The only purpose of the crypto key file is to be used for the password reset procedure. It is sent in your welcome email after the registration. You can also request it in your account:
NOTE: In case you haven't linked the device before the password reset - there is no need to use the keyfile.
In case you have already connected a device to your mSpy account but forgot your password, you need to use the key file that was sent to your email address after the initial setup. If you don't use the key file, you will lose the data that has already been collected from the monitored phone.
Follow the steps below:
1. Go to the email account that you used to purchase mSpy.
2. Enter "Key file" in the search field and find a letter from mSpy.
3. Open the letter and download the attached key file.