zot 1.2

3 files changed, 270 insertions, 162 deletions

diff --git a/include/conversation.php b/include/conversation.php
index 16eacd73e..0f61eea27 100644
--- a/include/conversation.php
+++ b/include/conversation.php
@@ -363,7 +363,7 @@ function localize_item(&$item){
 
 	if(intval($item['item_obscured'])
 		&& strlen($item['body']) && (! strpos($item['body'],'data'))) {
-		$item['body']  = json_encode(crypto_encapsulate($item['body'],get_config('system','pubkey'), CRYPTO_ALGORITHM));
+		$item['body']  = z_obscure($item['body']);
 	}
 
 }
diff --git a/include/crypto.php b/include/crypto.php
index c67c4a1ef..e9fa320d3 100644
--- a/include/crypto.php
+++ b/include/crypto.php
@@ -48,27 +48,115 @@ function pkcs5_unpad($text)
 function AES256CBC_encrypt($data,$key,$iv) {
 
 	return openssl_encrypt($data,'aes-256-cbc',str_pad($key,32,"\0"),OPENSSL_RAW_DATA,str_pad($iv,16,"\0"));
-
 }
 
 function AES256CBC_decrypt($data,$key,$iv) {
 
 	return openssl_decrypt($data,'aes-256-cbc',str_pad($key,32,"\0"),OPENSSL_RAW_DATA,str_pad($iv,16,"\0"));
+}
+
+function AES128CBC_encrypt($data,$key,$iv) {
+	$key = substr($key,0,16);
+	return openssl_encrypt($data,'aes-128-cbc',str_pad($key,16,"\0"),OPENSSL_RAW_DATA,str_pad($iv,16,"\0"));
+}
+
+function AES128CBC_decrypt($data,$key,$iv) {
+	$key = substr($key,0,16);
+	return openssl_decrypt($data,'aes-128-cbc',str_pad($key,16,"\0"),OPENSSL_RAW_DATA,str_pad($iv,16,"\0"));
+}
+
+function STD_encrypt($data,$key,$iv) {
+	$key = substr($key,0,32);
+	return openssl_encrypt($data,'aes-256-cbc',str_pad($key,32,"\0"),OPENSSL_RAW_DATA,str_pad($iv,16,"\0"));
+}
+
+function STD_decrypt($data,$key,$iv) {
+	$key = substr($key,0,32);
+	return openssl_decrypt($data,'aes-256-cbc',str_pad($key,32,"\0"),OPENSSL_RAW_DATA,str_pad($iv,16,"\0"));
+}
 
+function CAST5CBC_encrypt($data,$key,$iv) {
+	$key = substr($key,0,16);
+	$iv = substr($iv,0,8);
+	return openssl_encrypt($data,'cast5-cbc',str_pad($key,16,"\0"),OPENSSL_RAW_DATA,str_pad($iv,8,"\0"));
+}
+
+function CAST5CBC_decrypt($data,$key,$iv) {
+	$key = substr($key,0,16);
+	$iv = substr($iv,0,8);
+	return openssl_decrypt($data,'cast5-cbc',str_pad($key,16,"\0"),OPENSSL_RAW_DATA,str_pad($iv,8,"\0"));
 }
 
 function crypto_encapsulate($data,$pubkey,$alg='aes256cbc') {
+	$fn = strtoupper($alg) . '_encrypt';
+	
 	if($alg === 'aes256cbc')
 		return aes_encapsulate($data,$pubkey);
 
+	return other_encapsulate($data,$pubkey,$alg);
+
+}
+
+function other_encapsulate($data,$pubkey,$alg) {
+	if(! $pubkey)
+		logger('no key. data: ' . $data);
+
+	$fn = strtoupper($alg) . '_encrypt';
+	if(function_exists($fn)) {
+
+		// A bit hesitant to use openssl_random_pseudo_bytes() as we know
+		// it has been historically targeted by US agencies for 'weakening'.
+		// It is still arguably better than trying to come up with an
+		// alternative cryptographically secure random generator.
+		// There is little point in using the optional second arg to flag the
+		// assurance of security since it is meaningless if the source algorithms
+		// have been compromised. Also none of this matters if RSA has been
+		// compromised by state actors and evidence is mounting that this has
+		// already happened.   
+
+		$key = openssl_random_pseudo_bytes(256);
+		$iv  = openssl_random_pseudo_bytes(256);
+		$result['data'] = base64url_encode($fn($data,$key,$iv),true);
+		// log the offending call so we can track it down
+		if(! openssl_public_encrypt($key,$k,$pubkey)) {
+			$x = debug_backtrace();
+			logger('RSA failed. ' . print_r($x[0],true));
+		}
+
+		$result['alg'] = $alg;
+	 	$result['key'] = base64url_encode($k,true);
+		openssl_public_encrypt($iv,$i,$pubkey);
+		$result['iv'] = base64url_encode($i,true);
+		return $result;
+	}
+	else {
+		$x = [ 'data' => $data, 'pubkey' => $pubkey, 'alg' => $alg, 'result' => $data ];
+		call_hooks('other_encapsulate', $x);
+		return $x['result'];
+	}
+}
+
+function crypto_methods() {
+
+	// 'std' is the new project standard which is aes256cbc but transmits/receives 256-byte key and iv. 
+	// aes256cbc is provided for compatibility with earlier zot implementations which assume 32-byte key and 16-byte iv. 
+	// other_encapsulate() now produces these longer keys/ivs by default so that it is difficult to guess a
+	// particular implementation or choice of underlying implementations based on the key/iv length. 
+	// The actual methods are responsible for deriving the actual key/iv from the provided parameters;
+	// possibly by truncation or segmentation - though many other methods could be used.  
+
+	$r = [ 'std', 'aes256cbc', 'aes128cbc', 'cast5cbc' ];
+	call_hooks('crypto_methods',$r);
+	return $r;
+
 }
 
 
 function aes_encapsulate($data,$pubkey) {
 	if(! $pubkey)
 		logger('aes_encapsulate: no key. data: ' . $data);
-	$key = random_string(32,RANDOM_STRING_TEXT);
-	$iv  = random_string(16,RANDOM_STRING_TEXT);
+	$key = openssl_random_pseudo_bytes(32);
+	$iv  = openssl_random_pseudo_bytes(16);
 	$result['data'] = base64url_encode(AES256CBC_encrypt($data,$key,$iv),true);
 	// log the offending call so we can track it down
 	if(! openssl_public_encrypt($key,$k,$pubkey)) {
@@ -89,6 +177,22 @@ function crypto_unencapsulate($data,$prvkey) {
 	if($alg === 'aes256cbc')
 		return aes_unencapsulate($data,$prvkey);
 
+	return other_unencapsulate($data,$prvkey,$alg);
+
+}
+
+function other_unencapsulate($data,$prvkey,$alg) {
+	$fn = strtoupper($alg) . '_decrypt';
+	if(function_exists($fn)) {
+		openssl_private_decrypt(base64url_decode($data['key']),$k,$prvkey);
+		openssl_private_decrypt(base64url_decode($data['iv']),$i,$prvkey);
+		return $fn(base64url_decode($data['data']),$k,$i);
+	}
+	else {
+		$x = [ 'data' => $data, 'prvkey' => $prvkey, 'alg' => $alg, 'result' => $data ];
+		call_hooks('other_unencapsulate',$x);
+		return $x['result'];
+	}
 }
 
 
@@ -315,7 +419,7 @@ function convert_salmon_key($key) {
 
 
 function z_obscure($s) {
-	return json_encode(crypto_encapsulate($s,get_config('system','pubkey'),CRYPTO_ALGORITHM));
+	return json_encode(crypto_encapsulate($s,get_config('system','pubkey')));
 }
 
 function z_unobscure($s) {
diff --git a/include/zot.php b/include/zot.php
index ee4836d6c..e29978908 100644
--- a/include/zot.php
+++ b/include/zot.php
@@ -110,20 +110,21 @@ function zot_get_hublocs($hash) {
  * @param string $extra
  * @returns string json encoded zot packet
  */
-function zot_build_packet($channel, $type = 'notify', $recipients = null, $remote_key = null, $secret = null, $extra = null) {
+function zot_build_packet($channel, $type = 'notify', $recipients = null, $remote_key = null, $methods = '', $secret = null, $extra = null) {
 
-	$data = array(
+	$data = [
 		'type' => $type,
-		'sender' => array(
+		'sender' => [
 			'guid' => $channel['channel_guid'],
 			'guid_sig' => base64url_encode(rsa_sign($channel['channel_guid'],$channel['channel_prvkey'])),
 			'url' => z_root(),
 			'url_sig' => base64url_encode(rsa_sign(z_root(),$channel['channel_prvkey'])),
 			'sitekey' => get_config('system','pubkey')
-		),
+		],
 		'callback' => '/post',
-		'version' => ZOT_REVISION
-	);
+		'version' => ZOT_REVISION,
+		'encryption' => crypto_methods()
+	];
 
 	if ($recipients) {
 		for ($x = 0; $x < count($recipients); $x ++)
@@ -146,14 +147,46 @@ function zot_build_packet($channel, $type = 'notify', $recipients = null, $remot
 
 	// Hush-hush ultra top-secret mode
 
-	if ($remote_key) {
-		$data = crypto_encapsulate(json_encode($data),$remote_key, CRYPTO_ALGORITHM);
+	if($remote_key) {
+		$algorithm = zot_best_algorithm($methods);
+		$data = crypto_encapsulate(json_encode($data),$remote_key, $algorithm);
 	}
 
 	return json_encode($data);
 }
 
 /**
+ * @brief choose best encryption function from those available on both sites
+ * 
+ * @param string $methods
+ *   comma separated list of encryption methods
+ * @return string first match from our site method preferences crypto_methods() array
+ * of a method which is common to both sites; or 'aes256cbc' if no matches are found.
+ */
+
+function zot_best_algorithm($methods) {
+
+	if($methods) {
+		$x = explode(',',$methods);
+		if($x) {
+			$y = crypto_methods();
+			if($y) {
+				foreach($y as $yv) {
+					$yv = trim($yv);
+					if(in_array($yv,$x)) {
+						return($yv);
+					}
+				}
+			}
+		}
+	}
+
+	return 'aes256cbc';
+}
+
+
+
+/**
  * @brief
  *
  * @see z_post_url()
@@ -167,101 +200,11 @@ function zot_zot($url, $data) {
 }
 
 /**
- * @brief Look up information about channel.
- *
- * @param string $webbie
- *   does not have to be host qualified e.g. 'foo' is treated as 'foo\@thishub'
- * @param array $channel
- *   (optional), if supplied permissions will be enumerated specifically for $channel
- * @param boolean $autofallback
- *   fallback/failover to http if https connection cannot be established. Default is true.
- *
- * @return array see z_post_url() and \ref Zotlabs::Zot::Finger "\\Zotlabs\\Zot\\Finger"
- */
-function zot_finger($webbie, $channel = null, $autofallback = true) {
-
-	if (strpos($webbie,'@') === false) {
-		$address = $webbie;
-		$host = App::get_hostname();
-	} else {
-		$address = substr($webbie,0,strpos($webbie,'@'));
-		$host = substr($webbie,strpos($webbie,'@')+1);
-		if(strpos($host,'/'))
-			$host = substr($host,0,strpos($host,'/'));
-	}
-
-	$xchan_addr = $address . '@' . $host;
-
-	if ((! $address) || (! $xchan_addr)) {
-		logger('zot_finger: no address :' . $webbie);
-		return array('success' => false);
-	}
-	logger('using xchan_addr: ' . $xchan_addr, LOGGER_DATA, LOG_DEBUG);
-
-	// potential issue here; the xchan_addr points to the primary hub.
-	// The webbie we were called with may not, so it might not be found
-	// unless we query for hubloc_addr instead of xchan_addr
-
-	$r = q("select xchan.*, hubloc.* from xchan
-			left join hubloc on xchan_hash = hubloc_hash
-			where xchan_addr = '%s' and hubloc_primary = 1 limit 1",
-		dbesc($xchan_addr)
-	);
-
-	if ($r) {
-		$url = $r[0]['hubloc_url'];
-
-		if ($r[0]['hubloc_network'] && $r[0]['hubloc_network'] !== 'zot') {
-			logger('zot_finger: alternate network: ' . $webbie);
-			logger('url: '.$url.', net: '.var_export($r[0]['hubloc_network'],true), LOGGER_DATA, LOG_DEBUG);
-			return array('success' => false);
-		}
-	} else {
-		$url = 'https://' . $host;
-	}
-
-	$rhs = '/.well-known/zot-info';
-	$https = ((strpos($url,'https://') === 0) ? true : false);
-
-	logger('zot_finger: ' . $address . ' at ' . $url, LOGGER_DEBUG);
-
-	if ($channel) {
-		$postvars = array(
-			'address'    => $address,
-			'target'     => $channel['channel_guid'],
-			'target_sig' => $channel['channel_guid_sig'],
-			'key'        => $channel['channel_pubkey']
-		);
-
-		$result = z_post_url($url . $rhs,$postvars);
-
-		if ((! $result['success']) && ($autofallback)) {
-			if ($https) {
-				logger('zot_finger: https failed. falling back to http');
-				$result = z_post_url('http://' . $host . $rhs,$postvars);
-			}
-		}
-	} else {
-		$rhs .= '?f=&address=' . urlencode($address);
-
-		$result =  z_fetch_url($url . $rhs);
-		if ((! $result['success']) && ($autofallback)) {
-			if ($https) {
-				logger('zot_finger: https failed. falling back to http');
-				$result = z_fetch_url('http://' . $host . $rhs);
-			}
-		}
-	}
-
-	if (! $result['success'])
-		logger('zot_finger: no results');
-
-	return $result;
-}
-
-/**
  * @brief Refreshes after permission changed or friending, etc.
  *
+ * The top half of this function is similar to \Zotlabs\Zot\Finger::run() and could potentially be
+ * consolidated.
+ *
  * zot_refresh is typically invoked when somebody has changed permissions of a channel and they are notified
  * to fetch new permissions via a finger/discovery operation. This may result in a new connection
  * (abook entry) being added to a local channel and it may result in auto-permissions being granted.
@@ -283,6 +226,7 @@ function zot_finger($webbie, $channel = null, $autofallback = true) {
  *
  * @returns boolean true if successful, else false
  */
+
 function zot_refresh($them, $channel = null, $force = false) {
 
 	if (array_key_exists('xchan_network', $them) && ($them['xchan_network'] !== 'zot')) {
@@ -298,7 +242,8 @@ function zot_refresh($them, $channel = null, $force = false) {
 
 	if ($them['hubloc_url']) {
 		$url = $them['hubloc_url'];
-	} else {
+	}
+	else {
 		$r = null;
 
 		// if they re-installed the server we could end up with the wrong record - pointing to the old install.
@@ -334,7 +279,7 @@ function zot_refresh($them, $channel = null, $force = false) {
 
 	$token = random_string();
 
-	$postvars = array();
+	$postvars = [];
 
 	$postvars['token'] = $token;
 
@@ -395,11 +340,13 @@ function zot_refresh($them, $channel = null, $force = false) {
 
 		if($channel) {
 			if($j['permissions']['data']) {
-				$permissions = crypto_unencapsulate(array(
+				$permissions = crypto_unencapsulate(
+					[
 					'data' => $j['permissions']['data'],
 					'key'  => $j['permissions']['key'],
 					'iv'   => $j['permissions']['iv'],
-					'alg'  => $j['permissions']['alg']),
+					'alg'  => $j['permissions']['alg']
+					],
 					$channel['channel_prvkey']);
 				if($permissions)
 					$permissions = json_decode($permissions,true);
@@ -521,12 +468,14 @@ function zot_refresh($them, $channel = null, $force = false) {
 					if($new_connection) {
 						if(! \Zotlabs\Access\Permissions::PermsCompare($new_perms,$previous_perms))
 							Zotlabs\Daemon\Master::Summon(array('Notifier','permission_create',$new_connection[0]['abook_id']));
-						Zotlabs\Lib\Enotify::submit(array(
+						Zotlabs\Lib\Enotify::submit(
+							[
 							'type'       => NOTIFY_INTRO,
 							'from_xchan' => $x['hash'],
 							'to_xchan'   => $channel['channel_hash'],
-							'link'       => z_root() . '/connedit/' . $new_connection[0]['abook_id'],
-						));
+							'link'       => z_root() . '/connedit/' . $new_connection[0]['abook_id']
+							]
+						);
 
 						if(intval($permissions['view_stream'])) {
 							if(intval(get_pconfig($channel['channel_id'],'perm_limits','send_stream') & PERMS_PENDING)
@@ -536,6 +485,7 @@ function zot_refresh($them, $channel = null, $force = false) {
 
 
 						/** If there is a default group for this channel, add this connection to it */
+
 						$default_group = $channel['channel_default_group'];
 						if($default_group) {
 							require_once('include/group.php');
@@ -581,6 +531,7 @@ function zot_refresh($them, $channel = null, $force = false) {
  * @returns array|null null if site is blacklisted or not found, otherwise an
  *  array with an hubloc record
  */
+
 function zot_gethub($arr, $multiple = false) {
 
 	if($arr['guid'] && $arr['guid_sig'] && $arr['url'] && $arr['url_sig']) {
@@ -593,7 +544,7 @@ function zot_gethub($arr, $multiple = false) {
 		$limit = (($multiple) ? '' : ' limit 1 ');
 		$sitekey = ((array_key_exists('sitekey',$arr) && $arr['sitekey']) ? " and hubloc_sitekey = '" . protect_sprintf($arr['sitekey']) . "' " : '');
 
-		$r = q("select * from hubloc
+		$r = q("select hubloc.*, site.site_crypto from hubloc left join site on hubloc_url = site_url
 				where hubloc_guid = '%s' and hubloc_guid_sig = '%s'
 				and hubloc_url = '%s' and hubloc_url_sig = '%s'
 				$sitekey $limit",
@@ -630,9 +581,10 @@ function zot_gethub($arr, $multiple = false) {
  *  * \b success boolean true or false
  *  * \b message (optional) error string only if success is false
  */
+
 function zot_register_hub($arr) {
 
-	$result = array('success' => false);
+	$result = [ 'success' => false ];
 
 	if($arr['url'] && $arr['url_sig'] && $arr['guid'] && $arr['guid_sig']) {
 
@@ -691,6 +643,7 @@ function zot_register_hub($arr) {
  *   * \e boolean \b success boolean true or false
  *   * \e string \b message (optional) error string only if success is false
  */
+
 function import_xchan($arr,$ud_flags = UPDATE_FLAGS_UPDATED, $ud_arr = null) {
 
 	call_hooks('import_xchan', $arr);
@@ -789,7 +742,8 @@ function import_xchan($arr,$ud_flags = UPDATE_FLAGS_UPDATED, $ud_arr = null) {
 			$what .= 'xchan ';
 			$changed = true;
 		}
-	} else {
+	}
+	else {
 		$import_photos = true;
 
 		if((($arr['site']['directory_mode'] === 'standalone')
@@ -825,7 +779,7 @@ function import_xchan($arr,$ud_flags = UPDATE_FLAGS_UPDATED, $ud_arr = null) {
 		$changed = true;
 	}
 
-	if ($import_photos) {
+	if($import_photos) {
 
 		require_once('include/photo/photo_driver.php');
 
@@ -834,9 +788,9 @@ function import_xchan($arr,$ud_flags = UPDATE_FLAGS_UPDATED, $ud_arr = null) {
 		$local = q("select channel_account_id, channel_id from channel where channel_hash = '%s' limit 1",
 			dbesc($xchan_hash)
 		);
-		if ($local) {
+		if($local) {
 			$ph = z_fetch_url($arr['photo'], true);
-			if ($ph['success']) {
+			if($ph['success']) {
 
 				$hash = import_channel_photo($ph['body'], $arr['photo_mimetype'], $local[0]['channel_account_id'], $local[0]['channel_id']);
 
@@ -874,11 +828,12 @@ function import_xchan($arr,$ud_flags = UPDATE_FLAGS_UPDATED, $ud_arr = null) {
 					false
 				);
 			}
-		} else {
+		}
+		else {
 			$photos = import_xchan_photo($arr['photo'], $xchan_hash);
 		}
-		if ($photos) {
-			if ($photos[4]) {
+		if($photos) {
+			if($photos[4]) {
 				// importing the photo failed somehow. Leave the photo_date alone so we can try again at a later date.
 				// This often happens when somebody joins the matrix with a bad cert.
 				$r = q("update xchan set xchan_photo_l = '%s', xchan_photo_m = '%s', xchan_photo_s = '%s', xchan_photo_mimetype = '%s'
@@ -889,7 +844,8 @@ function import_xchan($arr,$ud_flags = UPDATE_FLAGS_UPDATED, $ud_arr = null) {
 					dbesc($photos[3]),
 					dbesc($xchan_hash)
 				);
-			} else {
+			}
+			else {
 				$r = q("update xchan set xchan_photo_date = '%s', xchan_photo_l = '%s', xchan_photo_m = '%s', xchan_photo_s = '%s', xchan_photo_mimetype = '%s'
 					where xchan_hash = '%s'",
 					dbescdate(datetime_convert('UTC','UTC',$arr['photo_updated'])),
@@ -946,7 +902,8 @@ function import_xchan($arr,$ud_flags = UPDATE_FLAGS_UPDATED, $ud_arr = null) {
 				$what .= 'profile ';
 				$changed = true;
 			}
-		} else {
+		}
+		else {
 			logger('import_xchan: profile not available - hiding');
 			// they may have made it private
 			$r = q("delete from xprof where xprof_hash = '%s'",
@@ -999,16 +956,17 @@ function import_xchan($arr,$ud_flags = UPDATE_FLAGS_UPDATED, $ud_arr = null) {
  * @param array $arr - output of z_post_url()
  * @param array $outq - The queue structure attached to this request
  */
+
 function zot_process_response($hub, $arr, $outq) {
 
-	if (! $arr['success']) {
+	if(! $arr['success']) {
 		logger('zot_process_response: failed: ' . $hub);
 		return;
 	}
 
 	$x = json_decode($arr['body'], true);
 
-	if (! $x) {
+	if(! $x) {
 		logger('zot_process_response: No json from ' . $hub);
 		logger('zot_process_response: headers: ' . print_r($arr['header'],true), LOGGER_DATA, LOG_DEBUG);
 	}
@@ -1066,6 +1024,7 @@ function zot_process_response($hub, $arr, $outq) {
  *     decrypted and json decoded notify packet from remote site
  * @return array from zot_import()
  */
+
 function zot_fetch($arr) {
 
 	logger('zot_fetch: ' . print_r($arr,true), LOGGER_DATA, LOG_DEBUG);
@@ -1083,16 +1042,18 @@ function zot_fetch($arr) {
 	}
 
 	foreach($ret_hubs as $ret_hub) {
-		$data = array(
-			'type'    => 'pickup',
-			'url'     => z_root(),
-			'callback_sig' => base64url_encode(rsa_sign(z_root() . '/post',get_config('system','prvkey'))),
-			'callback' => z_root() . '/post',
-			'secret' => $arr['secret'],
-			'secret_sig' => base64url_encode(rsa_sign($arr['secret'],get_config('system','prvkey')))
-		);
 
-		$datatosend = json_encode(crypto_encapsulate(json_encode($data),$ret_hub['hubloc_sitekey'], CRYPTO_ALGORITHM));
+		$data = [
+			'type'         => 'pickup',
+			'url'          => z_root(),
+			'callback_sig' => base64url_encode(rsa_sign(z_root() . '/post', get_config('system','prvkey'))),
+			'callback'     => z_root() . '/post',
+			'secret'       => $arr['secret'],
+			'secret_sig'   => base64url_encode(rsa_sign($arr['secret'], get_config('system','prvkey')))
+		];
+
+		$algorithm = zot_best_algorithm($ret_hub['site_crypto']);
+		$datatosend = json_encode(crypto_encapsulate(json_encode($data),$ret_hub['hubloc_sitekey'], $algorithm));
 
 		$fetch = zot_zot($url,$datatosend);
 
@@ -1143,6 +1104,11 @@ function zot_import($arr, $sender_url) {
 		$data = json_decode(crypto_unencapsulate($data,get_config('system','prvkey')),true);
 	}
 
+	if(! is_array($data)) {
+		logger('decode error');
+		return array();
+	}
+
 	if(! $data['success']) {
 		if($data['message'])
 			logger('remote pickup failed: ' . $data['message']);
@@ -1168,6 +1134,12 @@ function zot_import($arr, $sender_url) {
 
 			logger('zot_import: notify: ' . print_r($i['notify'],true), LOGGER_DATA, LOG_DEBUG);
 
+			if(! is_array($i['notify'])) {
+				logger('decode error');
+				continue;
+			}
+
+
 			$hub = zot_gethub($i['notify']['sender']);
 			if((! $hub) || ($hub['hubloc_url'] != $sender_url)) {
 				logger('zot_import: potential forgery: wrong site for sender: ' . $sender_url . ' != ' . print_r($i['notify'],true));
@@ -1358,6 +1330,7 @@ function zot_import($arr, $sender_url) {
  * @param array $msg
  * @return NULL|array
  */
+
 function public_recips($msg) {
 
 	require_once('include/channel.php');
@@ -1567,6 +1540,7 @@ function allowed_public_recips($msg) {
  * @param boolean $request (optional) default false
  * @return array
  */
+
 function process_delivery($sender, $arr, $deliveries, $relay, $public = false, $request = false) {
 
 	$result = array();
@@ -1876,6 +1850,7 @@ function process_delivery($sender, $arr, $deliveries, $relay, $public = false, $
  *   * \e int \b mid
  * @param int $uid
  */
+
 function remove_community_tag($sender, $arr, $uid) {
 
 	if(! (activity_match($arr['verb'], ACTIVITY_TAG) && ($arr['obj_type'] == ACTIVITY_OBJ_TAGTERM)))
@@ -1946,6 +1921,7 @@ function remove_community_tag($sender, $arr, $uid) {
  * @param array $orig
  * @param int $uid
  */
+
 function update_imported_item($sender, $item, $orig, $uid) {
 
 	// If this is a comment being updated, remove any privacy information
@@ -1986,6 +1962,7 @@ function update_imported_item($sender, $item, $orig, $uid) {
  * @param boolean $relay
  * @return boolean|int post_id
  */
+
 function delete_imported_item($sender, $item, $uid, $relay) {
 
 	logger('delete_imported_item invoked', LOGGER_DEBUG);
@@ -2003,13 +1980,14 @@ function delete_imported_item($sender, $item, $uid, $relay) {
 		intval($uid)
 	);
 
-	if ($r) {
-		if ($r[0]['author_xchan'] === $sender['hash'] || $r[0]['owner_xchan'] === $sender['hash'] || $r[0]['source_xchan'] === $sender['hash'])
+	if($r) {
+		if($r[0]['author_xchan'] === $sender['hash'] || $r[0]['owner_xchan'] === $sender['hash'] || $r[0]['source_xchan'] === $sender['hash'])
 			$ownership_valid = true;
 
 		$post_id = $r[0]['id'];
 		$item_found = true;
-	} else {
+	}
+	else {
 
 		// perhaps the item is still in transit and the delete notification got here before the actual item did. Store it with the deleted flag set.
 		// item_store() won't try to deliver any notifications or start delivery chains if this flag is set.
@@ -2018,25 +1996,24 @@ function delete_imported_item($sender, $item, $uid, $relay) {
 
 		logger('delete received for non-existent item - storing item data.');
 
-		/** @BUG $arr is undefined here, so this is dead code */
-		if ($arr['author_xchan'] === $sender['hash'] || $arr['owner_xchan'] === $sender['hash'] || $arr['source_xchan'] === $sender['hash']) {
+		if($item['author_xchan'] === $sender['hash'] || $item['owner_xchan'] === $sender['hash'] || $item['source_xchan'] === $sender['hash']) {
 			$ownership_valid = true;
-			$item_result = item_store($arr);
+			$item_result = item_store($item);
 			$post_id = $item_result['item_id'];
 		}
 	}
 
-	if ($ownership_valid === false) {
+	if($ownership_valid === false) {
 		logger('delete_imported_item: failed: ownership issue');
 		return false;
 	}
 
 	require_once('include/items.php');
 
-	if ($item_found) {
-		if (intval($r[0]['item_deleted'])) {
+	if($item_found) {
+		if(intval($r[0]['item_deleted'])) {
 			logger('delete_imported_item: item was already deleted');
-			if (! $relay)
+			if(! $relay)
 				return false;
 
 			// This is a bit hackish, but may have to suffice until the notification/delivery loop is optimised
@@ -2147,6 +2124,7 @@ function process_mail_delivery($sender, $arr, $deliveries) {
  *   * \e string \b hash a xchan_hash
  * @param array $arr
  */
+
 function process_rating_delivery($sender, $arr) {
 
 	logger('process_rating_delivery: ' . print_r($arr,true));
@@ -2206,6 +2184,7 @@ function process_rating_delivery($sender, $arr) {
  * @param array $arr
  * @param array $deliveries (unused)
  */
+
 function process_profile_delivery($sender, $arr, $deliveries) {
 
 	logger('process_profile_delivery', LOGGER_DEBUG);
@@ -2302,6 +2281,7 @@ function check_location_move($sender_hash,$locations) {
  * @param boolean $absolute (optional) default false
  * @return array
  */
+
 function sync_locations($sender, $arr, $absolute = false) {
 
 	$ret = array();
@@ -2549,7 +2529,7 @@ function zot_encode_locations($channel) {
 			if(intval($channel['channel_removed']) && $hub['hubloc_url'] === z_root())
 				$hub['hubloc_deleted'] = 1;
 
-			$ret[] = array(
+			$ret[] = [
 				'host'     => $hub['hubloc_host'],
 				'address'  => $hub['hubloc_addr'],
 				'primary'  => (intval($hub['hubloc_primary']) ? true : false),
@@ -2558,7 +2538,7 @@ function zot_encode_locations($channel) {
 				'callback' => $hub['hubloc_callback'],
 				'sitekey'  => $hub['hubloc_sitekey'],
 				'deleted'  => (intval($hub['hubloc_deleted']) ? true : false)
-			);
+			];
 		}
 	}
 
@@ -2575,6 +2555,7 @@ function zot_encode_locations($channel) {
  * @param number $suppress_update default 0
  * @return boolean $updated if something changed
  */
+
 function import_directory_profile($hash, $profile, $addr, $ud_flags = UPDATE_FLAGS_UPDATED, $suppress_update = 0) {
 
 	logger('import_directory_profile', LOGGER_DEBUG);
@@ -2709,6 +2690,7 @@ function import_directory_profile($hash, $profile, $addr, $ud_flags = UPDATE_FLA
  * @param string $hash
  * @param array $keywords
  */
+
 function import_directory_keywords($hash, $keywords) {
 
 	$existing = array();
@@ -2753,6 +2735,7 @@ function import_directory_keywords($hash, $keywords) {
  * @param string $addr
  * @param int $flags (optional) default 0
  */
+
 function update_modtime($hash, $guid, $addr, $flags = 0) {
 
 	$dirmode = intval(get_config('system', 'directory_mode'));
@@ -2785,6 +2768,7 @@ function update_modtime($hash, $guid, $addr, $flags = 0) {
  * @param string $pubkey
  * @return boolean true if updated or inserted
  */
+
 function import_site($arr, $pubkey) {
 	if( (! is_array($arr)) || (! $arr['url']) || (! $arr['url_sig']))
 		return false;
@@ -2852,7 +2836,7 @@ function import_site($arr, $pubkey) {
 	$site_location = htmlspecialchars($arr['location'],ENT_COMPAT,'UTF-8',false);
 	$site_realm = htmlspecialchars($arr['realm'],ENT_COMPAT,'UTF-8',false);
 	$site_project = htmlspecialchars($arr['project'],ENT_COMPAT,'UTF-8',false);
-	$site_crypto = ((array_key_exists('encryption',$arr)) ? implode(',', htmlspecialchars($arr['encryption'],ENT_COMPAT,'UTF-8',false)) : '');
+	$site_crypto = ((array_key_exists('encryption',$arr) && is_array($arr['encryption'])) ? htmlspecialchars(implode(',',$arr['encryption']),ENT_COMPAT,'UTF-8',false) : '');
 	$site_version = ((array_key_exists('version',$arr)) ? htmlspecialchars($arr['version'],ENT_COMPAT,'UTF-8',false) : '');
 
 	// You can have one and only one primary directory per realm.
@@ -2947,6 +2931,7 @@ function import_site($arr, $pubkey) {
  * @param array $packet (optional) default null
  * @param boolean $groups_changed (optional) default false
  */
+
 function build_sync_packet($uid = 0, $packet = null, $groups_changed = false) {
 
 	if(get_config('system','server_role') === 'basic')
@@ -2982,7 +2967,7 @@ function build_sync_packet($uid = 0, $packet = null, $groups_changed = false) {
 	if(intval($channel['channel_removed']))
 		return;
 
-	$h = q("select * from hubloc where hubloc_hash = '%s' and hubloc_deleted = 0",
+	$h = q("select hubloc.*, site.site_crypto from hubloc left join site on site_url = hubloc_url where hubloc_hash = '%s' and hubloc_deleted = 0",
 		dbesc($channel['channel_hash'])
 	);
 
@@ -3069,7 +3054,7 @@ function build_sync_packet($uid = 0, $packet = null, $groups_changed = false) {
 
 	foreach($synchubs as $hub) {
 		$hash = random_string();
-		$n = zot_build_packet($channel,'notify',$env_recips,$hub['hubloc_sitekey'],$hash);
+		$n = zot_build_packet($channel,'notify',$env_recips,$hub['hubloc_sitekey'],$hub['site_crypto'],$hash);
 		queue_insert(array(
 			'hash'       => $hash,
 			'account_id' => $channel['channel_account_id'],
@@ -3095,6 +3080,7 @@ function build_sync_packet($uid = 0, $packet = null, $groups_changed = false) {
  * @param array $deliveries
  * @return array
  */
+
 function process_channel_sync_delivery($sender, $arr, $deliveries) {
 
 	if(get_config('system','server_role') === 'basic')
@@ -3569,6 +3555,7 @@ function process_channel_sync_delivery($sender, $arr, $deliveries) {
  *   * \e string \b xchan_url
  * @return string
  */
+
 function get_rpost_path($observer) {
 	if(! $observer)
 		return '';
@@ -3584,6 +3571,7 @@ function get_rpost_path($observer) {
  * @param array $x
  * @return boolean|string return false or a hash
  */
+
 function import_author_zot($x) {
 
 	$hash = make_xchan_hash($x['guid'],$x['guid_sig']);
@@ -3623,6 +3611,7 @@ function import_author_zot($x) {
  * @param array $data
  * @return array
  */
+
 function zot_reply_message_request($data) {
 	$ret = array('success' => false);
 
@@ -3659,7 +3648,7 @@ function zot_reply_message_request($data) {
 	if ($messages) {
 		$env_recips = null;
 
-		$r = q("select * from hubloc where hubloc_hash = '%s' and hubloc_error = 0 and hubloc_deleted = 0",
+		$r = q("select hubloc.*, site.site_crypto from hubloc left join site on hulob_url = site_url where hubloc_hash = '%s' and hubloc_error = 0 and hubloc_deleted = 0",
 			dbesc($sender_hash)
 		);
 		if (! $r) {
@@ -3681,7 +3670,7 @@ function zot_reply_message_request($data) {
 			 * create a notify packet and drop the actual message packet in the queue for pickup
 			 */
 
-			$n = zot_build_packet($c[0],'notify',$env_recips,(($private) ? $hub['hubloc_sitekey'] : null),$hash,array('message_id' => $data['message_id']));
+			$n = zot_build_packet($c[0],'notify',$env_recips,(($private) ? $hub['hubloc_sitekey'] : null),$hub['site_crypto'],$hash,array('message_id' => $data['message_id']));
 
 			queue_insert(array(
 				'hash'       => $hash,
@@ -3918,7 +3907,12 @@ function zotinfo($arr) {
 			$permissions['connected'] = true;
 	}
 
-	$ret['permissions'] = (($ztarget && $zkey) ? crypto_encapsulate(json_encode($permissions),$zkey, CRYPTO_ALGORITHM) : $permissions);
+	// encrypt this with the default aes256cbc since we cannot be sure at this point which
+	// algorithms are preferred for communications with the remote site; notably
+	// because ztarget refers to an xchan and we don't necessarily know the origination
+	// location.
+
+	$ret['permissions'] = (($ztarget && $zkey) ? crypto_encapsulate(json_encode($permissions),$zkey) : $permissions);
 
 	if($permissions['view_profile'])
 		$ret['profile']  = $profile;
@@ -3948,6 +3942,8 @@ function zotinfo($arr) {
 		$ret['site']['directory_url'] = z_root() . '/dirsearch';
 
 
+	$ret['site']['encryption'] = crypto_methods();
+
 	// hide detailed site information if you're off the grid
 
 	if($dirmode != DIRECTORY_MODE_STANDALONE) {
@@ -3988,14 +3984,14 @@ function zotinfo($arr) {
 					$visible_plugins[] = $rr['aname'];
 		}
 
-		$ret['site']['plugins'] = $visible_plugins;
-		$ret['site']['sitehash'] = get_config('system','location_hash');
-		$ret['site']['sitename'] = get_config('system','sitename');
-		$ret['site']['sellpage'] = get_config('system','sellpage');
-		$ret['site']['location'] = get_config('system','site_location');
-		$ret['site']['realm'] = get_directory_realm();
-		$ret['site']['project'] = Zotlabs\Lib\System::get_platform_name() . ' ' . Zotlabs\Lib\System::get_server_role();
-		$ret['site']['version'] = Zotlabs\Lib\System::get_project_version();
+		$ret['site']['plugins']    = $visible_plugins;
+		$ret['site']['sitehash']   = get_config('system','location_hash');
+		$ret['site']['sitename']   = get_config('system','sitename');
+		$ret['site']['sellpage']   = get_config('system','sellpage');
+		$ret['site']['location']   = get_config('system','site_location');
+		$ret['site']['realm']      = get_directory_realm();
+		$ret['site']['project']    = Zotlabs\Lib\System::get_platform_name() . ' ' . Zotlabs\Lib\System::get_server_role();
+		$ret['site']['version']    = Zotlabs\Lib\System::get_project_version();
 
 	}
 
@@ -4322,7 +4318,15 @@ function zot_reply_pickup($data) {
 		}
 	}
 
-	$encrypted = crypto_encapsulate(json_encode($ret),$sitekey, CRYPTO_ALGORITHM);
+	// this is a bit of a hack because we don't have the hubloc_url here, only the callback url.
+	// worst case is we'll end up using aes256cbc if they've got a different post endpoint
+
+	$x = q("select site_crypto from site where site_url = '%s' limit 1",
+		dbesc(str_replace('/post','',$data['callback']))
+	);
+	$algorithm = zot_best_algorithm(($x) ? $x[0]['site_crypto'] : '');
+
+	$encrypted = crypto_encapsulate(json_encode($ret),$sitekey,$algorithm);
 	json_return_and_die($encrypted);
 
 	/* pickup: end */