1SSL_export_keying_material(3)       OpenSSL      SSL_export_keying_material(3)
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NAME

6       SSL_export_keying_material - obtain keying material for application use
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SYNOPSIS

9        #include <openssl/ssl.h>
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11        int SSL_export_keying_material(SSL *s, unsigned char *out, size_t olen,
12                                       const char *label, size_t llen,
13                                       const unsigned char *context,
14                                       size_t contextlen, int use_context);
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DESCRIPTION

17       During the creation of a TLS or DTLS connection shared keying material
18       is established between the two endpoints. The function
19       SSL_export_keying_material() enables an application to use some of this
20       keying material for its own purposes in accordance with RFC5705.
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22       An application may need to securely establish the context within which
23       this keying material will be used. For example this may include
24       identifiers for the application session, application algorithms or
25       parameters, or the lifetime of the context. The context value is left
26       to the application but must be the same on both sides of the
27       communication.
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29       For a given SSL connection s, olen bytes of data will be written to
30       out. The application specific context should be supplied in the
31       location pointed to by context and should be contextlen bytes long.
32       Provision of a context is optional. If the context should be omitted
33       entirely then use_context should be set to 0. Otherwise it should be
34       any other value. If use_context is 0 then the values of context and
35       contextlen are ignored.  Note that a zero length context is treated
36       differently to no context at all, and will result in different keying
37       material being returned.
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39       An application specific label should be provided in the location
40       pointed to by label and should be llen bytes long. Typically this will
41       be a value from the IANA Exporter Label Registry
42       (<https://www.iana.org/assignments/tls-parameters/tls-parameters.xhtml#exporter-labels>).
43       Alternatively labels beginning with "EXPERIMENTAL" are permitted by the
44       standard to be used without registration.
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46       Note that this function is only defined for TLSv1.0 and above, and
47       DTLSv1.0 and above. Attempting to use it in SSLv3 will result in an
48       error.
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RETURN VALUES

51       SSL_export_keying_material() returns 0 or -1 on failure or 1 on
52       success.
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55       Copyright 2017 The OpenSSL Project Authors. All Rights Reserved.
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57       Licensed under the OpenSSL license (the "License").  You may not use
58       this file except in compliance with the License.  You can obtain a copy
59       in the file LICENSE in the source distribution or at
60       <https://www.openssl.org/source/license.html>.
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641.0.2o                            2020-08-01     SSL_export_keying_material(3)
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