chore(crypto): add doc for the generateIv function

Author: timoa

src/lib/crypto.js

@@ -1,11 +1,15 @@
 const crypto = require('crypto');
 
+const algorithm = 'AES-256-GCM';
+
+/**
+ * Generate an Initialization Vector
+ * @returns {Buffer}
+ */
 function generateIv() {
   return crypto.randomBytes(32);
 }
 
-const algorithm = 'AES-256-GCM';
-
 /**
  * Encrypt a secret
  * @param {String} data           Data to encrypt