From c00ac1ff51c795d4d93c32e0a913e2cebf917d0c Mon Sep 17 00:00:00 2001
From: Biswakalyan Bhuyan <biswa@surgot.in>
Date: Thu, 25 Jul 2024 12:09:28 +0530
Subject: added backend and login portal

---
 backend/node_modules/cookie-signature/index.js | 51 ++++++++++++++++++++++++++
 1 file changed, 51 insertions(+)
 create mode 100644 backend/node_modules/cookie-signature/index.js

(limited to 'backend/node_modules/cookie-signature/index.js')

diff --git a/backend/node_modules/cookie-signature/index.js b/backend/node_modules/cookie-signature/index.js
new file mode 100644
index 0000000..b8c9463
--- /dev/null
+++ b/backend/node_modules/cookie-signature/index.js
@@ -0,0 +1,51 @@
+/**
+ * Module dependencies.
+ */
+
+var crypto = require('crypto');
+
+/**
+ * Sign the given `val` with `secret`.
+ *
+ * @param {String} val
+ * @param {String} secret
+ * @return {String}
+ * @api private
+ */
+
+exports.sign = function(val, secret){
+  if ('string' != typeof val) throw new TypeError("Cookie value must be provided as a string.");
+  if ('string' != typeof secret) throw new TypeError("Secret string must be provided.");
+  return val + '.' + crypto
+    .createHmac('sha256', secret)
+    .update(val)
+    .digest('base64')
+    .replace(/\=+$/, '');
+};
+
+/**
+ * Unsign and decode the given `val` with `secret`,
+ * returning `false` if the signature is invalid.
+ *
+ * @param {String} val
+ * @param {String} secret
+ * @return {String|Boolean}
+ * @api private
+ */
+
+exports.unsign = function(val, secret){
+  if ('string' != typeof val) throw new TypeError("Signed cookie string must be provided.");
+  if ('string' != typeof secret) throw new TypeError("Secret string must be provided.");
+  var str = val.slice(0, val.lastIndexOf('.'))
+    , mac = exports.sign(str, secret);
+  
+  return sha1(mac) == sha1(val) ? str : false;
+};
+
+/**
+ * Private
+ */
+
+function sha1(str){
+  return crypto.createHash('sha1').update(str).digest('hex');
+}
-- 
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