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SSL_CTX_set_tlsext_use_srtp(3)      OpenSSL     SSL_CTX_set_tlsext_use_srtp(3)



NAME
       SSL_CTX_set_tlsext_use_srtp, SSL_set_tlsext_use_srtp,
       SSL_get_srtp_profiles, SSL_get_selected_srtp_profile - Configure and
       query SRTP support

LIBRARY
       libcrypto, -lcrypto

SYNOPSIS
        #include <openssl/srtp.h>

        int SSL_CTX_set_tlsext_use_srtp(SSL_CTX *ctx, const char *profiles);
        int SSL_set_tlsext_use_srtp(SSL *ssl, const char *profiles);

        STACK_OF(SRTP_PROTECTION_PROFILE) *SSL_get_srtp_profiles(SSL *ssl);
        SRTP_PROTECTION_PROFILE *SSL_get_selected_srtp_profile(SSL *s);

DESCRIPTION
       SRTP is the Secure Real-Time Transport Protocol. OpenSSL implements
       support for the "use_srtp" DTLS extension defined in RFC5764. This
       provides a mechanism for establishing SRTP keying material, algorithms
       and parameters using DTLS. This capability may be used as part of an
       implementation that conforms to RFC5763. OpenSSL does not implement
       SRTP itself or RFC5763. Note that OpenSSL does not support the use of
       SRTP Master Key Identifiers (MKIs). Also note that this extension is
       only supported in DTLS. Any SRTP configuration will be ignored if a TLS
       connection is attempted.

       An OpenSSL client wishing to send the "use_srtp" extension should call
       SSL_CTX_set_tlsext_use_srtp() to set its use for all SSL objects
       subsequently created from an SSL_CTX. Alternatively a client may call
       SSL_set_tlsext_use_srtp() to set its use for an individual SSL object.
       The profiles parameters should point to a NUL-terminated, colon
       delimited list of SRTP protection profile names.

       The currently supported protection profile names are:

       SRTP_AES128_CM_SHA1_80
           This corresponds to SRTP_AES128_CM_HMAC_SHA1_80 defined in RFC5764.

       SRTP_AES128_CM_SHA1_32
           This corresponds to SRTP_AES128_CM_HMAC_SHA1_32 defined in RFC5764.

       SRTP_AEAD_AES_128_GCM
           This corresponds to the profile of the same name defined in
           RFC7714.

       SRTP_AEAD_AES_256_GCM
           This corresponds to the profile of the same name defined in
           RFC7714.

       Supplying an unrecognised protection profile name will result in an
       error.

       An OpenSSL server wishing to support the "use_srtp" extension should
       also call SSL_CTX_set_tlsext_use_srtp() or SSL_set_tlsext_use_srtp() to
       indicate the protection profiles that it is willing to negotiate.

       The currently configured list of protection profiles for either a
       client or a server can be obtained by calling SSL_get_srtp_profiles().
       This returns a stack of SRTP_PROTECTION_PROFILE objects. The memory
       pointed to in the return value of this function should not be freed by
       the caller.

       After a handshake has been completed the negotiated SRTP protection
       profile (if any) can be obtained (on the client or the server) by
       calling SSL_get_selected_srtp_profile(). This function will return NULL
       if no SRTP protection profile was negotiated. The memory returned from
       this function should not be freed by the caller.

       If an SRTP protection profile has been successfully negotiated then the
       SRTP keying material (on both the client and server) should be obtained
       via a call to SSL_export_keying_material(3). This call should provide a
       label value of "EXTRACTOR-dtls_srtp" and a NULL context value
       (use_context is 0). The total length of keying material obtained should
       be equal to two times the sum of the master key length and the salt
       length as defined for the protection profile in use. This provides the
       client write master key, the server write master key, the client write
       master salt and the server write master salt in that order.

RETURN VALUES
       SSL_CTX_set_tlsext_use_srtp() and SSL_set_tlsext_use_srtp() return 0 on
       success or 1 on error.

       SSL_get_srtp_profiles() returns a stack of SRTP_PROTECTION_PROFILE
       objects on success or NULL on error or if no protection profiles have
       been configured.

       SSL_get_selected_srtp_profile() returns a pointer to an
       SRTP_PROTECTION_PROFILE object if one has been negotiated or NULL
       otherwise.

SEE ALSO
       SSL_export_keying_material(3)

COPYRIGHT
       Copyright 2017-2018 The OpenSSL Project Authors. All Rights Reserved.

       Licensed under the OpenSSL license (the "License").  You may not use
       this file except in compliance with the License.  You can obtain a copy
       in the file LICENSE in the source distribution or at
       <https://www.openssl.org/source/license.html>.



1.1.1                             2018-09-17    SSL_CTX_set_tlsext_use_srtp(3)