Android permissions are one of the most important aspects of the operating system. They are there to protect your privacy and security.
The three types of permissions are normal, dangerous, and signature. Normal permissions are required to use various applications on the phone. Dangerous permissions allow for more sensitive actions that may compromise your privacy or security. Signature permissions are used by apps that come from sources other than Google Play Store or Android Market.
Normal Permissions: The normal type of permission is required by any app that wants to access certain features on your device such as reading contact data, receiving text messages, or accessing the camera. These permissions can be denied by you at any time if you feel uncomfortable with them being granted automatically while installing an app.