1 files changed, 62 insertions, 0 deletions
diff --git a/xmpp-vala/src/module/xep/0384_omemo/omemo_decryptor.vala b/xmpp-vala/src/module/xep/0384_omemo/omemo_decryptor.vala
new file mode 100644
index 00000000..8e3213ae
--- /dev/null
+++ b/xmpp-vala/src/module/xep/0384_omemo/omemo_decryptor.vala
@@ -0,0 +1,62 @@
+using Gee;
+using Xmpp.Xep;
+using Xmpp;
+
+namespace Xmpp.Xep.Omemo {
+
+    public abstract class OmemoDecryptor : XmppStreamModule {
+
+        public static Xmpp.ModuleIdentity<OmemoDecryptor> IDENTITY = new Xmpp.ModuleIdentity<OmemoDecryptor>(NS_URI, "0384_omemo_decryptor");
+
+        public abstract uint32 own_device_id { get; }
+
+        public abstract string decrypt(uint8[] ciphertext, uint8[] key, uint8[] iv) throws GLib.Error;
+
+        public abstract uint8[] decrypt_key(ParsedData data, Jid from_jid) throws GLib.Error;
+
+        public ParsedData? parse_node(StanzaNode encrypted_node) {
+            ParsedData ret = new ParsedData();
+
+            StanzaNode? header_node = encrypted_node.get_subnode("header");
+            if (header_node == null) return null;
+
+            ret.sid = header_node.get_attribute_int("sid", -1);
+            if (ret.sid == -1) return null;
+
+            string? payload_str = encrypted_node.get_deep_string_content("payload");
+            if (payload_str != null) ret.ciphertext = Base64.decode(payload_str);
+
+            string? iv_str = header_node.get_deep_string_content("iv");
+            if (iv_str == null) return null;
+            ret.iv = Base64.decode(iv_str);
+
+            foreach (StanzaNode key_node in header_node.get_subnodes("key")) {
+                debug("Is ours? %d =? %u", key_node.get_attribute_int("rid"), own_device_id);
+                if (key_node.get_attribute_int("rid") == own_device_id) {
+                    string? key_node_content = key_node.get_string_content();
+                    if (key_node_content == null) continue;
+                    uchar[] encrypted_key = Base64.decode(key_node_content);
+                    ret.our_potential_encrypted_keys[new Bytes.take(encrypted_key)] = key_node.get_attribute_bool("prekey");
+                }
+            }
+
+            return ret;
+        }
+
+        public override void attach(XmppStream stream) { }
+        public override void detach(XmppStream stream) { }
+        public override string get_ns() { return NS_URI; }
+        public override string get_id() { return IDENTITY.id; }
+    }
+
+    public class ParsedData {
+        public int sid;
+        public uint8[] ciphertext;
+        public uint8[] iv;
+        public uchar[] encrypted_key;
+        public bool is_prekey;
+
+        public HashMap<Bytes, bool> our_potential_encrypted_keys = new HashMap<Bytes, bool>();
+    }
+}
+