I set up and Encrypted form, No Private key for public encrypted form

I created an encrypted form, received a submission, it is asking for me to upload a private key...I don't know where to find that key. Please help if I need to download one, or help me find and already downloaded file on my computer. 

Thanks 

You should be able to download the Private key when the form encryption is enabled on the form. If you have already downloaded the key (a file with an extension .key), you may be able to find it in your default Downloads folder. If you are not having the key, unfortunately it is not possible to recover the submissions that you have already received. You may disable the Form encryption on the form so that the further received submissions will not be encrypted.

You may turn on the form encryption again so that you can download a new key that works with the new submissions. Please refer to the guide below that can help you with more information on Form encryption.

https://www.jotform.com/help/344-Encrypted-Forms-and-How-to-Use-Them

Hope this information helps! If you have any other questions, please let us know. We will be happy to help.