Add description in X509_STORE manipulation

[openssl.git] / doc / man3 / SSL_CTX_set_psk_client_callback.pod

diff --git a/doc/man3/SSL_CTX_set_psk_client_callback.pod b/doc/man3/SSL_CTX_set_psk_client_callback.pod
index 5350d797ef1f06a14252ddc1bdce8ea6a1675a18..e4b8147e4567a404be09e0177025e111601f270e 100644 (file)
--- a/doc/man3/SSL_CTX_set_psk_client_callback.pod
+++ b/doc/man3/SSL_CTX_set_psk_client_callback.pod
@@ -132,6 +132,14 @@ Note that parameter B<hint> given to the callback may be B<NULL>.
 A connection established via a TLSv1.3 PSK will appear as if session resumption
 has occurred so that L<SSL_session_reused(3)> will return true.
 
+There are no known security issues with sharing the same PSK between TLSv1.2 (or
+below) and TLSv1.3. However the RFC has this note of caution:
+
+"While there is no known way in which the same PSK might produce related output
+in both versions, only limited analysis has been done.  Implementations can
+ensure safety from cross-protocol related output by not reusing PSKs between
+TLS 1.3 and TLS 1.2."
+
 =head1 RETURN VALUES
 
 Return values from the B<SSL_psk_client_cb_func> callback are interpreted as
@@ -158,9 +166,9 @@ were added in OpenSSL 1.1.1.
 
 =head1 COPYRIGHT
 
-Copyright 2006-2017 The OpenSSL Project Authors. All Rights Reserved.
+Copyright 2006-2018 The OpenSSL Project Authors. All Rights Reserved.
 
-Licensed under the OpenSSL license (the "License").  You may not use
+Licensed under the Apache License 2.0 (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
 L<https://www.openssl.org/source/license.html>.