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.IX Title "SSL_GET0_PEER_RPK 3ossl"
.TH SSL_GET0_PEER_RPK 3ossl 2026-01-27 3.5.5 OpenSSL
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.nh
.SH 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
.SH SYNOPSIS
.IX Header "SYNOPSIS"
.Vb 1
\& #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);
.Ve
.SH DESCRIPTION
.IX Header "DESCRIPTION"
\&\fBSSL_add_expected_rpk()\fR adds a DANE TLSA record matching public key \fBrpk\fR
to SSL \fBs\fR\*(Aqs DANE validation policy.
.PP
\&\fBSSL_get_negotiated_client_cert_type()\fR returns the connection\*(Aqs negotiated
client certificate type.
.PP
\&\fBSSL_get_negotiated_server_cert_type()\fR returns the connection\*(Aqs negotiated
server certificate type.
.PP
\&\fBSSL_get0_peer_rpk()\fR returns the peer\*(Aqs raw public key from SSL \fBs\fR.
.PP
\&\fBSSL_SESSION_get0_peer_rpk()\fR returns the peer\*(Aqs raw public key from
SSL_SESSION \fBss\fR.
.SH NOTES
.IX Header "NOTES"
Raw public keys are used in place of certificates when the option is
negotiated.
\&\fBSSL_add_expected_rpk()\fR 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.
.PP
When raw public keys are used, the certificate verify callback is called, and
may be used to inspect the public key via \fBX509_STORE_CTX_get0_rpk\fR\|(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 \fBSSL_CTX_dane_enable\fR\|(3).
.PP
The raw public key is typically taken from the certificate assigned to the
connection (e.g. via \fBSSL_use_certificate\fR\|(3)), but if a certificate is not
configured, then the public key will be extracted from the assigned
private key.
.PP
The \fBSSL_add_expected_rpk()\fR function is a wrapper around
\&\fBSSL_dane_tlsa_add\fR\|(3).
When DANE is enabled via \fBSSL_dane_enable\fR\|(3), the configured TLSA records
will be used to validate the peer\*(Aqs public key or certificate.
If DANE is not enabled, then no validation will occur.
.SH "RETURN VALUES"
.IX Header "RETURN VALUES"
\&\fBSSL_add_expected_rpk()\fR returns 1 on success and 0 on failure.
.PP
\&\fBSSL_get0_peer_rpk()\fR and \fBSSL_SESSION_get0_peer_rpk()\fR return the peer\*(Aqs raw
public key as an EVP_PKEY or NULL when the raw public key is not available.
.PP
\&\fBSSL_get_negotiated_client_cert_type()\fR and \fBSSL_get_negotiated_server_cert_type()\fR
return one of the following values:
.IP TLSEXT_cert_type_x509 4
.IX Item "TLSEXT_cert_type_x509"
.PD 0
.IP TLSEXT_cert_type_rpk 4
.IX Item "TLSEXT_cert_type_rpk"
.PD
.SH "SEE ALSO"
.IX Header "SEE ALSO"
\&\fBSSL_CTX_dane_enable\fR\|(3),
\&\fBSSL_CTX_set_options\fR\|(3),
\&\fBSSL_dane_enable\fR\|(3),
\&\fBSSL_get_verify_result\fR\|(3),
\&\fBSSL_set_verify\fR\|(3),
\&\fBSSL_use_certificate\fR\|(3),
\&\fBX509_STORE_CTX_get0_rpk\fR\|(3)
.SH HISTORY
.IX Header "HISTORY"
These functions were added in OpenSSL 3.2.
.SH COPYRIGHT
.IX Header "COPYRIGHT"
Copyright 2023 The OpenSSL Project Authors. All Rights Reserved.
