diff --git a/boot.php b/boot.php
index 224eba1f45..6d09c647e9 100644
--- a/boot.php
+++ b/boot.php
@@ -23,6 +23,7 @@ use Friendica\Core\Config;
 use Friendica\Core\PConfig;
 use Friendica\Core\Protocol;
 use Friendica\Core\System;
+use Friendica\Core\Session;
 use Friendica\Database\DBA;
 use Friendica\Model\Contact;
 use Friendica\Model\Term;
@@ -426,14 +427,8 @@ function remote_user($uid = null)
 		return false;
 	}
 
-	if (!is_null($uid) && !empty($_SESSION['remote'])) {
-		/// @todo replace it with this:
-		// if (!empty($_SESSION['remote'][$uid])) ...
-		foreach ($_SESSION['remote'] as $visitor) {
-			if ($visitor['uid'] == $uid) {
-				return $visitor['cid'];
-			}
-		}
+	if (!is_null($uid)) {
+		return Session::getVisitorContactIDForUserID($uid);
 	} elseif (is_null($uid) && !empty($_SESSION['visitor_id'])) {
 		return intval($_SESSION['visitor_id']);
 	}
diff --git a/include/items.php b/include/items.php
index 25c857f115..c5d8fc023d 100644
--- a/include/items.php
+++ b/include/items.php
@@ -362,14 +362,8 @@ function drop_item($id, $return = '')
 	$contact_id = 0;
 
 	// check if logged in user is either the author or owner of this item
-
-	if (!empty($_SESSION['remote'])) {
-		foreach ($_SESSION['remote'] as $visitor) {
-			if ($visitor['uid'] == $item['uid'] && $visitor['cid'] == $item['contact-id']) {
-				$contact_id = $visitor['cid'];
-				break;
-			}
-		}
+	if (remote_user($item['uid']) == $item['contact-id']) {
+		$contact_id = $item['contact-id'];
 	}
 
 	if ((local_user() == $item['uid']) || $contact_id) {
diff --git a/mod/cal.php b/mod/cal.php
index 05ad314b03..b77abaa828 100644
--- a/mod/cal.php
+++ b/mod/cal.php
@@ -113,13 +113,8 @@ function cal_content(App $a)
 	$owner_uid = intval($a->data['user']['uid']);
 	$nick = $a->data['user']['nickname'];
 
-	if (!empty($_SESSION['remote']) && is_array($_SESSION['remote'])) {
-		foreach ($_SESSION['remote'] as $v) {
-			if ($v['uid'] == $a->profile['profile_uid']) {
-				$contact_id = $v['cid'];
-				break;
-			}
-		}
+	if (!empty(remote_user($a->profile['profile_uid']))) {
+		$contact_id = remote_user($a->profile['profile_uid']);
 	}
 
 	$groups = [];
diff --git a/mod/dfrn_poll.php b/mod/dfrn_poll.php
index d805bcfd49..fa0cf1037e 100644
--- a/mod/dfrn_poll.php
+++ b/mod/dfrn_poll.php
@@ -114,7 +114,7 @@ function dfrn_poll_init(App $a)
 						$_SESSION['remote'] = [];
 					}
 
-					$_SESSION['remote'][$r[0]['uid']] = ['cid' => $r[0]['id'], 'uid' => $r[0]['uid']];
+					$_SESSION['remote'][$r[0]['uid']] = $r[0]['id'];
 
 					$_SESSION['visitor_id'] = $r[0]['id'];
 					$_SESSION['visitor_home'] = $r[0]['url'];
@@ -521,7 +521,8 @@ function dfrn_poll_content(App $a)
 						$_SESSION['remote'] = [];
 					}
 
-					$_SESSION['remote'][$r[0]['uid']] = ['cid' => $r[0]['id'], 'uid' => $r[0]['uid']];
+					$_SESSION['remote'][$r[0]['uid']] = $r[0]['id'];
+
 					$_SESSION['visitor_id'] = $r[0]['id'];
 					$_SESSION['visitor_home'] = $r[0]['url'];
 					$_SESSION['visitor_visiting'] = $r[0]['uid'];
diff --git a/mod/item.php b/mod/item.php
index 8bc394bcb9..5ffee86a06 100644
--- a/mod/item.php
+++ b/mod/item.php
@@ -348,18 +348,8 @@ function item_post(App $a) {
 	if (local_user() && ((local_user() == $profile_uid) || $allow_comment)) {
 		$self = true;
 		$author = DBA::selectFirst('contact', [], ['uid' => local_user(), 'self' => true]);
-	} elseif (remote_user()) {
-		if (!empty($_SESSION['remote']) && is_array($_SESSION['remote'])) {
-			foreach ($_SESSION['remote'] as $v) {
-				if ($v['uid'] == $profile_uid) {
-					$contact_id = $v['cid'];
-					break;
-				}
-			}
-		}
-		if ($contact_id) {
-			$author = DBA::selectFirst('contact', [], ['id' => $contact_id]);
-		}
+	} elseif (!empty(remote_user($profile_uid))) {
+		$author = DBA::selectFirst('contact', [], ['id' => remote_user($profile_uid)]);
 	}
 
 	if (DBA::isResult($author)) {
diff --git a/mod/photos.php b/mod/photos.php
index 50f40b248c..06abade5e9 100644
--- a/mod/photos.php
+++ b/mod/photos.php
@@ -154,14 +154,12 @@ function photos_post(App $a)
 
 	if (local_user() && (local_user() == $page_owner_uid)) {
 		$can_post = true;
-	} elseif ($community_page && remote_user($page_owner_uid)) {
+	} elseif ($community_page && !empty(remote_user($page_owner_uid))) {
 		$contact_id = remote_user($page_owner_uid);
 
-		if ($contact_id > 0) {
-			if (DBA::exists('contact', ['id' => $contact_id, 'uid' => $page_owner_uid, 'blocked' => false, 'pending' => false])) {
-				$can_post = true;
-				$visitor = $contact_id;
-			}
+		if (DBA::exists('contact', ['id' => $contact_id, 'uid' => $page_owner_uid, 'blocked' => false, 'pending' => false])) {
+			$can_post = true;
+			$visitor = $contact_id;
 		}
 	}
 
@@ -883,50 +881,27 @@ function photos_content(App $a)
 
 	if (local_user() && (local_user() == $owner_uid)) {
 		$can_post = true;
-	} else {
-		if ($community_page && remote_user()) {
-			if (is_array($_SESSION['remote'])) {
-				foreach ($_SESSION['remote'] as $v) {
-					if ($v['uid'] == $owner_uid) {
-						$contact_id = $v['cid'];
-						break;
-					}
-				}
-			}
+	} elseif ($community_page && !empty(remote_user($owner_uid))) {
+		$contact_id = remote_user($owner_uid);
+		$contact = DBA::selectFirst('contact', [], ['id' => $contact_id, 'uid' => $owner_uid, 'blocked' => false, 'pending' => false]);
 
-			if ($contact_id) {
-				$contact = DBA::selectFirst('contact', [], ['id' => $contact_id, 'uid' => $owner_uid, 'blocked' => false, 'pending' => false]);
-
-				if (DBA::isResult($contact)) {
-					$can_post = true;
-					$remote_contact = true;
-					$visitor = $contact_id;
-				}
-			}
+		if (DBA::isResult($contact)) {
+			$can_post = true;
+			$remote_contact = true;
+			$visitor = $contact_id;
 		}
 	}
 
 	$groups = [];
 
 	// perhaps they're visiting - but not a community page, so they wouldn't have write access
-	if (remote_user() && !$visitor) {
-		$contact_id = 0;
-		if (is_array($_SESSION['remote'])) {
-			foreach ($_SESSION['remote'] as $v) {
-				if ($v['uid'] == $owner_uid) {
-					$contact_id = $v['cid'];
-					break;
-				}
-			}
-		}
+	if (!empty(remote_user($owner_uid)) && !$visitor) {
+		$contact_id = remote_user($owner_uid);
+		$groups = Group::getIdsByContactId($contact_id);
 
-		if ($contact_id) {
-			$groups = Group::getIdsByContactId($contact_id);
+		$contact = DBA::selectFirst('contact', [], ['id' => $contact_id, 'uid' => $owner_uid, 'blocked' => false, 'pending' => false]);
 
-			$contact = DBA::selectFirst('contact', [], ['id' => $contact_id, 'uid' => $owner_uid, 'blocked' => false, 'pending' => false]);
-
-			$remote_contact = DBA::isResult($contact);
-		}
+		$remote_contact = DBA::isResult($contact);
 	}
 
 	if (!$remote_contact && local_user()) {
diff --git a/mod/redir.php b/mod/redir.php
index 1df7060fa6..6b492473a0 100644
--- a/mod/redir.php
+++ b/mod/redir.php
@@ -66,20 +66,11 @@ function redir_init(App $a) {
 			// with the local contact. Otherwise the local user would ask the local contact
 			// for authentification everytime he/she is visiting a profile page of the local
 			// contact.
-			if ($host == $remotehost
-				&& !empty($_SESSION['remote'])
-				&& is_array($_SESSION['remote']))
-			{
-				foreach ($_SESSION['remote'] as $v) {
-					if (!empty($v['uid']) && !empty($v['cid']) &&
-					    $v['uid'] == Session::get('visitor_visiting') &&
-					    $v['cid'] == Session::get('visitor_id')) {
-						// Remote user is already authenticated.
-						$target_url = defaults($url, $contact_url);
-						Logger::log($contact['name'] . " is already authenticated. Redirecting to " . $target_url, Logger::DEBUG);
-						$a->redirect($target_url);
-					}
-				}
+			if (($host == $remotehost) && (remote_user(Session::get('visitor_visiting')) == Session::get('visitor_id'))) {
+				// Remote user is already authenticated.
+				$target_url = defaults($url, $contact_url);
+				Logger::log($contact['name'] . " is already authenticated. Redirecting to " . $target_url, Logger::DEBUG);
+				$a->redirect($target_url);
 			}
 		}
 
diff --git a/mod/videos.php b/mod/videos.php
index 9e19ecf117..62ecd0c378 100644
--- a/mod/videos.php
+++ b/mod/videos.php
@@ -154,44 +154,26 @@ function videos_content(App $a)
 
 	if ((local_user()) && (local_user() == $owner_uid)) {
 		$can_post = true;
-	} elseif ($community_page && remote_user()) {
-		if (!empty($_SESSION['remote'])) {
-			foreach ($_SESSION['remote'] as $v) {
-				if ($v['uid'] == $owner_uid) {
-					$contact_id = $v['cid'];
-					break;
-				}
-			}
-		}
+	} elseif ($community_page && !empty(remote_user($owner_uid))) {
+		$contact_id = remote_user($owner_uid);
 
-		if ($contact_id > 0) {
-			$r = q("SELECT `uid` FROM `contact` WHERE `blocked` = 0 AND `pending` = 0 AND `id` = %d AND `uid` = %d LIMIT 1",
-				intval($contact_id),
-				intval($owner_uid)
-			);
+		$r = q("SELECT `uid` FROM `contact` WHERE `blocked` = 0 AND `pending` = 0 AND `id` = %d AND `uid` = %d LIMIT 1",
+			intval($contact_id),
+			intval($owner_uid)
+		);
 
-			if (DBA::isResult($r)) {
-				$can_post = true;
-				$remote_contact = true;
-				$visitor = $contact_id;
-			}
+		if (DBA::isResult($r)) {
+			$can_post = true;
+			$remote_contact = true;
+			$visitor = $contact_id;
 		}
 	}
 
 	$groups = [];
 
 	// perhaps they're visiting - but not a community page, so they wouldn't have write access
-	if (remote_user() && (!$visitor)) {
-		$contact_id = 0;
-
-		if (!empty($_SESSION['remote'])) {
-			foreach($_SESSION['remote'] as $v) {
-				if($v['uid'] == $owner_uid) {
-					$contact_id = $v['cid'];
-					break;
-				}
-			}
-		}
+	if (!empty(remote_user($owner_uid)) && !$visitor) {
+		$contact_id = remote_user($owner_uid);
 
 		if ($contact_id > 0) {
 			$groups = Group::getIdsByContactId($contact_id);
diff --git a/mod/wall_attach.php b/mod/wall_attach.php
index c4ee33bd18..096439fa74 100644
--- a/mod/wall_attach.php
+++ b/mod/wall_attach.php
@@ -43,35 +43,21 @@ function wall_attach_post(App $a) {
 	$page_owner_cid   = $r[0]['id'];
 	$community_page   = (($r[0]['page-flags'] == User::PAGE_FLAGS_COMMUNITY) ? true : false);
 
-	if ((local_user()) && (local_user() == $page_owner_uid)) {
+	if (local_user() && (local_user() == $page_owner_uid)) {
 		$can_post = true;
-	} else {
-		if ($community_page && remote_user()) {
-			$contact_id = 0;
+	} elseif ($community_page && !empty(remote_user($page_owner_uid))) {
+		$contact_id = remote_user($page_owner_uid);
+		$r = q("SELECT `uid` FROM `contact` WHERE `blocked` = 0 AND `pending` = 0 AND `id` = %d AND `uid` = %d LIMIT 1",
+			intval($contact_id),
+			intval($page_owner_uid)
+		);
 
-			if (is_array($_SESSION['remote'])) {
-				foreach ($_SESSION['remote'] as $v) {
-					if ($v['uid'] == $page_owner_uid) {
-						$contact_id = $v['cid'];
-						break;
-					}
-				}
-			}
-
-			if ($contact_id > 0) {
-				$r = q("SELECT `uid` FROM `contact` WHERE `blocked` = 0 AND `pending` = 0 AND `id` = %d AND `uid` = %d LIMIT 1",
-					intval($contact_id),
-					intval($page_owner_uid)
-				);
-
-				if (DBA::isResult($r)) {
-					$can_post = true;
-				}
-			}
+		if (DBA::isResult($r)) {
+			$can_post = true;
 		}
 	}
 
-	if (! $can_post) {
+	if (!$can_post) {
 		if ($r_json) {
 			echo json_encode(['error' => L10n::t('Permission denied.')]);
 			exit();
diff --git a/mod/wall_upload.php b/mod/wall_upload.php
index a245ca739c..0848c05906 100644
--- a/mod/wall_upload.php
+++ b/mod/wall_upload.php
@@ -74,34 +74,21 @@ function wall_upload_post(App $a, $desktopmode = true)
 
 	if ((local_user()) && (local_user() == $page_owner_uid)) {
 		$can_post = true;
-	} else {
-		if ($community_page && remote_user()) {
-			$contact_id = 0;
-			if (is_array($_SESSION['remote'])) {
-				foreach ($_SESSION['remote'] as $v) {
-					if ($v['uid'] == $page_owner_uid) {
-						$contact_id = $v['cid'];
-						break;
-					}
-				}
-			}
+	} elseif ($community_page && !empty(remote_user($page_owner_uid))) {
+		$contact_id = remote_user($page_owner_uid);
 
-			if ($contact_id) {
-				$r = q("SELECT `uid` FROM `contact`
-					WHERE `blocked` = 0 AND `pending` = 0
-					AND `id` = %d AND `uid` = %d LIMIT 1",
-					intval($contact_id),
-					intval($page_owner_uid)
-				);
-				if (DBA::isResult($r)) {
-					$can_post = true;
-					$visitor = $contact_id;
-				}
-			}
+		$r = q("SELECT `uid` FROM `contact`
+			WHERE `blocked` = 0 AND `pending` = 0
+			AND `id` = %d AND `uid` = %d LIMIT 1",
+			intval($contact_id),
+			intval($page_owner_uid)
+		);
+		if (DBA::isResult($r)) {
+			$can_post = true;
+			$visitor = $contact_id;
 		}
 	}
 
-
 	if (!$can_post) {
 		if ($r_json) {
 			echo json_encode(['error' => L10n::t('Permission denied.')]);
diff --git a/src/Core/Session.php b/src/Core/Session.php
index 9927fca189..8e6e4c4577 100644
--- a/src/Core/Session.php
+++ b/src/Core/Session.php
@@ -120,7 +120,7 @@ class Session
 			'my_url'        => $a->getBaseURL() . '/profile/' . $user_record['nickname'],
 			'my_address'    => $user_record['nickname'] . '@' . substr($a->getBaseURL(), strpos($a->getBaseURL(), '://') + 3),
 			'addr'          => defaults($_SERVER, 'REMOTE_ADDR', '0.0.0.0'),
-			'remote'	=> []
+			'remote'	=> [],
 		]);
 
 		$remote_contacts = DBA::select('contact', ['id', 'uid'], ['nurl' => Strings::normaliseLink($_SESSION['my_url']), 'rel' => [Contact::FOLLOWER, Contact::FRIEND], 'self' => false]);
@@ -129,9 +129,7 @@ class Session
 				continue;
 			}
 
-			/// @todo Change it to this format to save space
-			// $_SESSION['remote'][$contact['uid']] = $contact['id'];
-			$_SESSION['remote'][$contact['uid']] = ['cid' => $contact['id'], 'uid' => $contact['uid']];
+			$_SESSION['remote'][$contact['uid']] = $contact['id'];
 		}
 		DBA::close($remote_contacts);
 
@@ -216,4 +214,34 @@ class Session
 			}
 		}
 	}
+
+	/**
+	 * Returns contact ID for given user ID
+	 *
+	 * @param integer $uid User ID
+	 * @return integer Contact ID of visitor for given user ID
+	 */
+	public static function getVisitorContactIDForUserID($uid)
+	{
+		if (empty($_SESSION['remote'][$uid])) {
+			return false;
+		}
+
+		return $_SESSION['remote'][$uid];
+	}
+
+	/**
+	 * Returns User ID for given contact ID of the visitor
+	 *
+	 * @param integer $cid Contact ID
+	 * @return integer User ID for given contact ID of the visitor
+	 */
+	public static function getUserIDForVisitorContactID($cid)
+	{
+		if (empty($_SESSION['remote'])) {
+			return false;
+		}
+
+		return array_search($cid, $_SESSION['remote']);
+	}
 }
diff --git a/src/Model/Profile.php b/src/Model/Profile.php
index 290b6d3490..69e73fc80b 100644
--- a/src/Model/Profile.php
+++ b/src/Model/Profile.php
@@ -248,15 +248,10 @@ class Profile
 	 */
 	public static function getByNickname($nickname, $uid = 0, $profile_id = 0)
 	{
-		if (remote_user($uid) && !empty($_SESSION['remote'])) {
-			foreach ($_SESSION['remote'] as $visitor) {
-				if ($visitor['uid'] == $uid) {
-					$contact = DBA::selectFirst('contact', ['profile-id'], ['id' => $visitor['cid']]);
-					if (DBA::isResult($contact)) {
-						$profile_id = $contact['profile-id'];
-					}
-					break;
-				}
+		if (!empty(remote_user($uid))) {
+			$contact = DBA::selectFirst('contact', ['profile-id'], ['id' => remote_user($uid)]);
+			if (DBA::isResult($contact)) {
+				$profile_id = $contact['profile-id'];
 			}
 		}
 
@@ -1130,7 +1125,7 @@ class Profile
 				continue;
 			}
 
-			$_SESSION['remote'][$contact['uid']] = ['cid' => $contact['id'], 'uid' => $contact['uid']];
+			$_SESSION['remote'][$contact['uid']] = $contact['id'];
 		}
 
 		$a->contact = $visitor;
diff --git a/src/Object/Post.php b/src/Object/Post.php
index 36be9c4e6b..afb55a0212 100644
--- a/src/Object/Post.php
+++ b/src/Object/Post.php
@@ -14,8 +14,8 @@ use Friendica\Core\L10n;
 use Friendica\Core\Logger;
 use Friendica\Core\PConfig;
 use Friendica\Core\Protocol;
-use Friendica\Core\Renderer;
 use Friendica\Core\Session;
+use Friendica\Core\Renderer;
 use Friendica\Database\DBA;
 use Friendica\Model\Contact;
 use Friendica\Model\Item;
@@ -71,13 +71,8 @@ class Post extends BaseObject
 		$this->setTemplate('wall');
 		$this->toplevel = $this->getId() == $this->getDataValue('parent');
 
-		if (!empty($_SESSION['remote']) && is_array($_SESSION['remote'])) {
-			foreach ($_SESSION['remote'] as $visitor) {
-				if ($visitor['cid'] == $this->getDataValue('contact-id')) {
-					$this->visiting = true;
-					break;
-				}
-			}
+		if (!empty(Session::getUserIDForVisitorContactID($this->getDataValue('contact-id')))) {
+			$this->visiting = true;
 		}
 
 		$this->writable = $this->getDataValue('writable') || $this->getDataValue('self');