When you download the app, you have the ability to set a PIN. If you would like to enable/disable your PIN, go to ‘Settings’ in the Whisper app and select the PIN option under "Privacy".
Here you will be prompted to enter your personal PIN number twice to complete the process. If you already have a PIN, it will require that you enter your pin to disable the PIN.
Forgot your PIN and need to reset it? No problem!
Please be sure that you have posted multiple whispers before attempting to reset your PIN. Next, go to ‘Settings’ in the Whisper app, and enter your PIN 3 times. After the third attempt, you will be prompted to reset your PIN.
To make sure that you are the owner of the account, you will have to correctly identify a Whisper post you previously created from a list of whispers. Once identified, you will be prompted to set your new PIN.
Click here for more information on creating a Whisper.