Send OMEMO-encrypted messages and files using 12 byte IV

2 files changed, 6 insertions, 10 deletions

diff --git a/plugins/omemo/src/file_transfer/file_decryptor.vala b/plugins/omemo/src/file_transfer/file_decryptor.vala
index 7aec41d5..fedb9397 100644
--- a/plugins/omemo/src/file_transfer/file_decryptor.vala
+++ b/plugins/omemo/src/file_transfer/file_decryptor.vala
@@ -52,14 +52,8 @@ public class OmemoFileDecryptor : FileDecryptor, Object {
             MatchInfo match_info;
             this.url_regex.match(omemo_http_receive_data.original_url, 0, out match_info);
             uint8[] iv_and_key = hex_to_bin(match_info.fetch(2).up());
-            uint8[] iv, key;
-            if (iv_and_key.length == 44) {
-                iv = iv_and_key[0:12];
-                key = iv_and_key[12:44];
-            } else {
-                iv = iv_and_key[0:16];
-                key = iv_and_key[16:48];
-            }
+            uint8[] iv = iv_and_key[0:iv_and_key.length-16];
+            uint8[] key = iv_and_key[iv_and_key.length-16:iv_and_key.length];
 
             file_transfer.encryption = Encryption.OMEMO;
             debug("Decrypting file %s from %s", file_transfer.file_name, file_transfer.server_file_name);
diff --git a/plugins/omemo/src/file_transfer/file_encryptor.vala b/plugins/omemo/src/file_transfer/file_encryptor.vala
index 31c3ad6c..7e79abdc 100644
--- a/plugins/omemo/src/file_transfer/file_encryptor.vala
+++ b/plugins/omemo/src/file_transfer/file_encryptor.vala
@@ -20,13 +20,15 @@ public class OmemoFileEncryptor : Dino.FileEncryptor, Object {
     }
 
     public FileMeta encrypt_file(Conversation conversation, FileTransfer file_transfer) throws FileSendError {
+        const uint KEY_SIZE = 32;
+        const uint IV_SIZE = 12;
         var omemo_http_file_meta = new OmemoHttpFileMeta();
 
         try {
             //Create a key and use it to encrypt the file
-            uint8[] iv = new uint8[16];
+            uint8[] iv = new uint8[IV_SIZE];
             Plugin.get_context().randomize(iv);
-            uint8[] key = new uint8[32];
+            uint8[] key = new uint8[KEY_SIZE];
             Plugin.get_context().randomize(key);
 
             SymmetricCipher cipher = new SymmetricCipher("AES-GCM");