READ_CONTACTS:
Calls and SMS Blocker, needs to read contacts and show them in a list so that you can choose to add numbers to blacklist or whitelist.
READ_CALL_LOG:
Calls and SMS Blocker, needs to read call logs and show them in a list so that you can choose to add numbers to blacklist or whitelist.
READ_SMS:
Calls and SMS Blocker, needs to read sms received and show them in a list so that you can choose to add numbers to blacklist or whitelist.
READ_PHONE_STATE:
Calls and SMS Blocker, needs to read phone state to block incoming call in blacklist.
SEND_SMS AND RECEIVE_SMS:
Calls and SMS Blocker, needs to allow send and receive sms, if you block messages on android 4.4 or higher, to manage your messages.