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23 .TH CURLOPT_PROXY_PINNEDPUBLICKEY 3 "24 Nov 2016" "libcurl 7.52.0" "curl_easy_setopt options"
25 CURLOPT_PROXY_PINNEDPUBLICKEY \- set pinned public key for https proxy
27 #include <curl/curl.h>
29 CURLcode curl_easy_setopt(CURL *handle, CURLOPT_PROXY_PINNEDPUBLICKEY, char *pinnedpubkey);
31 Pass a pointer to a zero terminated string as parameter. The string can be the
32 file name of your pinned public key. The file format expected is "PEM" or "DER".
33 The string can also be any number of base64 encoded sha256 hashes preceded by
34 "sha256//" and separated by ";"
36 When negotiating a TLS or SSL connection, the https proxy sends a certificate
37 indicating its identity. A public key is extracted from this certificate and
38 if it does not exactly match the public key provided to this option, curl will
39 abort the connection before sending or receiving any data.
41 On mismatch, \fICURLE_SSL_PINNEDPUBKEYNOTMATCH\fP is returned.
43 The application does not have to keep the string around after setting this
48 All TLS based protocols: HTTPS, FTPS, IMAPS, POP3S, SMTPS etc.
53 .SH PUBLIC KEY EXTRACTION
54 If you do not have the https proxy server's public key file you can extract it
55 from the https proxy server's certificate.
57 # retrieve the server's certificate if you don't already have it
59 # be sure to examine the certificate to see if it is what you expected
62 # - Use NUL instead of /dev/null.
63 # - OpenSSL may wait for input instead of disconnecting. Hit enter.
64 # - If you don't have sed, then just copy the certificate into a file:
65 # Lines from -----BEGIN CERTIFICATE----- to -----END CERTIFICATE-----.
67 openssl s_client -servername www.example.com -connect www.example.com:443 < /dev/null | sed -n "/-----BEGIN/,/-----END/p" > www.example.com.pem
69 # extract public key in pem format from certificate
70 openssl x509 -in www.example.com.pem -pubkey -noout > www.example.com.pubkey.pem
72 # convert public key from pem to der
73 openssl asn1parse -noout -inform pem -in www.example.com.pubkey.pem -out www.example.com.pubkey.der
75 # sha256 hash and base64 encode der to string for use
76 openssl dgst -sha256 -binary www.example.com.pubkey.der | openssl base64
78 The public key in PEM format contains a header, base64 data and a
81 -----BEGIN PUBLIC KEY-----
83 -----END PUBLIC KEY-----
88 7.52.0: GSKit, GnuTLS, NSS, OpenSSL, PolarSSL, mbedtls, wolfSSL/CyaSSL
92 7.52.0: GnuTLS, NSS, OpenSSL, PolarSSL, mbedtls, wolfSSL/CyaSSL
94 Other SSL backends not supported.
96 Returns CURLE_OK if TLS enabled, CURLE_UNKNOWN_OPTION if not, or
97 CURLE_OUT_OF_MEMORY if there was insufficient heap space.
99 .BR CURLOPT_PROXY_SSL_VERIFYPEER "(3), "
100 .BR CURLOPT_PROXY_SSL_VERIFYHOST "(3), "
101 .BR CURLOPT_PROXY_CAINFO "(3), "
102 .BR CURLOPT_PROXY_CAPATH "(3), "