swift
index 0298bfde3..84af884ed 100644
--- a/SignalServiceKit/src/Loki/API/LokiSnodeProxy.swift
+++ b/SignalServiceKit/src/Loki/API/LokiSnodeProxy.swift
@@ -79,7 +79,7 @@ internal class LokiSnodeProxy : LokiHTTPClient {
             task.resume()
             return promise
         }.map { rawResponse in
-            guard let data = rawResponse as? Data, let cipherText = Data(base64Encoded: data) else {
+            guard let data = rawResponse as? Data, !data.isEmpty, let cipherText = Data(base64Encoded: data) else {
                 print("[Loki] Received a non-string encoded response.")
                 return rawResponse
             }
diff --git a/SignalServiceKit/src/Loki/Crypto/DiffieHellman.swift b/SignalServiceKit/src/Loki/Crypto/DiffieHellman.swift
index 874a698e3..41198b063 100644
--- a/SignalServiceKit/src/Loki/Crypto/DiffieHellman.swift
+++ b/SignalServiceKit/src/Loki/Crypto/DiffieHellman.swift
@@ -24,6 +24,7 @@ public enum DiffieHellman {
     
     public static func decrypt(_ encryptedData: Data, using symmetricKey: Data) throws -> Data {
         let symmetricKeyBytes = [UInt8](symmetricKey)
+        guard encryptedData.count >= ivLength else { throw "Couldn't decrypt data." }
         let ivBytes = [UInt8](encryptedData[..<ivLength])
         let cipherBytes = [UInt8](encryptedData[ivLength...])
         let blockMode = CBC(iv: ivBytes)