The closest you can get is to verify the hostname and certificate by using the ssl_opts option. Once you have saved the file to disk, there is no way to assure its integrity.

You could sign the file from your program, maybe using gpg, while writing it, but nothing prevents somebody with access to the machine/account to sign other files as well.

In reply to Re: Extract digital signature from HTTPS response by Corion
in thread Extract digital signature from HTTPS response by stringZ

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