master-server/deps/curl/docs/cmdline-opts/proxy-pinnedpubkey.md

c	SPDX-License-Identifier	Long	Arg	Help	Protocols	Category	Added	Multi	See-also	Example
Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.	curl	proxy-pinnedpubkey	<hashes>	FILE/HASHES public key to verify proxy with	TLS	proxy tls	7.59.0	single	pinnedpubkey proxy	--proxy-pinnedpubkey keyfile $URL --proxy-pinnedpubkey 'sha256//ce118b51897f4452dc' $URL

--proxy-pinnedpubkey

Use the specified public key file (or hashes) to verify the proxy. This can be a path to a file which contains a single public key in PEM or DER format, or any number of base64 encoded sha256 hashes preceded by 'sha256//' and separated by ';'.

When negotiating a TLS or SSL connection, the server sends a certificate indicating its identity. A public key is extracted from this certificate and if it does not exactly match the public key provided to this option, curl aborts the connection before sending or receiving any data.