NAME

       SSL_add_expected_rpk, SSL_get_negotiated_client_cert_type, SSL_get_negotiated_server_cert_type,
       SSL_get0_peer_rpk, SSL_SESSION_get0_peer_rpk - raw public key (RFC7250) support

SYNOPSIS

        #include <openssl/ssl.h>

        int SSL_add_expected_rpk(SSL *s, EVP_PKEY *rpk);
        int SSL_get_negotiated_client_cert_type(const SSL *s);
        int SSL_get_negotiated_server_cert_type(const SSL *s);
        EVP_PKEY *SSL_get0_peer_rpk(const SSL *s);
        EVP_PKEY *SSL_SESSION_get0_peer_rpk(const SSL_SESSION *ss);

DESCRIPTION

       SSL_add_expected_rpk() adds a DANE TLSA record matching public key rpk to SSL s's DANE validation policy.

       SSL_get_negotiated_client_cert_type() returns the connection's negotiated client certificate type.

       SSL_get_negotiated_server_cert_type() returns the connection's negotiated server certificate type.

       SSL_get0_peer_rpk() returns the peer's raw public key from SSL s.

       SSL_SESSION_get0_peer_rpk() returns the peer's raw public key from SSL_SESSION ss.

NOTES

       Raw public keys are used in place of certificates when the option is negotiated.  SSL_add_expected_rpk()
       may be called multiple times to configure multiple trusted keys, this makes it possible to allow for key
       rotation, where a peer might be expected to offer an "old" or "new" key and the endpoint must be able to
       accept either one.

       When raw public keys are used, the certificate verify callback is called, and may be used to inspect the
       public key via X509_STORE_CTX_get0_rpk(3).  Raw public keys have no subject, issuer, validity dates nor
       digital signature to verify. They can, however, be matched verbatim or by their digest value, this is
       done by specifying one or more TLSA records, see SSL_CTX_dane_enable(3).

       The raw public key is typically taken from the certificate assigned to the connection (e.g. via
       SSL_use_certificate(3)), but if a certificate is not configured, then the public key will be extracted
       from the assigned private key.

       The SSL_add_expected_rpk() function is a wrapper around SSL_dane_tlsa_add(3).  When DANE is enabled via
       SSL_dane_enable(3), the configured TLSA records will be used to validate the peer's public key or
       certificate.  If DANE is not enabled, then no validation will occur.

RETURN VALUES

       SSL_add_expected_rpk() returns 1 on success and 0 on failure.

       SSL_get0_peer_rpk() and SSL_SESSION_get0_peer_rpk() return the peer's raw public key as an EVP_PKEY or
       NULL when the raw public key is not available.

       SSL_get_negotiated_client_cert_type() and SSL_get_negotiated_server_cert_type() return one of the
       following values:

       TLSEXT_cert_type_x509
       TLSEXT_cert_type_rpk

SEE ALSO

       SSL_CTX_dane_enable(3),     SSL_CTX_set_options(3),     SSL_dane_enable(3),     SSL_get_verify_result(3),
       SSL_set_verify(3), SSL_use_certificate(3), X509_STORE_CTX_get0_rpk(3)

HISTORY

       These functions were added in OpenSSL 3.2.

COPYRIGHT

       Copyright 2023 The OpenSSL Project Authors. All Rights Reserved.

3.4.1                                              2025-04-03                            SSL_GET0_PEER_RPK(3SSL)