Google has a way to encrypt emails, so that might be a [less secure] way that can work for less technical people, or you could just send them the actual script commands to use for managing an SSH key, and decrypting a file with it, if they're not sure how.
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Google has a way to encrypt emails, so that might be a [less secure] way that can work for less technical people, or you could just send them the actual script commands to use for managing an SSH key, and decrypting a file with it, if they're not sure how.