easy:SetOpt_DoH_SSL_VerifyPeer(verify)
This option is the DoH equivalent of #CURLOPT_SSL_VERIFYPEER and
only affects requests to the DoH server.
When negotiating a TLS or SSL connection, the server sends a certificate
indicating its identity. Curl verifies whether the certificate is authentic,
i.e. that you can trust that the server is who the certificate says it is.
This trust is based on a chain of digital signatures, rooted in certification
authority (CA) certificates you supply. curl uses a default bundle of CA
certificates (the path for that is determined at build time) and you can
specify alternate certificates with the #CURLOPT_CAINFO option
or the #CURLOPT_CAPATH option.
When #CURLOPT_DOH_SSL_VERIFYPEER is enabled, and the verification
fails to prove that the certificate is authentic, the connection fails. When
the option is zero, the peer certificate verification succeeds regardless.
Authenticating the certificate is not enough to be sure about the server. You
typically also want to ensure that the server is the server you mean to be
talking to. Use #CURLOPT_DOH_SSL_VERIFYHOST for that. The check
that the host name in the certificate is valid for the host name you are
connecting to is done independently of the
#CURLOPT_DOH_SSL_VERIFYPEER option.
WARNING: disabling verification of the certificate allows bad guys to man-in-the-middle the communication without you knowing it. Disabling verification makes the communication insecure. Just having encryption on a transfer is not enough as you cannot be sure that you are communicating with the correct end-point.