diff --git a/src/core/ddsi/CMakeLists.txt b/src/core/ddsi/CMakeLists.txt
index e0aaaa8..75c2342 100644
--- a/src/core/ddsi/CMakeLists.txt
+++ b/src/core/ddsi/CMakeLists.txt
@@ -20,6 +20,7 @@ PREPEND(srcs_ddsi "${CMAKE_CURRENT_LIST_DIR}/src"
     ddsi_mcgroup.c
     ddsi_security_omg.c
     ddsi_portmapping.c
+    ddsi_handshake.c
     ddsi_serdata.c
     ddsi_serdata_default.c
     ddsi_sertopic.c
@@ -77,6 +78,7 @@ PREPEND(hdrs_private_ddsi "${CMAKE_CURRENT_LIST_DIR}/include/dds/ddsi"
     ddsi_plist_generic.h
     ddsi_security_omg.h
     ddsi_portmapping.h
+    ddsi_handshake.h    
     ddsi_serdata.h
     ddsi_sertopic.h
     ddsi_serdata_default.h
diff --git a/src/core/ddsi/include/dds/ddsi/ddsi_entity_index.h b/src/core/ddsi/include/dds/ddsi/ddsi_entity_index.h
index 78a353e..1566feb 100644
--- a/src/core/ddsi/include/dds/ddsi/ddsi_entity_index.h
+++ b/src/core/ddsi/include/dds/ddsi/ddsi_entity_index.h
@@ -112,6 +112,7 @@ struct entidx_enum_proxy_reader { struct entidx_enum st; };
 
 void entidx_enum_init (struct entidx_enum *st, const struct entity_index *ei, enum entity_kind kind) ddsrt_nonnull_all;
 void entidx_enum_init_topic (struct entidx_enum *st, const struct entity_index *gh, enum entity_kind kind, const char *topic, struct match_entities_range_key *max) ddsrt_nonnull_all;
+void entidx_enum_init_topic_w_prefix (struct entidx_enum *st, const struct entity_index *ei, enum entity_kind kind, const char *topic, const ddsi_guid_prefix_t *prefix, struct match_entities_range_key *max) ddsrt_nonnull_all;
 void *entidx_enum_next_max (struct entidx_enum *st, const struct match_entities_range_key *max) ddsrt_nonnull_all;
 void *entidx_enum_next (struct entidx_enum *st) ddsrt_nonnull_all;
 void entidx_enum_fini (struct entidx_enum *st) ddsrt_nonnull_all;
diff --git a/src/core/ddsi/include/dds/ddsi/ddsi_handshake.h b/src/core/ddsi/include/dds/ddsi/ddsi_handshake.h
new file mode 100644
index 0000000..1aef76d
--- /dev/null
+++ b/src/core/ddsi/include/dds/ddsi/ddsi_handshake.h
@@ -0,0 +1,197 @@
+/*
+ * Copyright(c) 2006 to 2018 ADLINK Technology Limited and others
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v. 2.0 which is available at
+ * http://www.eclipse.org/legal/epl-2.0, or the Eclipse Distribution License
+ * v. 1.0 which is available at
+ * http://www.eclipse.org/org/documents/edl-v10.php.
+ *
+ * SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause
+ */
+#ifndef DDSI_HANDSHAKE_H
+#define DDSI_HANDSHAKE_H
+
+#include "q_unused.h"
+#include "q_entity.h"
+#include "ddsi_security_msg.h"
+
+#if defined (__cplusplus)
+extern "C" {
+#endif
+
+struct participant;
+struct proxy_participant;
+struct ddsi_handshake;
+struct dssi_hsadmin;
+
+enum ddsi_handshake_state {
+    STATE_HANDSHAKE_IN_PROGRESS,
+    STATE_HANDSHAKE_TIMED_OUT,
+    STATE_HANDSHAKE_FAILED,
+    STATE_HANDSHAKE_PROCESSED,
+    STATE_HANDSHAKE_SEND_TOKENS,
+    STATE_HANDSHAKE_OK
+};
+
+/* The handshake will not use the related handshake object after this callback
+ * was executed. This means that it can be deleted in this callback. */
+typedef void (*ddsi_handshake_end_cb_t)(
+    struct q_globals const * const gv,
+    struct ddsi_handshake *handshake,
+    const ddsi_guid_t *lpguid, /* Local participant */
+    const ddsi_guid_t *ppguid, /* Proxy participant */
+    enum ddsi_handshake_state result);
+
+#ifdef DDSI_INCLUDE_SECURITY
+
+#include "dds/ddsi/ddsi_security_msg.h"
+
+/**
+ * @brief Release the handshake.
+ *
+ * This function will decrement the refcount associated with the handshake
+ * and delete the handshake when the refcount becomes 0.
+ *
+ * @param[in] handshake    The handshake.
+ */
+void ddsi_handshake_release(struct ddsi_handshake *handshake);
+
+/**
+ * @brief Handle an authentication handshake message received from the remote participant.
+ *
+ * During the authentication phase handshake messages are being exchanged between the local and
+ * the remote participant. THis function will handle a handshake message received from a remote
+ * participant.
+ *
+ * @param[in] handshake  The handshake.
+ * @param[in] pp         The local participant.
+ * @param[in] proxypp    The remote participant.
+ * @param[in] msg        The handshake message received.
+ */
+void ddsi_handshake_handle_message(struct ddsi_handshake *handshake, const struct participant *pp, const struct proxy_participant *proxypp, const struct nn_participant_generic_message *msg);
+
+/**
+ * @brief Notify the handshake that crypto tokens have been received.
+ *
+ * The handshake could be finished at one end while the other side has not yet processed the
+ * final handshake messages. The arrival of crypto tokens signals that the other side has also finished
+ * processing the handshake. This function is used to signal the handshake that crypto tokens have been
+ * received.
+ *
+ * @param[in] handshake     The handshake.
+ */
+void ddsi_handshake_crypto_tokens_received(struct ddsi_handshake *handshake);
+
+/**
+ * @brief Get the shared secret handle.
+ *
+ * During the handshake a shared secret is established which is used to encrypt
+ * and decrypt the crypto token exchange messages. This function will return a
+ * handle to the shared secret which will be passed to the crypto plugin to
+ * determine the session keys used for the echange of the the crypto tokens.
+ *
+ * @param[in] handshake  The handshake.
+ *
+ * @returns handle to the shared sercet.
+ */
+int64_t ddsi_handshake_get_shared_secret(const struct ddsi_handshake *handshake);
+
+/**
+ * @brief Get the handshake handle
+ *
+ * This function returns the handshake handle that was returned by the authentication plugin
+ * when starting the handshake.
+ *
+ * @param[in]  handshake  The handshake.
+ *
+ * @returns The handshake handle.
+ */
+int64_t ddsi_handshake_get_handle(const struct ddsi_handshake *handshake);
+
+/**
+ * @brief Create and start the handshake for the participants
+ *
+ * This function will create a handshake for the specified local
+ * and remote participants when it does not yet exists. It will start the
+ * handshake procedure by calling the corresponding functions of the authentication plugin.
+ * The callback function is called by the handshake when to report events,
+ * for example to indicate that the handshake has finished or has failed.
+ *
+ * @param[in] pp         The local participant.
+ * @param[in] proxypp    The remote participant.
+ * @param[in] callback   The callback function.
+ *
+ */
+void ddsi_handshake_register(const struct participant *pp, const struct proxy_participant *proxypp, ddsi_handshake_end_cb_t callback);
+
+/**
+ * @brief Remove the handshake associated with the specified participants.
+ *
+ * This function will remove the handshake from the handshake administation and release
+ * the handshake. When the handshake argument is not specified the handshake is searched
+ * in the handshake administation.
+ *
+ * @param[in] pp         The local participant.
+ * @param[in] proxypp    The remote participant.
+ * @param[in] handshake  The handshake.
+ *
+ */
+void ddsi_handshake_remove(const struct participant *pp, const struct proxy_participant *proxypp, struct ddsi_handshake *handshake);
+
+/**
+ * @brief Searches for the handshake associated with the specified participants
+ *
+ * This function will search through the handshake administration to find the handshake
+ * corresponding the to specified local and remote participant.
+ *
+ * @param[in] pp         The local participant.
+ * @param[in] proxypp    The remote participant.
+ *
+ * @returns The handshake
+ */
+struct ddsi_handshake * ddsi_handshake_find(const struct participant *pp, const struct proxy_participant *proxypp);
+
+#else /* DDSI_INCLUDE_SECURITY */
+
+#include "dds/ddsi/q_unused.h"
+
+
+inline void ddsi_handshake_release(UNUSED_ARG(struct ddsi_handshake *handshake))
+{
+}
+
+inline void ddsi_handshake_crypto_tokens_received(UNUSED_ARG(struct ddsi_handshake *handshake))
+{
+}
+
+inline int64_t ddsi_handshake_get_shared_secret(UNUSED_ARG(const struct ddsi_handshake *handshake))
+{
+  return 0;
+}
+
+inline int64_t ddsi_handshake_get_handle(UNUSED_ARG(const struct ddsi_handshake *handshake))
+{
+  return 0;
+}
+
+inline void ddsi_handshake_register(UNUSED_ARG(const struct participant *pp), UNUSED_ARG(const struct proxy_participant *proxypp), UNUSED_ARG(ddsi_handshake_end_cb_t callback))
+{
+}
+
+inline void ddsi_handshake_remove(UNUSED_ARG(const struct participant *pp), UNUSED_ARG(const struct proxy_participant *proxypp), UNUSED_ARG(struct ddsi_handshake *handshake))
+{
+}
+
+inline struct ddsi_handshake * ddsi_handshake_find(UNUSED_ARG(const struct participant *pp), UNUSED_ARG(const struct proxy_participant *proxypp))
+{
+  return NULL;
+}
+
+#endif /* DDSI_INCLUDE_SECURITY */
+
+#if defined (__cplusplus)
+}
+#endif
+
+#endif /* DDSI_HANDSHAKE_H */
diff --git a/src/core/ddsi/include/dds/ddsi/ddsi_security_msg.h b/src/core/ddsi/include/dds/ddsi/ddsi_security_msg.h
index 2db227c..e8ced85 100644
--- a/src/core/ddsi/include/dds/ddsi/ddsi_security_msg.h
+++ b/src/core/ddsi/include/dds/ddsi/ddsi_security_msg.h
@@ -12,6 +12,8 @@
 #ifndef DDSI_SECURITY_MSG_H
 #define DDSI_SECURITY_MSG_H
 
+#ifdef DDSI_INCLUDE_SECURITY
+
 #include "dds/ddsi/q_plist.h"
 #include "dds/ddsi/ddsi_guid.h"
 #include "dds/ddsrt/retcode.h"
@@ -108,4 +110,6 @@ volatile_secure_data_filter(
 }
 #endif
 
+#endif
+
 #endif /* DDSI_SECURITY_MSG_H */
diff --git a/src/core/ddsi/include/dds/ddsi/ddsi_security_omg.h b/src/core/ddsi/include/dds/ddsi/ddsi_security_omg.h
index 316954d..7ad3425 100644
--- a/src/core/ddsi/include/dds/ddsi/ddsi_security_omg.h
+++ b/src/core/ddsi/include/dds/ddsi/ddsi_security_omg.h
@@ -57,6 +57,17 @@ bool q_omg_security_enabled(void);
  */
 bool q_omg_participant_is_secure(const struct participant *pp);
 
+/**
+ * @brief Check if security is enabled for the proxy participant.
+ *
+ * @param[in] proxypp  Proxy participant to check if it is secure.
+ *
+ * @returns bool
+ * @retval true   Proxy participant is secure
+ * @retval false  Proxy participant is not secure
+ */
+bool q_omg_proxy_participant_is_secure(const struct proxy_participant *proxypp);
+
 /**
  * @brief Get the security handle of the given local participant.
  *
@@ -490,6 +501,195 @@ secure_conn_write(
     nn_msg_sec_info_t *sec_info,
     ddsi_tran_write_fn_t conn_write_cb);
 
+/**
+ * @brief Check if the participant and the proxy participant
+ *        have compatible security info settings.
+ *
+ * Associated with a secure participant is the ParticipantSecurityInfo parameter.
+ * This parameter contains the setting of the security attributes and the associated
+ * plugin security attributes of the secure participant.
+ * This function will check if the received ParticipantSecurityInfo parameter is
+ * compatible with the local ParticipantSecurityInfo parameter.
+ *
+ * @param[in] pp      The participant.
+ * @param[in] proxypp The proxy participant.
+ *
+ * @returns bool
+ * @retval true   The participant and the proxy participant have compatible
+ *                security info settings.
+ * @retval false  Otherwise.
+ */
+bool q_omg_is_similar_participant_security_info(struct participant *pp, struct proxy_participant *proxypp);
+
+/**
+ * @brief Check if the participant allows communication with unauthenticated
+ *        participants
+ *
+ * @param[in] pp  The participant.
+ *
+ * @returns bool
+ * @retval true   The participant allows unauthenticated communication
+ * @retval false  Otherwise.
+ */
+bool q_omg_participant_allow_unauthenticated(struct participant *pp);
+
+/**
+ * @brief Register participant with security plugin and check if the
+ *        participant is allowed by security.
+ *
+ * This function will register the participant with the authentication
+ * plugin which will check if the provided security QoS parameters are
+ * correct, e.g. is the provided certificate valid, etc.
+ * When that is successful it is checked with access control if the
+ * participant has the correct permissions and is allowed to be created.
+ *
+ * @param[in] pp        The participant.
+ * @param[in] domain_id The domain id.
+ *
+ * @returns bool
+ * @retval true   The security check on the participant succeeded.
+ * @retval false  The security check on the participant failed.
+ */
+bool q_omg_security_check_create_participant(struct participant *pp, uint32_t domain_id);
+
+/**
+ * @brief Initialize the proxy participant security attributes
+ *
+ * @param[in] proxypp  The proxy participant.
+ *
+ */
+void q_omg_security_init_remote_participant(struct proxy_participant *proxypp);
+
+/**
+ * @brief Check the if the proxy participant is allowed by checking the security permissions.
+ *
+ * The access control plugin is ask to verify if the proxy participant is allowed to
+ * communicate with the local participant. When the proxy participant is allowed the
+ * function will return a valid permission handle which is provided by the access control plugin.
+ *
+ * @param[in] domain_id The domain id
+ * @param[in] pp        The participant
+ * @param[in] proxypp   The proxy participant
+ *
+ * @returns permission handle
+ * @retval !0    The proxy participant is allowed
+ * @retval 0     The proxy participant is not allowed.
+ */
+int64_t q_omg_security_check_remote_participant_permissions(uint32_t domain_id, struct participant *pp, struct proxy_participant *proxypp);
+
+/**
+ * @brief Registers the matched proxy participant with the crypto plugin
+ *
+ * When the proxy participant is authenticated and allowed by access control then the match between the local and
+ * the remote participant must be registered with the cypto factory provided by the crypto plugin. The
+ * shared secret handle obtained from the authentication phase and the permission handle returned when validating
+ * the proxy participant with access control plugin have to be provided.
+ *
+ *
+ * @param[in] pp                 The participant.
+ * @param[in] proxypp            The proxy participant.
+ * @param[in] shared_secret      The shared_secret handle.
+ * @param[in] proxy_permissions  The permission handle associated with the proxy participant.
+ */
+void q_omg_security_register_remote_participant(struct participant *pp, struct proxy_participant *proxypp, int64_t shared_secret, int64_t proxy_permissions);
+
+/**
+ * @brief Removes a registered proxy participant from administation of the authentication,
+ *        access control and crypto plugins.
+ *
+ * @param[in] proxypp            The proxy participant.
+ */
+void q_omg_security_deregister_remote_participant(struct proxy_participant *proxypp);
+
+/**
+ * @brief Generate and send the crypto tokens needed for encoding RTPS messages.
+ *
+ * When the security settings indicate that RTPS message encoding or signing is
+ * configured for the participant then this function will ask the cypto echange for
+ * the corresponding cypto tokens and send these to the proxy participant.
+ *
+ * @param[in] pp                 The participant.
+ * @param[in] proxypp            The proxy participant.
+ */
+void q_omg_security_participant_send_tokens(struct participant *pp, struct proxy_participant *proxypp);
+
+/**
+ * @brief Check if the remote writer is allowed to communicate with endpoints of the
+ *        local participant.
+ *
+ * This function will check with the access control plugin if the remote writer
+ * is allowed to communicate with this participant.
+ *
+ * @param[in] pwr       The remote writer.
+ * @param[in] domain_id The domain id.
+ * @param[in] pp        The local participant.
+ *
+ * @returns bool
+ * @retval true   The remote writer is allowed to communicate.
+ * @retval false  Otherwise.
+ */
+bool q_omg_security_check_remote_writer_permissions(const struct proxy_writer *pwr, uint32_t domain_id, struct participant *pp);
+
+/**
+ * @brief Check if the remote reader is allowed to communicate with endpoints of the
+ *        local participant.
+ *
+ * This function will check with the access control plugin if the remote reader
+ * is allowed to communicate with this participant.
+ *
+ * @param[in] prd       The remote reader.
+ * @param[in] domain_id The domain id.
+ * @param[in] pp        The local participant.
+ *
+ * @returns bool
+ * @retval true   The remote reader is allowed to communicate.
+ * @retval false  Otherwise.
+ */
+bool q_omg_security_check_remote_reader_permissions(const struct proxy_reader *prd, uint32_t domain_id, struct participant *pp);
+
+/**
+ * @brief Check it the remote writer is allowed to communicate with the local reader.
+ *
+ * When a remote writer is allowed by access control it has to be checked if the remote
+ * writer is allowed to communicate with a particular local reader. This function will
+ * check if the provided security end-point attributes are compatible, When the security
+ * attributes are compatible then the function will register the reader and remote writer
+ * match with the crypto factory and will also ask the crypto exchange to generate the
+ * crypto tokens associate with the local reader which will be sent to the remote entity.
+ * Note that the reader crypto tokens are used to encrypt the reader specific submessages
+ * when submessage encoding or signing is configured.
+ *
+ * @param[in] rd   The local reader.
+ * @param[in] pwr  The remote writer.
+ *
+ * @returns bool
+ * @retval true   The local reader and remote writer are allowed to communicate.
+ * @retval false  Otherwise.
+ */
+bool q_omg_security_match_remote_writer_enabled(struct reader *rd, struct proxy_writer *pwr);
+
+/**
+ * @brief Check it the local writer is allowed to communicate with the remote reader.
+ *
+ * When a remote reader is allowed by access control it has to be checked if the local
+ * writer is allowed to communicate with a particular local writer. This function will
+ * check if the provided security end-point attributes are compatible, When the security
+ * attributes are compatible then the function will register the writer and remote reader
+ * match with the crypto factory and will also ask the crypto exchange to generate the
+ * crypto tokens associate with the local writer which will be sent to the remote entity.
+ * Note that the writer crypto tokens are used to encrypt the writer specific submessages
+ * when submessage encoding or signing is configured and also the crypto tokens used
+ * for encoding the payload of data or datafrag messages.
+ *
+ * @param[in] wr   The local writer.
+ * @param[in] prd  The remote reader.
+ *
+ * @returns bool
+ * @retval true   The local writer and remote reader are allowed to communicate.
+ * @retval false  Otherwise.
+ */
+bool q_omg_security_match_remote_reader_enabled(struct writer *wr, struct proxy_reader *prd);
+
 #else /* DDSI_INCLUDE_SECURITY */
 
 #include "dds/ddsi/q_unused.h"
@@ -507,6 +707,13 @@ q_omg_participant_is_secure(
   return false;
 }
 
+inline bool
+q_omg_proxy_participant_is_secure(
+  UNUSED_ARG(const struct proxy_participant *proxypp))
+{
+  return false;
+}
+
 inline unsigned
 determine_subscription_writer(
   UNUSED_ARG(const struct reader *rd))
@@ -530,6 +737,65 @@ is_proxy_participant_deletion_allowed(
   return true;
 }
 
+inline bool q_omg_is_similar_participant_security_info(UNUSED_ARG(struct participant *pp), UNUSED_ARG(struct proxy_participant *proxypp))
+{
+  return true;
+}
+
+inline bool q_omg_participant_allow_unauthenticated(UNUSED_ARG(struct participant *pp))
+{
+  return true;
+}
+
+inline bool
+q_omg_security_check_create_participant(UNUSED_ARG(struct participant *pp), UNUSED_ARG(uint32_t domain_id))
+{
+  return true;
+}
+
+inline void q_omg_security_init_remote_participant(UNUSED_ARG(struct proxy_participant *proxypp))
+{
+}
+
+inline int64_t q_omg_security_check_remote_participant_permissions(UNUSED_ARG(uint32_t domain_id), UNUSED_ARG(struct participant *pp), UNUSED_ARG(struct proxy_participant *proxypp))
+{
+  return 0LL;
+}
+
+inline void q_omg_security_register_remote_participant(UNUSED_ARG(struct participant *pp), UNUSED_ARG(struct proxy_participant *proxypp), UNUSED_ARG(int64_t shared_secret), UNUSED_ARG(int64_t proxy_permissions))
+{
+}
+
+inline void q_omg_security_deregister_remote_participant(UNUSED_ARG(struct proxy_participant *proxypp))
+{
+}
+
+inline void q_omg_security_participant_send_tokens(UNUSED_ARG(struct participant *pp), UNUSED_ARG(struct proxy_participant *proxypp))
+{
+}
+
+inline bool q_omg_security_match_remote_writer_enabled(UNUSED_ARG(struct reader *rd), UNUSED_ARG(struct proxy_writer *pwr))
+{
+  return true;
+}
+
+inline bool q_omg_security_match_remote_reader_enabled(UNUSED_ARG(struct writer *wr), UNUSED_ARG(struct proxy_reader *prd))
+{
+  return true;
+}
+
+inline bool
+q_omg_security_check_remote_writer_permissions(UNUSED_ARG(const struct proxy_writer *pwr), UNUSED_ARG(uint32_t domain_id), UNUSED_ARG(struct participant *pp))
+{
+  return true;
+}
+
+inline bool
+q_omg_security_check_remote_reader_permissions(UNUSED_ARG(const struct proxy_reader *prd), UNUSED_ARG(uint32_t domain_id), UNUSED_ARG(struct participant *pp))
+{
+  return true;
+}
+
 inline void
 set_proxy_participant_security_info(
   UNUSED_ARG(struct proxy_participant *prd),
@@ -551,7 +817,6 @@ set_proxy_writer_security_info(
 {
 }
 
-
 inline bool
 decode_Data(
   UNUSED_ARG(const struct q_globals *gv),
diff --git a/src/core/ddsi/include/dds/ddsi/q_entity.h b/src/core/ddsi/include/dds/ddsi/q_entity.h
index 66c6ca1..2e3eba4 100644
--- a/src/core/ddsi/include/dds/ddsi/q_entity.h
+++ b/src/core/ddsi/include/dds/ddsi/q_entity.h
@@ -20,11 +20,13 @@
 #include "dds/ddsi/q_rtps.h"
 #include "dds/ddsi/q_plist.h"
 #include "dds/ddsi/q_protocol.h"
+#include "dds/ddsi/q_plist.h"
 #include "dds/ddsi/q_lat_estim.h"
 #include "dds/ddsi/q_hbcontrol.h"
 #include "dds/ddsi/q_feature_check.h"
 #include "dds/ddsi/q_inverse_uint32_set.h"
 #include "dds/ddsi/ddsi_serdata_default.h"
+#include "dds/ddsi/ddsi_handshake.h"
 
 #include "dds/ddsi/ddsi_tran.h"
 
@@ -214,6 +216,11 @@ struct participant
   int32_t builtin_refc; /* number of built-in endpoints in this participant [refc_lock] */
   int builtins_deleted; /* whether deletion of built-in endpoints has been initiated [refc_lock] */
   ddsrt_fibheap_t ldur_auto_wr; /* Heap that contains lease duration for writers with automatic liveliness in this participant */
+#ifdef DDSI_INCLUDE_SECURITY
+  int64_t local_identity_handle;   /* OMG DDS Security related member */
+  int64_t permissions_handle; /* OMG DDS Security related member */
+  struct participant_sec_attributes *sec_attr;
+#endif
 };
 
 struct endpoint_common {
@@ -356,7 +363,9 @@ struct proxy_participant
   unsigned proxypp_have_cm: 1;
   unsigned owns_lease: 1;
 #ifdef DDSI_INCLUDE_SECURITY
+  int64_t remote_identity_handle;   /* OMG DDS Security related member */
   nn_security_info_t security_info;
+  struct proxy_participant_sec_attributes *sec_attr;
 #endif
 };
 
@@ -712,6 +721,10 @@ void rebuild_or_clear_writer_addrsets(struct q_globals *gv, int rebuild);
 
 void local_reader_ary_setfastpath_ok (struct local_reader_ary *x, bool fastpath_ok);
 
+void connect_writer_with_proxy_reader_secure(struct writer *wr, struct proxy_reader *prd, nn_mtime_t tnow);
+void connect_reader_with_proxy_writer_secure(struct reader *rd, struct proxy_writer *pwr, nn_mtime_t tnow);
+
+
 struct ddsi_writer_info;
 DDS_EXPORT void ddsi_make_writer_info(struct ddsi_writer_info *wrinfo, const struct entity_common *e, const struct dds_qos *xqos, uint32_t statusinfo);
 
diff --git a/src/core/ddsi/src/ddsi_entity_index.c b/src/core/ddsi/src/ddsi_entity_index.c
index c7b09b9..b22488b 100644
--- a/src/core/ddsi/src/ddsi_entity_index.c
+++ b/src/core/ddsi/src/ddsi_entity_index.c
@@ -439,6 +439,18 @@ void entidx_enum_init_topic (struct entidx_enum *st, const struct entity_index *
     st->cur = NULL;
 }
 
+void entidx_enum_init_topic_w_prefix (struct entidx_enum *st, const struct entity_index *ei, enum entity_kind kind, const char *topic, const ddsi_guid_prefix_t *prefix, struct match_entities_range_key *max)
+{
+  assert (kind == EK_READER || kind == EK_WRITER || kind == EK_PROXY_READER || kind == EK_PROXY_WRITER);
+  struct match_entities_range_key min;
+  match_endpoint_range (kind, topic, &min, max);
+  min.entity.e.guid.prefix = *prefix;
+  max->entity.e.guid.prefix = *prefix;
+  entidx_enum_init_minmax_int (st, ei, &min);
+  if (st->cur && all_entities_compare (st->cur, &max->entity) > 0)
+    st->cur = NULL;
+}
+
 void entidx_enum_init (struct entidx_enum *st, const struct entity_index *ei, enum entity_kind kind)
 {
   struct match_entities_range_key min;
diff --git a/src/core/ddsi/src/ddsi_handshake.c b/src/core/ddsi/src/ddsi_handshake.c
new file mode 100644
index 0000000..13d8390
--- /dev/null
+++ b/src/core/ddsi/src/ddsi_handshake.c
@@ -0,0 +1,109 @@
+/*
+ * Copyright(c) 2006 to 2018 ADLINK Technology Limited and others
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v. 2.0 which is available at
+ * http://www.eclipse.org/legal/epl-2.0, or the Eclipse Distribution License
+ * v. 1.0 which is available at
+ * http://www.eclipse.org/org/documents/edl-v10.php.
+ *
+ * SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause
+ */
+
+#include "dds/ddsi/ddsi_handshake.h"
+
+#ifdef DDSI_INCLUDE_SECURITY
+
+#include "dds/security/dds_security_api.h"
+#include "dds/ddsrt/hopscotch.h"
+
+struct ddsi_handshake
+{
+  enum ddsi_handshake_state state;
+
+  ddsi_guid_t local_pguid;  /* the guid of the local participant */
+  ddsi_guid_t remote_pguid; /* the guid of the remote participant */
+  ddsi_handshake_end_cb_t end_cb;
+  struct q_globals *gv;
+  ddsrt_mutex_t lock;
+  ddsrt_cond_t cv;
+
+  ddsrt_atomic_uint32_t refc;
+
+  DDS_Security_IdentityHandle local_identity_handle;
+  DDS_Security_IdentityHandle remote_identity_handle;
+  DDS_Security_HandshakeHandle handshake_handle;
+
+  DDS_Security_HandshakeMessageToken handshake_message_in_token;
+  nn_message_identity_t handshake_message_in_id;
+  DDS_Security_HandshakeMessageToken *handshake_message_out;
+  DDS_Security_AuthRequestMessageToken local_auth_request_token;
+  DDS_Security_AuthRequestMessageToken *remote_auth_request_token;
+  DDS_Security_OctetSeq pdata;
+  DDS_Security_SharedSecretHandle shared_secret;
+  int handled_handshake_message;
+};
+
+
+void ddsi_handshake_handle_message(struct ddsi_handshake *handshake, const struct participant *pp, const struct proxy_participant *proxypp, const struct nn_participant_generic_message *msg)
+{
+  DDSRT_UNUSED_ARG(handshake);
+  DDSRT_UNUSED_ARG(pp);
+  DDSRT_UNUSED_ARG(proxypp);
+  DDSRT_UNUSED_ARG(msg);
+}
+
+void ddsi_handshake_crypto_tokens_received(struct ddsi_handshake *handshake)
+{
+  DDSRT_UNUSED_ARG(handshake);
+}
+
+int64_t ddsi_handshake_get_shared_secret(const struct ddsi_handshake *handshake)
+{
+  DDSRT_UNUSED_ARG(handshake);
+
+  return 0;
+}
+
+int64_t ddsi_handshake_get_handle(const struct ddsi_handshake *handshake)
+{
+  DDSRT_UNUSED_ARG(handshake);
+
+  return 0;
+}
+
+void ddsi_handshake_register(const struct participant *pp, const struct proxy_participant *proxypp, ddsi_handshake_end_cb_t callback)
+{
+  DDSRT_UNUSED_ARG(pp);
+  DDSRT_UNUSED_ARG(proxypp);
+  DDSRT_UNUSED_ARG(callback);
+}
+
+void ddsi_handshake_remove(const struct participant *pp, const struct proxy_participant *proxypp, struct ddsi_handshake *handshake)
+{
+  DDSRT_UNUSED_ARG(pp);
+  DDSRT_UNUSED_ARG(proxypp);
+  DDSRT_UNUSED_ARG(handshake);
+}
+
+struct ddsi_handshake * ddsi_handshake_find(const struct participant *pp, const struct proxy_participant *proxypp)
+{
+  DDSRT_UNUSED_ARG(pp);
+  DDSRT_UNUSED_ARG(proxypp);
+
+  return NULL;
+}
+
+
+#else
+
+extern inline void ddsi_handshake_release(UNUSED_ARG(struct ddsi_handshake *handshake));
+extern inline void ddsi_handshake_crypto_tokens_received(UNUSED_ARG(struct ddsi_handshake *handshake));
+extern inline int64_t ddsi_handshake_get_shared_secret(UNUSED_ARG(const struct ddsi_handshake *handshake));
+extern inline int64_t ddsi_handshake_get_handle(UNUSED_ARG(const struct ddsi_handshake *handshake));
+extern inline void ddsi_handshake_register(UNUSED_ARG(const struct participant *pp), UNUSED_ARG(const struct proxy_participant *proxypp), UNUSED_ARG(ddsi_handshake_end_cb_t callback));
+extern inline void ddsi_handshake_remove(UNUSED_ARG(const struct participant *pp), UNUSED_ARG(const struct proxy_participant *proxypp), UNUSED_ARG(struct ddsi_handshake *handshake));
+extern inline struct ddsi_handshake * ddsi_handshake_find(UNUSED_ARG(const struct participant *pp), UNUSED_ARG(const struct proxy_participant *proxypp));
+
+
+#endif /* DDSI_INCLUDE_DDS_SECURITY */
diff --git a/src/core/ddsi/src/ddsi_security_omg.c b/src/core/ddsi/src/ddsi_security_omg.c
index 32f3b11..10fca50 100644
--- a/src/core/ddsi/src/ddsi_security_omg.c
+++ b/src/core/ddsi/src/ddsi_security_omg.c
@@ -92,6 +92,15 @@ q_omg_participant_is_secure(
   return false;
 }
 
+bool
+q_omg_proxy_participant_is_secure(
+    const struct proxy_participant *proxypp)
+{
+  /* TODO: Register remote participant */
+  DDSRT_UNUSED_ARG(proxypp);
+  return false;
+}
+
 static bool
 q_omg_writer_is_discovery_protected(
   const struct writer *wr)
@@ -147,6 +156,12 @@ q_omg_get_reader_security_info(
   return false;
 }
 
+void
+q_omg_security_init_remote_participant(struct proxy_participant *proxypp)
+{
+  DDSRT_UNUSED_ARG(proxypp);
+}
+
 static bool
 q_omg_proxyparticipant_is_authenticated(
   const struct proxy_participant *proxy_pp)
@@ -174,6 +189,14 @@ q_omg_security_get_remote_participant_handle(
   return 0;
 }
 
+bool
+q_omg_participant_allow_unauthenticated(struct participant *pp)
+{
+  DDSRT_UNUSED_ARG(pp);
+
+  return true;
+}
+
 unsigned
 determine_subscription_writer(
   const struct reader *rd)
@@ -196,6 +219,21 @@ determine_publication_writer(
   return NN_ENTITYID_SEDP_BUILTIN_PUBLICATIONS_WRITER;
 }
 
+void
+q_omg_security_register_remote_participant(struct participant *pp, struct proxy_participant *proxypp, int64_t shared_secret, int64_t proxy_permissions)
+{
+  DDSRT_UNUSED_ARG(pp);
+  DDSRT_UNUSED_ARG(proxypp);
+  DDSRT_UNUSED_ARG(shared_secret);
+  DDSRT_UNUSED_ARG(proxy_permissions);
+}
+
+void
+q_omg_security_deregister_remote_participant(struct proxy_participant *proxypp)
+{
+  DDSRT_UNUSED_ARG(proxypp);
+}
+
 bool
 is_proxy_participant_deletion_allowed(
   struct q_globals * const gv,
@@ -225,6 +263,93 @@ is_proxy_participant_deletion_allowed(
   return (!q_omg_proxyparticipant_is_authenticated(proxypp));
 }
 
+/* ask to access control security plugin for the remote participant permissions */
+int64_t
+q_omg_security_check_remote_participant_permissions(uint32_t domain_id, struct participant *pp, struct proxy_participant *proxypp)
+{
+  DDSRT_UNUSED_ARG(domain_id);
+  DDSRT_UNUSED_ARG(pp);
+  DDSRT_UNUSED_ARG(proxypp);
+
+  return 0;
+}
+
+bool
+q_omg_is_similar_participant_security_info(struct participant *pp, struct proxy_participant *proxypp)
+{
+  DDSRT_UNUSED_ARG(pp);
+  DDSRT_UNUSED_ARG(proxypp);
+
+  return true;
+}
+
+bool
+q_omg_security_check_create_participant(struct participant *pp, uint32_t domain_id)
+{
+  DDSRT_UNUSED_ARG(pp);
+  DDSRT_UNUSED_ARG(domain_id);
+  return true;
+}
+
+void
+q_omg_security_participant_send_tokens(struct participant *pp, struct proxy_participant *proxypp)
+{
+  DDSRT_UNUSED_ARG(pp);
+  DDSRT_UNUSED_ARG(proxypp);
+}
+
+bool
+q_omg_security_match_remote_writer_enabled(struct reader *rd, struct proxy_writer *pwr)
+{
+  DDSRT_UNUSED_ARG(rd);
+  DDSRT_UNUSED_ARG(pwr);
+
+  assert(rd);
+  assert(pwr);
+
+  return true;
+}
+
+bool
+q_omg_security_match_remote_reader_enabled(struct writer *wr, struct proxy_reader *prd)
+{
+  DDSRT_UNUSED_ARG(wr);
+  DDSRT_UNUSED_ARG(prd);
+
+  assert(wr);
+  assert(prd);
+
+  return true;
+}
+
+bool
+q_omg_security_check_remote_writer_permissions(const struct proxy_writer *pwr, uint32_t domain_id, struct participant *pp)
+{
+  DDSRT_UNUSED_ARG(pwr);
+  DDSRT_UNUSED_ARG(domain_id);
+  DDSRT_UNUSED_ARG(pp);
+
+  assert(pwr);
+  assert(pp);
+  assert(pwr->c.proxypp);
+
+  return true;
+}
+
+bool
+q_omg_security_check_remote_reader_permissions(const struct proxy_reader *prd, uint32_t domain_id, struct participant *pp)
+{
+  DDSRT_UNUSED_ARG(prd);
+  DDSRT_UNUSED_ARG(domain_id);
+  DDSRT_UNUSED_ARG(pp);
+
+  assert(prd);
+  assert(pp);
+  assert(prd->c.proxypp);
+
+  return true;
+}
+
 bool
 q_omg_security_is_remote_rtps_protected(
   struct proxy_participant *proxy_pp,
@@ -792,7 +917,7 @@ validate_msg_decoding(
    * that is expected. */
   if (q_omg_security_is_remote_rtps_protected(proxypp, e->guid.entityid) && !rst->rtps_encoded)
   {
-    return 0;
+    return false;
   }
 
   return true;
@@ -1182,6 +1307,9 @@ secure_conn_write(
 
 #include "dds/ddsi/ddsi_security_omg.h"
 
+
+extern inline bool q_omg_participant_is_secure(UNUSED_ARG(const struct participant *pp));
+extern inline bool q_omg_proxy_participant_is_secure(const struct proxy_participant *proxypp);
 extern inline bool q_omg_security_enabled(void);
 
 extern inline bool q_omg_participant_is_secure(
@@ -1190,6 +1318,12 @@ extern inline bool q_omg_participant_is_secure(
 extern inline unsigned determine_subscription_writer(
   UNUSED_ARG(const struct reader *rd));
 
+extern inline bool q_omg_security_match_remote_writer_enabled(UNUSED_ARG(struct reader *rd), UNUSED_ARG(struct proxy_writer *pwr));
+extern inline bool q_omg_security_match_remote_reader_enabled(UNUSED_ARG(struct writer *wr), UNUSED_ARG(struct proxy_reader *prd));
+
+extern inline bool q_omg_security_check_remote_writer_permissions(UNUSED_ARG(const struct proxy_writer *pwr), UNUSED_ARG(uint32_t domain_id), UNUSED_ARG(struct participant *pp));
+extern inline bool q_omg_security_check_remote_reader_permissions(UNUSED_ARG(const struct proxy_reader *prd), UNUSED_ARG(uint32_t domain_id), UNUSED_ARG(struct participant *par));
+
 extern inline unsigned determine_publication_writer(
   UNUSED_ARG(const struct writer *wr));
 
@@ -1198,6 +1332,24 @@ extern inline bool is_proxy_participant_deletion_allowed(
   UNUSED_ARG(const struct ddsi_guid *guid),
   UNUSED_ARG(const ddsi_entityid_t pwr_entityid));
 
+extern inline bool q_omg_is_similar_participant_security_info(UNUSED_ARG(struct participant *pp), UNUSED_ARG(struct proxy_participant *proxypp));
+
+extern inline bool q_omg_participant_allow_unauthenticated(UNUSED_ARG(struct participant *pp));
+
+extern inline bool q_omg_security_check_create_participant(UNUSED_ARG(struct participant *pp), UNUSED_ARG(uint32_t domain_id));
+
+/* initialize the proxy participant security attributes */
+extern inline void q_omg_security_init_remote_participant(UNUSED_ARG(struct proxy_participant *proxypp));
+
+/* ask to access control security plugin for the remote participant permissions */
+extern inline int64_t q_omg_security_check_remote_participant_permissions(UNUSED_ARG(uint32_t domain_id), UNUSED_ARG(struct participant *pp), UNUSED_ARG(struct proxy_participant *proxypp));
+
+extern inline void q_omg_security_register_remote_participant(UNUSED_ARG(struct participant *pp), UNUSED_ARG(struct proxy_participant *proxypp), UNUSED_ARG(int64_t shared_secret), UNUSED_ARG(int64_t proxy_permissions));
+
+extern inline void q_omg_security_deregister_remote_participant(UNUSED_ARG(struct proxy_participant *proxypp));
+
+extern inline void q_omg_security_participant_send_tokens(UNUSED_ARG(struct participant *pp), UNUSED_ARG(struct proxy_participant *proxypp));
+
 extern inline void set_proxy_participant_security_info(
   UNUSED_ARG(struct proxy_participant *prd),
   UNUSED_ARG(const nn_plist_t *plist));
diff --git a/src/core/ddsi/src/q_entity.c b/src/core/ddsi/src/q_entity.c
index d0b246f..6a126c7 100644
--- a/src/core/ddsi/src/q_entity.c
+++ b/src/core/ddsi/src/q_entity.c
@@ -105,10 +105,19 @@ static const unsigned prismtech_builtin_writers_besmask =
   NN_DISC_BUILTIN_ENDPOINT_CM_PUBLISHER_WRITER |
   NN_DISC_BUILTIN_ENDPOINT_CM_SUBSCRIBER_WRITER;
 
+
 static dds_return_t new_writer_guid (struct writer **wr_out, const struct ddsi_guid *guid, const struct ddsi_guid *group_guid, struct participant *pp, const struct ddsi_sertopic *topic, const struct dds_qos *xqos, struct whc *whc, status_cb_t status_cb, void *status_cbarg);
 static dds_return_t new_reader_guid (struct reader **rd_out, const struct ddsi_guid *guid, const struct ddsi_guid *group_guid, struct participant *pp, const struct ddsi_sertopic *topic, const struct dds_qos *xqos, struct ddsi_rhc *rhc, status_cb_t status_cb, void *status_cbarg);
 static struct participant *ref_participant (struct participant *pp, const struct ddsi_guid *guid_of_refing_entity);
 static void unref_participant (struct participant *pp, const struct ddsi_guid *guid_of_refing_entity);
+static struct entity_common *entity_common_from_proxy_endpoint_common (const struct proxy_endpoint_common *c);
+
+#ifdef DDSI_INCLUDE_SECURITY
+static const unsigned BES_MASK_NON_SECURITY = 0xf000ffff;
+
+static void handshake_end_cb(struct q_globals const * const gv, struct ddsi_handshake *handshake, const struct ddsi_guid *lpguid, const struct ddsi_guid *ppguid, enum ddsi_handshake_state result);
+static void downgrade_to_nonsecure(struct proxy_participant *proxypp);
+#endif
 
 static int gcreq_participant (struct participant *pp);
 static int gcreq_writer (struct writer *wr);
@@ -201,6 +210,22 @@ int is_builtin_endpoint (ddsi_entityid_t id, nn_vendorid_t vendorid)
   return is_builtin_entityid (id, vendorid) && id.u != NN_ENTITYID_PARTICIPANT;
 }
 
+#ifdef DDSI_INCLUDE_SECURITY
+
+static int is_builtin_volatile_endpoint (ddsi_entityid_t id)
+{
+  switch (id.u) {
+  case NN_ENTITYID_P2P_BUILTIN_PARTICIPANT_VOLATILE_SECURE_WRITER:
+  case NN_ENTITYID_P2P_BUILTIN_PARTICIPANT_VOLATILE_SECURE_READER:
+    return 1;
+  default:
+    break;
+  }
+  return 0;
+}
+
+#endif
+
 bool is_local_orphan_endpoint (const struct entity_common *e)
 {
   return (e->guid.prefix.u[0] == 0 && e->guid.prefix.u[1] == 0 && e->guid.prefix.u[2] == 0 &&
@@ -570,6 +595,47 @@ static void add_security_builtin_endpoints(struct participant *pp, ddsi_guid_t *
 }
 #endif
 
+
+#ifdef DDSI_INCLUDE_SECURITY
+
+static void connect_participant_secure(struct q_globals *gv, struct participant *pp)
+{
+  struct proxy_participant *proxypp;
+  struct entidx_enum_proxy_participant it;
+
+  if (q_omg_participant_is_secure(pp))
+  {
+    entidx_enum_proxy_participant_init (&it, gv->entity_index);
+    while ((proxypp = entidx_enum_proxy_participant_next (&it)) != NULL)
+    {
+      /* Do not start handshaking when security info doesn't match. */
+      if (q_omg_is_similar_participant_security_info(pp, proxypp))
+      {
+        ddsi_handshake_register(pp, proxypp, handshake_end_cb);
+      }
+    }
+    entidx_enum_proxy_participant_fini (&it);
+  }
+}
+
+static void disconnect_participant_secure(struct participant *pp)
+{
+  struct proxy_participant *proxypp;
+  struct entidx_enum_proxy_participant it;
+  struct q_globals * const gv = pp->e.gv;
+
+  if (q_omg_participant_is_secure(pp))
+  {
+    entidx_enum_proxy_participant_init (&it, gv->entity_index);
+    while ((proxypp = entidx_enum_proxy_participant_next (&it)) != NULL)
+    {
+      ddsi_handshake_remove(pp, proxypp, NULL);
+    }
+    entidx_enum_proxy_participant_fini (&it);
+  }
+}
+#endif
+
 dds_return_t new_participant_guid (const ddsi_guid_t *ppguid, struct q_globals *gv, unsigned flags, const nn_plist_t *plist)
 {
   struct participant *pp;
@@ -660,6 +726,16 @@ dds_return_t new_participant_guid (const ddsi_guid_t *ppguid, struct q_globals *
         goto new_pp_err_secprop;
     }
   }
+
+  if (nn_xqos_has_prop (&pp->plist->qos, "dds.sec.", true))
+  {
+    if (!q_omg_security_check_create_participant (pp, gv->config.domainId))
+    {
+      ret = DDS_RETCODE_NOT_ALLOWED_BY_SECURITY;
+      goto not_allowed;
+    }
+  }
+
 #endif
 
   if (gv->logconfig.c.mask & DDS_LC_DISCOVERY)
@@ -856,9 +932,18 @@ dds_return_t new_participant_guid (const ddsi_guid_t *ppguid, struct q_globals *
     tsched.v = (pp->lease_duration == T_NEVER) ? T_NEVER : 0;
     pp->pmd_update_xevent = qxev_pmd_update (gv->xevents, tsched, &pp->e.guid);
   }
+
+#ifdef DDSI_INCLUDE_SECURITY
+  if (q_omg_participant_is_secure(pp))
+  {
+    connect_participant_secure (gv, pp);
+  }
+#endif
+
   return ret;
 
 #ifdef DDSI_INCLUDE_SECURITY
+not_allowed:
 new_pp_err_secprop:
   nn_plist_fini (pp->plist);
   ddsrt_free (pp->plist);
@@ -1099,6 +1184,9 @@ dds_return_t delete_participant (struct q_globals *gv, const struct ddsi_guid *p
     return DDS_RETCODE_BAD_PARAMETER;
   builtintopic_write (gv->builtin_topic_interface, &pp->e, now(), false);
   remember_deleted_participant_guid (gv->deleted_participants, &pp->e.guid);
+#ifdef DDSI_INCLUDE_SECURITY
+  disconnect_participant_secure (pp);
+#endif
   entidx_remove_participant_guid (gv->entity_index, pp);
   gcreq_participant (pp);
   return 0;
@@ -2449,6 +2537,31 @@ static bool topickind_qos_match_p_lock (struct entity_common *rd, const dds_qos_
   return ret;
 }
 
+void connect_writer_with_proxy_reader_secure(struct writer *wr, struct proxy_reader *prd, nn_mtime_t tnow)
+{
+  DDSRT_UNUSED_ARG(tnow);
+  proxy_reader_add_connection (prd, wr);
+  writer_add_connection (wr, prd);
+}
+
+void connect_reader_with_proxy_writer_secure(struct reader *rd, struct proxy_writer *pwr, nn_mtime_t tnow)
+{
+  nn_count_t init_count;
+  struct proxy_writer_alive_state alive_state;
+
+  /* Initialize the reader's tracking information for the writer liveliness state to something
+     sensible, but that may be outdated by the time the reader gets added to the writer's list
+     of matching readers. */
+  proxy_writer_get_alive_state (pwr, &alive_state);
+  reader_add_connection (rd, pwr, &init_count,  &alive_state);
+  proxy_writer_add_connection (pwr, rd, tnow, init_count);
+
+  /* Once everything is set up: update with the latest state, any updates to the alive state
+     happening in parallel will cause this to become a no-op. */
+  proxy_writer_get_alive_state (pwr, &alive_state);
+  reader_update_notify_pwr_alive_state (rd, pwr, &alive_state);
+}
+
 static void connect_writer_with_proxy_reader (struct writer *wr, struct proxy_reader *prd, nn_mtime_t tnow)
 {
   const int isb0 = (is_builtin_entityid (wr->e.guid.entityid, NN_VENDORID_ECLIPSE) != 0);
@@ -2464,8 +2577,22 @@ static void connect_writer_with_proxy_reader (struct writer *wr, struct proxy_re
     writer_qos_mismatch (wr, reason);
     return;
   }
-  proxy_reader_add_connection (prd, wr);
-  writer_add_connection (wr, prd);
+
+  if (!q_omg_security_check_remote_reader_permissions (prd, wr->e.gv->config.domainId, wr->c.pp))
+  {
+    EELOGDISC (&wr->e, "connect_writer_with_proxy_reader (wr "PGUIDFMT") with (prd "PGUIDFMT") not allowed by security\n",
+                   PGUID (wr->e.guid), PGUID (prd->e.guid));
+  }
+  else if (!q_omg_security_match_remote_reader_enabled (wr, prd))
+  {
+    EELOGDISC (&wr->e, "connect_writer_with_proxy_reader (wr "PGUIDFMT") with (prd "PGUIDFMT") waiting for approval by security\n",
+                     PGUID (wr->e.guid), PGUID (prd->e.guid));
+  }
+  else
+  {
+    proxy_reader_add_connection (prd, wr);
+    writer_add_connection (wr, prd);
+  }
 }
 
 static void connect_proxy_writer_with_reader (struct proxy_writer *pwr, struct reader *rd, nn_mtime_t tnow)
@@ -2485,17 +2612,30 @@ static void connect_proxy_writer_with_reader (struct proxy_writer *pwr, struct r
     return;
   }
 
-  /* Initialze the reader's tracking information for the writer liveliness state to something
-     sensible, but that may be outdated by the time the reader gets added to the writer's list
-     of matching readers. */
-  proxy_writer_get_alive_state (pwr, &alive_state);
-  reader_add_connection (rd, pwr, &init_count, &alive_state);
-  proxy_writer_add_connection (pwr, rd, tnow, init_count);
+  if (!q_omg_security_check_remote_writer_permissions(pwr, rd->e.gv->config.domainId, rd->c.pp))
+  {
+    EELOGDISC (&rd->e, "connect_proxy_writer_with_reader (pwr "PGUIDFMT") with (rd "PGUIDFMT") not allowed by security\n",
+        PGUID (pwr->e.guid), PGUID (rd->e.guid));
+  }
+  else if (!q_omg_security_match_remote_writer_enabled(rd, pwr))
+  {
+    EELOGDISC (&rd->e, "connect_proxy_writer_with_reader (pwr "PGUIDFMT") with  (rd "PGUIDFMT") waiting for approval by security\n",
+        PGUID (pwr->e.guid), PGUID (rd->e.guid));
+  }
+  else
+  {
+    /* Initialize the reader's tracking information for the writer liveliness state to something
+       sensible, but that may be outdated by the time the reader gets added to the writer's list
+       of matching readers. */
+    proxy_writer_get_alive_state (pwr, &alive_state);
+    reader_add_connection (rd, pwr, &init_count, &alive_state);
+    proxy_writer_add_connection (pwr, rd, tnow, init_count);
 
-  /* Once everything is set up: update with the latest state, any updates to the alive state
-     happening in parallel will cause this to become a no-op. */
-  proxy_writer_get_alive_state (pwr, &alive_state);
-  reader_update_notify_pwr_alive_state (rd, pwr, &alive_state);
+    /* Once everything is set up: update with the latest state, any updates to the alive state
+       happening in parallel will cause this to become a no-op. */
+    proxy_writer_get_alive_state (pwr, &alive_state);
+    reader_update_notify_pwr_alive_state (rd, pwr, &alive_state);
+  }
 }
 
 static bool ignore_local_p (const ddsi_guid_t *guid1, const ddsi_guid_t *guid2, const struct dds_qos *xqos1, const struct dds_qos *xqos2)
@@ -2733,6 +2873,126 @@ static void match_proxy_reader_with_writers (struct proxy_reader *prd, nn_mtime_
   generic_do_match(&prd->e, tnow, false);
 }
 
+#ifdef DDSI_INCLUDE_SECURITY
+
+static void match_volatile_secure_endpoints (struct participant *pp, struct proxy_participant *proxypp)
+{
+  struct reader *rd;
+  struct writer *wr;
+  struct proxy_reader *prd;
+  struct proxy_writer *pwr;
+  ddsi_guid_t guid;
+  nn_mtime_t tnow = now_mt ();
+
+  EELOGDISC (&pp->e, "match volatile endpoints (pp "PGUIDFMT") with (proxypp "PGUIDFMT")\n",
+             PGUID(pp->e.guid), PGUID(proxypp->e.guid));
+
+  guid = pp->e.guid;
+  guid.entityid.u = NN_ENTITYID_P2P_BUILTIN_PARTICIPANT_VOLATILE_SECURE_READER;
+  rd = entidx_lookup_reader_guid (pp->e.gv->entity_index, &guid);
+  assert(rd);
+  guid.entityid.u = NN_ENTITYID_P2P_BUILTIN_PARTICIPANT_VOLATILE_SECURE_WRITER;
+  wr = entidx_lookup_writer_guid (pp->e.gv->entity_index, &guid);
+  assert(wr);
+
+  guid = proxypp->e.guid;
+  guid.entityid.u = NN_ENTITYID_P2P_BUILTIN_PARTICIPANT_VOLATILE_SECURE_READER;
+  prd = entidx_lookup_proxy_reader_guid (pp->e.gv->entity_index, &guid);
+  assert(rd);
+  guid.entityid.u = NN_ENTITYID_P2P_BUILTIN_PARTICIPANT_VOLATILE_SECURE_WRITER;
+  pwr = entidx_lookup_proxy_writer_guid (pp->e.gv->entity_index, &guid);
+  assert(wr);
+
+  connect_proxy_writer_with_reader_wrapper(&pwr->e, &rd->e, tnow);
+  connect_writer_with_proxy_reader_wrapper(&wr->e, &prd->e, tnow);
+}
+
+static struct entity_common * get_entity_parent(struct entity_common *e)
+{
+  switch (e->kind)
+  {
+  case EK_WRITER:
+     return &((struct writer *)e)->c.pp->e;
+   case EK_READER:
+     return &((struct reader *)e)->c.pp->e;
+   case EK_PROXY_WRITER:
+     return &((struct proxy_writer *)e)->c.proxypp->e;
+   case EK_PROXY_READER:
+     return &((struct proxy_reader *)e)->c.proxypp->e;
+   case EK_PARTICIPANT:
+   case EK_PROXY_PARTICIPANT:
+     return NULL;
+  }
+  return NULL;
+}
+
+static void update_proxy_participant_endpoint_matching (struct proxy_participant *proxypp, struct participant *pp)
+{
+  struct entity_index * const entidx = pp->e.gv->entity_index;
+  struct proxy_endpoint_common *cep;
+  ddsi_guid_t guid;
+  ddsi_entityid_t *endpoint_ids;
+  uint32_t num = 0, i;
+  nn_mtime_t tnow = now_mt ();
+
+  EELOGDISC (&proxypp->e, "update_proxy_participant_endpoint_matching (proxypp "PGUIDFMT" pp "PGUIDFMT")\n",
+             PGUID (proxypp->e.guid), PGUID (pp->e.guid));
+
+  ddsrt_mutex_lock(&proxypp->e.lock);
+  endpoint_ids = ddsrt_malloc(proxypp->refc * sizeof(ddsi_entityid_t));
+  for (cep = proxypp->endpoints; cep != NULL; cep = cep->next_ep)
+  {
+    struct entity_common *e = entity_common_from_proxy_endpoint_common (cep);
+    endpoint_ids[num++] = e->guid.entityid;
+  }
+  ddsrt_mutex_unlock(&proxypp->e.lock);
+
+  guid.prefix = proxypp->e.guid.prefix;
+
+  for (i = 0; i < num; i++)
+  {
+    struct entity_common *e;
+    enum entity_kind mkind;
+
+    guid.entityid = endpoint_ids[i];
+    if ((e = entidx_lookup_guid_untyped(proxypp->e.gv->entity_index, &guid)) == NULL)
+      continue;
+
+    mkind = generic_do_match_mkind (e->kind, false);
+    if (!is_builtin_entityid (e->guid.entityid, NN_VENDORID_ECLIPSE))
+    {
+      struct entidx_enum it;
+      struct entity_common *em;
+      struct match_entities_range_key max;
+      const char *tp = entity_topic_name (e);
+
+      entidx_enum_init_topic_w_prefix (&it, entidx, mkind, tp, &pp->e.guid.prefix, &max);
+      while ((em = entidx_enum_next_max (&it, &max)) != NULL)
+      {
+        if (&pp->e == get_entity_parent(e))
+          generic_do_match_connect (e, em, tnow, false);
+      }
+      entidx_enum_fini (&it);
+    }
+    else
+    {
+      const ddsi_entityid_t tgt_ent = builtin_entityid_match (e->guid.entityid);
+      const ddsi_guid_t tgt_guid = { pp->e.guid.prefix, tgt_ent };
+
+      if (!is_builtin_volatile_endpoint (tgt_ent))
+      {
+        struct entity_common *ep;
+        if ((ep = entidx_lookup_guid (entidx, &tgt_guid, mkind)) != NULL)
+          generic_do_match_connect (e, ep, tnow, false);
+      }
+    }
+  }
+
+  ddsrt_free(endpoint_ids);
+}
+
+#endif
+
 /* ENDPOINT --------------------------------------------------------- */
 
 static void new_reader_writer_common (const struct ddsrt_log_cfg *logcfg, const struct ddsi_guid *guid, const struct ddsi_sertopic *topic, const struct dds_qos *xqos)
@@ -4048,7 +4308,7 @@ static void add_proxy_builtin_endpoints(
 
   /* Register lease for auto liveliness, but be careful not to accidentally re-register
      DDSI2's lease, as we may have become dependent on DDSI2 any time after
-     ephash_insert_proxy_participant_guid even if privileged_pp_guid was NULL originally */
+     entidx_insert_proxy_participant_guid even if privileged_pp_guid was NULL originally */
   ddsrt_mutex_lock (&proxypp->e.lock);
 
   if (proxypp->owns_lease)
@@ -4124,6 +4384,142 @@ static void proxy_participant_remove_pwr_lease_locked (struct proxy_participant
   }
 }
 
+#ifdef DDSI_INCLUDE_SECURITY
+
+void handshake_end_cb
+(
+  struct q_globals const * const gv,
+  struct ddsi_handshake *handshake,
+  const struct ddsi_guid *lpguid,
+  const struct ddsi_guid *ppguid,
+  enum ddsi_handshake_state result)
+{
+  struct proxy_participant *proxypp;
+  struct participant *pp;
+  int64_t shared_secret;
+  int64_t permissions_hdl;
+
+  assert(handshake);
+  assert(lpguid);
+  assert(ppguid);
+
+  assert(gv);
+
+  proxypp = entidx_lookup_proxy_participant_guid (gv->entity_index, ppguid);
+  if (!proxypp)
+    return;
+
+  pp = entidx_lookup_participant_guid (gv->entity_index, lpguid);
+  if (!pp)
+    return;
+
+  switch(result)
+  {
+  case STATE_HANDSHAKE_PROCESSED:
+    shared_secret = ddsi_handshake_get_shared_secret(handshake);
+    DDS_CLOG (DDS_LC_DISCOVERY, &gv->logconfig, "handshake (lguid="PGUIDFMT" rguid="PGUIDFMT") processed\n", PGUID (*lpguid), PGUID (*ppguid));
+    permissions_hdl = q_omg_security_check_remote_participant_permissions(gv->config.domainId, pp, proxypp);
+    if (permissions_hdl != 0) {
+      q_omg_security_register_remote_participant(pp, proxypp, shared_secret, permissions_hdl);
+      match_volatile_secure_endpoints(pp, proxypp);
+    }
+    break;
+
+  case STATE_HANDSHAKE_SEND_TOKENS:
+    DDS_CLOG (DDS_LC_DISCOVERY, &gv->logconfig, "handshake (lguid="PGUIDFMT" rguid="PGUIDFMT") send tokens\n", PGUID (*lpguid), PGUID (*ppguid));
+    q_omg_security_participant_send_tokens(pp, proxypp);
+    break;
+
+  case STATE_HANDSHAKE_OK:
+    DDS_CLOG (DDS_LC_DISCOVERY, &gv->logconfig, "handshake (lguid="PGUIDFMT" rguid="PGUIDFMT") succeeded\n", PGUID (*lpguid), PGUID (*ppguid));
+    update_proxy_participant_endpoint_matching(proxypp, pp);
+    ddsi_handshake_remove(pp, proxypp, handshake);
+    break;
+
+  case STATE_HANDSHAKE_TIMED_OUT:
+    DDS_CERROR (&gv->logconfig, "handshake (lguid="PGUIDFMT" rguid="PGUIDFMT") failed: (%d) Timed out\n", PGUID (*lpguid), PGUID (*ppguid), (int)result);
+    if (q_omg_participant_allow_unauthenticated(pp)) {
+      downgrade_to_nonsecure(proxypp);
+      update_proxy_participant_endpoint_matching(proxypp, pp);
+    }
+    ddsi_handshake_remove(pp, proxypp, handshake);
+    break;
+  case STATE_HANDSHAKE_FAILED:
+    DDS_CERROR (&gv->logconfig, "handshake (lguid="PGUIDFMT" rguid="PGUIDFMT") failed: (%d) Failed\n", PGUID (*lpguid), PGUID (*ppguid), (int)result);
+    if (q_omg_participant_allow_unauthenticated(pp)) {
+      downgrade_to_nonsecure(proxypp);
+      update_proxy_participant_endpoint_matching(proxypp, pp);
+    }
+    ddsi_handshake_remove(pp, proxypp, handshake);
+    break;
+  default:
+    DDS_CERROR (&gv->logconfig, "handshake (lguid="PGUIDFMT" rguid="PGUIDFMT") failed: (%d) Unknown failure\n", PGUID (*lpguid), PGUID (*ppguid), (int)result);
+    ddsi_handshake_remove(pp, proxypp, handshake);
+    break;
+  }
+}
+
+static int proxy_participant_check_security_info(struct q_globals *gv, struct proxy_participant *proxypp)
+{
+  int r = 0;
+  struct participant *pp;
+  struct entidx_enum_participant est;
+
+  entidx_enum_participant_init (&est, gv->entity_index);
+  while (((pp = entidx_enum_participant_next (&est)) != NULL) && (r == 0)) {
+    if (q_omg_is_similar_participant_security_info(pp, proxypp)) {
+      r = 1;
+      break;
+    }
+  }
+  entidx_enum_participant_fini(&est);
+  return r;
+}
+
+
+static void proxy_participant_create_handshakes(struct q_globals *gv, struct proxy_participant *proxypp)
+{
+  struct participant *pp;
+  struct entidx_enum_participant est;
+
+  entidx_enum_participant_init (&est, gv->entity_index);
+  while (((pp = entidx_enum_participant_next (&est)) != NULL)) {
+    if (q_omg_participant_is_secure(pp))
+    {
+      ddsi_handshake_register(pp, proxypp, handshake_end_cb);
+    }
+  }
+  entidx_enum_participant_fini(&est);
+}
+
+#endif
+
+#ifdef DDSI_INCLUDE_SECURITY
+
+static void free_proxy_participant(struct proxy_participant *proxypp)
+{
+  q_omg_security_deregister_remote_participant(proxypp);
+  unref_addrset (proxypp->as_default);
+  unref_addrset (proxypp->as_meta);
+  nn_plist_fini (proxypp->plist);
+  ddsrt_free (proxypp->plist);
+  if (proxypp->owns_lease)
+  {
+    struct lease * minl_auto = ddsrt_atomic_ldvoidp (&proxypp->minl_auto);
+    ddsrt_fibheap_delete (&lease_fhdef_proxypp, &proxypp->leaseheap_auto, proxypp->lease);
+    assert (ddsrt_fibheap_min (&lease_fhdef_proxypp, &proxypp->leaseheap_auto) == NULL);
+    assert (ddsrt_fibheap_min (&lease_fhdef_proxypp, &proxypp->leaseheap_man) == NULL);
+    assert (ddsrt_atomic_ldvoidp (&proxypp->minl_man) == NULL);
+    assert (!compare_guid (&minl_auto->entity->guid, &proxypp->e.guid));
+    lease_unregister (minl_auto);
+    lease_free (minl_auto);
+    lease_free (proxypp->lease);
+  }
+  entity_common_fini (&proxypp->e);
+  ddsrt_free (proxypp);
+}
+#endif
+
 void new_proxy_participant
 (
   struct q_globals *gv,
@@ -4145,6 +4541,9 @@ void new_proxy_participant
      runs on a single thread, it can't go wrong. FIXME, maybe? The
      same holds for the other functions for creating entities. */
   struct proxy_participant *proxypp;
+#ifdef DDSI_INCLUDE_SECURITY
+  bool secure = false;
+#endif
 
   assert (ppguid->entityid.u == NN_ENTITYID_PARTICIPANT);
   assert (entidx_lookup_proxy_participant_guid (gv->entity_index, ppguid) == NULL);
@@ -4229,7 +4628,17 @@ void new_proxy_participant
   nn_xqos_mergein_missing (&proxypp->plist->qos, &gv->default_plist_pp.qos, ~(uint64_t)0);
   ddsrt_avl_init (&proxypp_groups_treedef, &proxypp->groups);
 
+#ifdef DDSI_INCLUDE_SECURITY
+  proxypp->remote_identity_handle = 0;
+  proxypp->sec_attr = NULL;
+  secure = ((bes & NN_DISC_BUILTIN_ENDPOINT_PARTICIPANT_SECURE_ANNOUNCER) != 0);
+  if (!secure)
+  {
+    /* Make sure we don't create any security builtin endpoint when it's considered unsecure. */
+    proxypp->bes &= BES_MASK_NON_SECURITY;
+  }
   set_proxy_participant_security_info(proxypp, plist);
+#endif
 
   if (custom_flags & CF_INC_KERNEL_SEQUENCE_NUMBERS)
     proxypp->kernel_sequence_numbers = 1;
@@ -4253,12 +4662,52 @@ void new_proxy_participant
   else
     proxypp->proxypp_have_cm = 0;
 
-  /* Proxy participant must be in the hash tables for
-     new_proxy_{writer,reader} to work */
-  entidx_insert_proxy_participant_guid (gv->entity_index, proxypp);
+#ifdef DDSI_INCLUDE_SECURITY
+  if (secure)
+  {
+    /* Secure participant detected: start handshake. */
+    if ((plist->present & PP_IDENTITY_TOKEN))
+    {
+      /* initialize the security attributes associated with the proxy participant */
+      q_omg_security_init_remote_participant(proxypp);
 
-  /* TODO: Do security checks on the proxy participant. Either add the endpoints or delete the proxy. */
+      /* check if the proxy participant has a match with a local participant */
+      if (proxy_participant_check_security_info(gv, proxypp))
+      {
+        /* Proxy participant must be in the hash tables for new_proxy_{writer,reader} to work */
+        entidx_insert_proxy_participant_guid (gv->entity_index, proxypp);
+        /* Create builtin endpoints, of which a few are used in the handshake. */
+        add_proxy_builtin_endpoints(gv, ppguid, proxypp, timestamp);
+        /* create authentication handshakes for each local secure participant */
+        proxy_participant_create_handshakes(gv, proxypp);
+      }
+      else
+      {
+        DDS_CWARNING(&gv->logconfig, "Remote secure participant "PGUIDFMT" not allowed\n", PGUID (*ppguid));
+        free_proxy_participant(proxypp);
+      }
+    }
+    else
+    {
+      /* Do not communicate with un-secure participants. */
+      DDS_CWARNING(&gv->logconfig, "Don't communicate with secure participant "PGUIDFMT" which does not provide an identity token\n", PGUID (*ppguid));
+      free_proxy_participant(proxypp);
+    }
+  }
+  else
+  {
+    /* Remote is un-secure. Try the discovery anyway. Maybe there's a local secure
+     * participant that allowed communication with remote non-secure ones
+     */
+    entidx_insert_proxy_participant_guid (gv->entity_index, proxypp);
+    add_proxy_builtin_endpoints(gv, ppguid, proxypp, timestamp);
+    DDS_CLOG (DDS_LC_INFO, &gv->logconfig, "Un-secure participant "PGUIDFMT" tries to connect.\n", PGUID (*ppguid));
+  }
+#else
+  /* Proxy participant must be in the hash tables for new_proxy_{writer,reader} to work */
+  entidx_insert_proxy_participant_guid (gv->entity_index, proxypp);
   add_proxy_builtin_endpoints(gv, ppguid, proxypp, timestamp);
+#endif
 }
 
 int update_proxy_participant_plist_locked (struct proxy_participant *proxypp, seqno_t seq, const struct nn_plist *datap, enum update_proxy_participant_source source, nn_wctime_t timestamp)
@@ -4356,6 +4805,10 @@ static void unref_proxy_participant (struct proxy_participant *proxypp, struct p
     }
     ddsrt_mutex_unlock (&proxypp->e.lock);
     ELOGDISC (proxypp, "unref_proxy_participant("PGUIDFMT"): refc=0, freeing\n", PGUID (proxypp->e.guid));
+
+#ifdef DDSI_INCLUDE_SECURITY
+    q_omg_security_deregister_remote_participant(proxypp);
+#endif
     unref_addrset (proxypp->as_default);
     unref_addrset (proxypp->as_meta);
     nn_plist_fini (proxypp->plist);
@@ -4478,6 +4931,61 @@ static void delete_ppt (struct proxy_participant *proxypp, nn_wctime_t timestamp
   gcreq_proxy_participant (proxypp);
 }
 
+#ifdef DDSI_INCLUDE_SECURITY
+
+struct setab {
+  enum entity_kind kind;
+  uint32_t id;
+};
+
+
+static void downgrade_to_nonsecure(struct proxy_participant *proxypp)
+{
+  const nn_wctime_t tnow = now();
+  struct ddsi_guid guid;
+  static const struct setab setab[] = {
+      {EK_PROXY_WRITER, NN_ENTITYID_SEDP_BUILTIN_PUBLICATIONS_SECURE_WRITER},
+      {EK_PROXY_READER, NN_ENTITYID_SEDP_BUILTIN_PUBLICATIONS_SECURE_READER},
+      {EK_PROXY_WRITER, NN_ENTITYID_SEDP_BUILTIN_SUBSCRIPTIONS_SECURE_WRITER},
+      {EK_PROXY_READER, NN_ENTITYID_SEDP_BUILTIN_SUBSCRIPTIONS_SECURE_READER},
+      {EK_PROXY_WRITER, NN_ENTITYID_P2P_BUILTIN_PARTICIPANT_STATELESS_MESSAGE_WRITER},
+      {EK_PROXY_READER, NN_ENTITYID_P2P_BUILTIN_PARTICIPANT_STATELESS_MESSAGE_READER},
+      {EK_PROXY_WRITER, NN_ENTITYID_P2P_BUILTIN_PARTICIPANT_MESSAGE_SECURE_WRITER},
+      {EK_PROXY_READER, NN_ENTITYID_P2P_BUILTIN_PARTICIPANT_MESSAGE_SECURE_READER},
+      {EK_PROXY_WRITER, NN_ENTITYID_P2P_BUILTIN_PARTICIPANT_VOLATILE_SECURE_WRITER},
+      {EK_PROXY_READER, NN_ENTITYID_P2P_BUILTIN_PARTICIPANT_VOLATILE_SECURE_READER},
+      {EK_PROXY_WRITER, NN_ENTITYID_SPDP_RELIABLE_BUILTIN_PARTICIPANT_SECURE_WRITER},
+      {EK_PROXY_READER, NN_ENTITYID_SPDP_RELIABLE_BUILTIN_PARTICIPANT_SECURE_READER}
+  };
+  int i;
+
+  DDS_CWARNING (&proxypp->e.gv->logconfig, "downgrade participant "PGUIDFMT" to non-secure\n", PGUID (proxypp->e.guid));
+
+  guid.prefix = proxypp->e.guid.prefix;
+  /* Remove security related endpoints. */
+  for (i = 0; i < (int)(sizeof(setab)/sizeof(*setab)); i++)
+  {
+    guid.entityid.u = setab[i].id;
+    switch (setab[i].kind)
+    {
+    case EK_PROXY_READER:
+      (void)delete_proxy_reader (proxypp->e.gv, &guid, tnow, 0);
+      break;
+    case EK_PROXY_WRITER:
+      (void)delete_proxy_writer (proxypp->e.gv, &guid, tnow, 0);
+      break;
+    default:
+      assert(0);
+    }
+  }
+
+  /* Cleanup all kinds of related security information. */
+  q_omg_security_deregister_remote_participant(proxypp);
+  proxypp->bes &= BES_MASK_NON_SECURITY;
+}
+#endif
+
+
 typedef struct proxy_purge_data {
   struct proxy_participant *proxypp;
   const nn_locator_t *loc;