Check signature for history keeper in a different process

lib/check-signature.js

@@ -0,0 +1,40 @@
+const Nacl = require('tweetnacl/nacl-fast');
+
+// TODO if this process is using too much CPU, we can use "cluster" to add load balancing to this code
+
+process.on('message', function (data) {
+    console.log(+new Date(), "Message received by subprocess");
+    if (!data || !data.key || !data.msg || !data.txid) {
+        process.send({
+            error:'E_INVAL'
+        });
+        return;
+    }
+    const txid = data.txid;
+
+    const signedMsg = Nacl.util.decodeBase64(data.msg);
+    var validateKey;
+    try {
+        validateKey = Nacl.util.decodeBase64(data.key);
+    } catch (e) {
+        process.send({
+            txid: txid,
+            error:'E_BADKEY'
+        });
+        return;
+    }
+    // validate the message
+    const validated = Nacl.sign.open(signedMsg, validateKey);
+    if (!validated) {
+        process.send({
+            txid: txid,
+            error:'FAILED'
+        });
+        return;
+    }
+    console.log(+new Date(), "Verification done in the subprocess");
+    process.send({
+        txid: txid,
+        success: true
+    });
+});