From 3d42c8450fef7767ea9cc05a938523be52ca17be Mon Sep 17 00:00:00 2001
From: AJ ONeal <awesome@coolaj86.com>
Date: Mon, 14 Dec 2015 20:20:29 -0800
Subject: [PATCH] reverse engineering the python client

---
 examples/private-key-json-to-account-id.js | 80 ++++++++++++++++++++++
 1 file changed, 80 insertions(+)
 create mode 100644 examples/private-key-json-to-account-id.js

diff --git a/examples/private-key-json-to-account-id.js b/examples/private-key-json-to-account-id.js
new file mode 100644
index 0000000..3ccd686
--- /dev/null
+++ b/examples/private-key-json-to-account-id.js
@@ -0,0 +1,80 @@
+'use strict';
+
+var fs = require('fs');
+var crypto = require('crypto');
+var ursa = require('ursa');
+
+// Here are all the places you can discover the account id:
+//
+// letsencrypt/account.py
+//
+// /etc/letsencrypt/accounts/{{ server }}/directory/{{ accountId }}/private_key.json
+// /etc/letsencrypt/accounts/acme-v01.api.letsencrypt.org/directory/f4c33502df3789849f617944253b35ae/private_key.json
+//
+// /etc/letsencrypt/renewal/{{ hostname }}.conf
+// /etc/letsencrypt/renewal/example.com.conf
+//
+// Note: each domain has its own private key
+
+function fromPrivateKeyUrsa(priv, cb) {
+  var pub = priv.toPublicPem();
+  var accountId = crypto.createHash('md5').update(pub).digest('hex');
+
+  cb(null, accountId);
+}
+
+function fromAccountPrivateKey(pkj, cb) {
+  Object.keys(pkj).forEach(function (key) {
+    pkj[key] = new Buffer(pkj[key], 'base64');
+  });
+
+  var priv = ursa.createPrivateKeyFromComponents(
+    pkj.n // modulus
+  , pkj.e // exponent
+  , pkj.p
+  , pkj.q
+  , pkj.dp
+  , pkj.dq
+  , pkj.qi
+  , pkj.d
+  );
+
+  fromPrivateKeyUrsa(priv, cb);
+}
+
+function fromAccountPrivateKeyFile(privateKeyPath, cb) {
+  // Read ACME account key
+  fs.readFile(privateKeyPath, 'utf8', function (err, privkeyJson) {
+    var pkj;
+
+    if (err) {
+      cb(err);
+      return;
+    }
+
+    try {
+      pkj = JSON.parse(privkeyJson);
+    } catch(e) {
+      cb(e);
+      return;
+    }
+
+    fromAccountPrivateKey(pkj, cb);
+  });
+}
+
+function bogusAccountId(cb) {
+  var priv = ursa.generatePrivateKey(2048, 65537);
+
+  fromPrivateKeyUrsa(priv, cb);
+}
+
+module.exports.bogusAccountId = bogusAccountId;
+module.exports.fromAccountPrivateKey = fromAccountPrivateKey;
+
+module.exports.bogusAccountId(function (err, id) {
+  console.log('Random Account Id', id);
+});
+module.exports.fromAccountPrivateKey('/etc/letsencrypt/live/example.com/privkey.pem', function (err, id) {
+  console.log(id);
+});