calculate pin list checksums in a worker

lib/workers/check-signature.js

@@ -73,17 +73,34 @@ COMMANDS.DETACHED = function (data, cb) {
     cb();
 };
 
+COMMANDS.HASH_CHANNEL_LIST = function (data, cb) {
+    var channels = data.channels;
+    if (!Array.isArray(channels)) { return void cb('INVALID_CHANNEL_LIST'); }
+    var uniques = [];
+
+    channels.forEach(function (a) {
+        if (uniques.indexOf(a) === -1) { uniques.push(a); }
+    });
+    uniques.sort();
+
+    var hash = Nacl.util.encodeBase64(Nacl.hash(Nacl
+        .util.decodeUTF8(JSON.stringify(uniques))));
+
+    cb(void 0, hash);
+};
+
 process.on('message', function (data) {
-    if (!data || !data.key || !data.msg || !data.txid) {
+    if (!data || !data.txid) {
         return void process.send({
             error:'E_INVAL'
         });
     }
 
-    const cb = function (err) {
+    const cb = function (err, value) {
         process.send({
             txid: data.txid,
             error: err,
+            value: value,
         });
     };