diff --git a/index.js b/index.js
index bdf7734..24c540f 100644
--- a/index.js
+++ b/index.js
@@ -73,7 +73,8 @@ class TuyaLan {
             } catch(ex) {}
 
             //if (!/^[0-9a-f]+$/i.test(device.id)) return this.log.error('%s, id for %s, is not a valid id.', device.id, device.name || 'unnamed device');
-            if (!/^[0-9a-f]+$/i.test(device.key)) return this.log.error('%s, key for %s (%s), is not a valid key.', device.key, device.name || 'unnamed device', device.id);
+            if (!/^[0-9a-f]+$/i.test(device.key)) return this.log.error('%s, key for %s (%s), is not a valid key.', device.key.replace(/.{4}$/, '****'), device.name || 'unnamed device', device.id);
+            if (!{16:1, 24:1, 32: 1}[device.key.length]) return this.log.error('%s, key for %s (%s), doesn\'t have the expected length.', device.key.replace(/.{4}$/, '****'), device.name || 'unnamed device', device.id);
             if (!device.type) return this.log.error('%s (%s) doesn\'t have a type defined.', device.name || 'Unnamed device', device.id);
             if (!CLASS_DEF[device.type.toLowerCase()]) return this.log.error('%s (%s) doesn\'t have a valid type defined.', device.name || 'Unnamed device', device.id);