diff --git a/ykval-common.php b/ykval-common.php
index 50bb2e0..ae204cc 100644
--- a/ykval-common.php
+++ b/ykval-common.php
@@ -219,11 +219,12 @@ function KSMdecryptOTP($urls) {
   return $ret;
 } // End decryptOTP
 
-function sendResp($status, $apiKey = '', $extra = null) {
+function sendResp($status, $context, $apiKey = '', $extra = null) {
   if ($status == null) {
     $status = S_BACKEND_ERROR;
   }
 
+
   $a['status'] = $status;
   $a['t'] = getUTCTimeStamp();
   if ($extra){
@@ -242,8 +243,8 @@ function sendResp($status, $apiKey = '', $extra = null) {
   $str .= "\r\n";
 
   global $ykval_common_log;
-  $ykval_common_log->log(LOG_INFO, "Response: " . $str .
-			 " (at " . date("c") . " " . microtime() . ")");
+  $ykval_common_log->log(LOG_INFO, "Context=" . $context . " Response: " . $str .
+    " (at " . date("c") . " " . microtime() . ")");
 
   echo $str;
 }
diff --git a/ykval-sync.php b/ykval-sync.php
index ddf40fe..2f3111d 100644
--- a/ykval-sync.php
+++ b/ykval-sync.php
@@ -4,11 +4,12 @@ require_once 'ykval-config.php';
 require_once 'ykval-synclib.php';
 
 $apiKey = '';
+$context = 'sync';
 
 header("content-type: text/plain");
 
 if(empty($_SERVER['QUERY_STRING'])) {
-  sendResp(S_MISSING_PARAMETER, $apiKey);
+  sendResp(S_MISSING_PARAMETER, $context, $apiKey);
   exit;
 }
 
@@ -21,7 +22,7 @@ $sync = new SyncLib('ykval-sync:synclib');
 $sync->addField('ip', $_SERVER['REMOTE_ADDR']);
 
 if (! $sync->isConnected()) {
-  sendResp(S_BACKEND_ERROR, $apiKey);
+  sendResp(S_BACKEND_ERROR, $context, $apiKey);
   exit;
  }
 
@@ -41,7 +42,7 @@ foreach ($baseParams['__YKVAL_ALLOWED_SYNC_POOL__'] as $server) {
 }
 if (!$allowed) {
   $myLog->log(LOG_NOTICE, 'Operation not allowed from IP ' . $_SERVER['REMOTE_ADDR']);
-  sendResp(S_OPERATION_NOT_ALLOWED, $apiKey);
+  sendResp(S_OPERATION_NOT_ALLOWED, $context, $apiKey);
   exit;
  }
 
@@ -67,7 +68,7 @@ foreach ($syncParams as $param=>$value) {
   $value = getHttpVal($param, Null);
   if ($value==Null) {
     $myLog->log(LOG_NOTICE, "Received request with parameter[s] (" . $param . ") missing value");
-    sendResp(S_MISSING_PARAMETER, '');
+    sendResp(S_MISSING_PARAMETER, $context, $apiKey);
     exit;
   }
   $syncParams[$param]=$value;
@@ -88,7 +89,7 @@ $sync->addField('otp', $syncParams['otp']);
 foreach (array('modified') as $param) {
   if (preg_match("/^[0-9]+$/", $syncParams[$param])==0) {
     $myLog->log(LOG_NOTICE, 'Input parameters ' . $param . ' not correct');
-    sendResp(S_MISSING_PARAMETER, $apiKey);
+    sendResp(S_MISSING_PARAMETER, $context, $apiKey);
     exit;
   }
 }
@@ -96,7 +97,7 @@ foreach (array('modified') as $param) {
 foreach (array('yk_counter', 'yk_use', 'yk_high', 'yk_low') as $param) {
   if (preg_match("/^(-1|[0-9]+)$/", $syncParams[$param])==0) {
     $myLog->log(LOG_NOTICE, 'Input parameters ' . $param . ' not correct');
-    sendResp(S_MISSING_PARAMETER, $apiKey);
+    sendResp(S_MISSING_PARAMETER, $context, $apiKey);
     exit;
   }
 }
@@ -112,7 +113,7 @@ $yk_publicname = $syncParams['yk_publicname'];
 $localParams = $sync->getLocalParams($yk_publicname);
 if (!$localParams) {
   $myLog->log(LOG_NOTICE, 'Invalid Yubikey ' . $yk_publicname);
-  sendResp(S_BACKEND_ERROR, $apiKey);
+  sendResp(S_BACKEND_ERROR, $context, $apiKey);
   exit;
  }
 
@@ -179,6 +180,6 @@ $extra=array('modified'=>$localParams['modified'],
 	     'yk_high'=>$localParams['yk_high'],
 	     'yk_low'=>$localParams['yk_low']);
 
-sendResp(S_OK, '', $extra);
+sendResp(S_OK, $context, $apiKey, $extra);
 
 ?>
diff --git a/ykval-verify.php b/ykval-verify.php
index 21516c6..a5a5944 100644
--- a/ykval-verify.php
+++ b/ykval-verify.php
@@ -4,6 +4,7 @@ require_once 'ykval-config.php';
 require_once 'ykval-synclib.php';
 
 $apiKey = '';
+$context = 'verify';
 
 header("content-type: text/plain");
 
@@ -56,7 +57,7 @@ if ($protocol_version>=2.0) {
   /* Nonce is required from protocol 2.0 */
   if(!$nonce) {
     $myLog->log(LOG_NOTICE, 'Nonce is missing and protocol version >= 2.0');
-    sendResp(S_MISSING_PARAMETER);
+    sendResp(S_MISSING_PARAMETER, $context);
     exit;
   }
 }
@@ -90,49 +91,49 @@ if (!isset($timeout) || $timeout == '') {
 
 if ($otp == '') {
   $myLog->log(LOG_NOTICE, 'OTP is missing');
-  sendResp(S_MISSING_PARAMETER);
+  sendResp(S_MISSING_PARAMETER, $context);
   exit;
 }
 
 if (strlen($otp) < TOKEN_LEN || strlen ($otp) > OTP_MAX_LEN) {
   $myLog->log(LOG_NOTICE, 'Incorrect OTP length: ' . $otp);
-  sendResp(S_BAD_OTP);
+  sendResp(S_BAD_OTP, $context);
   exit;
 }
 
 if (preg_match("/^[cbdefghijklnrtuv]+$/", $otp)==0) {
   $myLog->log(LOG_NOTICE, 'Invalid OTP: ' . $otp);
-  sendResp(S_BAD_OTP);
+  sendResp(S_BAD_OTP, $context);
   exit;
 }
 
 if (preg_match("/^[0-9]+$/", $client)==0){
   $myLog->log(LOG_NOTICE, 'id provided in request must be an integer');
-  sendResp(S_MISSING_PARAMETER);
+  sendResp(S_MISSING_PARAMETER, $context);
   exit;
 }
 
 if ($timeout && preg_match("/^[0-9]+$/", $timeout)==0) {
   $myLog->log(LOG_NOTICE, 'timeout is provided but not correct');
-  sendResp(S_MISSING_PARAMETER);
+  sendResp(S_MISSING_PARAMETER, $context);
   exit;
 }
 
 if (isset($nonce) && preg_match("/^[A-Za-z0-9]+$/", $nonce)==0) {
   $myLog->log(LOG_NOTICE, 'NONCE is provided but not correct');
-  sendResp(S_MISSING_PARAMETER);
+  sendResp(S_MISSING_PARAMETER, $context);
   exit;
 }
 
 if (isset($nonce) && (strlen($nonce) < 16 || strlen($nonce) > 40)) {
   $myLog->log(LOG_NOTICE, 'Nonce too short or too long');
-  sendResp(S_MISSING_PARAMETER);
+  sendResp(S_MISSING_PARAMETER, $context);
   exit;
 }
 
 if ($sl && (preg_match("/^[0-9]+$/", $sl)==0 || ($sl<0 || $sl>100))) {
   $myLog->log(LOG_NOTICE, 'SL is provided but not correct');
-  sendResp(S_MISSING_PARAMETER);
+  sendResp(S_MISSING_PARAMETER, $context);
   exit;
 }
 
@@ -143,7 +144,7 @@ if ($sl && (preg_match("/^[0-9]+$/", $sl)==0 || ($sl<0 || $sl>100))) {
 //
 if ($client <= 0) {
   $myLog->log(LOG_NOTICE, 'Client ID is missing');
-  sendResp(S_MISSING_PARAMETER);
+  sendResp(S_MISSING_PARAMETER, $context);
   exit;
 }
 
@@ -156,14 +157,14 @@ $sync->addField('ip', $_SERVER['REMOTE_ADDR']);
 $sync->addField('otp', $otp);
 
 if (! $sync->isConnected()) {
-  sendResp(S_BACKEND_ERROR);
+  sendResp(S_BACKEND_ERROR, $context);
   exit;
  }
 
 $cd=$sync->getClientData($client);
 if(!$cd) {
   $myLog->log(LOG_NOTICE, 'Invalid client id ' . $client);
-  sendResp(S_NO_SUCH_CLIENT);
+  sendResp(S_NO_SUCH_CLIENT, $context);
   exit;
  }
 $myLog->log(LOG_DEBUG,"Client data:", $cd);
@@ -189,7 +190,7 @@ if ($h != '') {
   // Compare it
   if ($hmac != $h) {
     $myLog->log(LOG_DEBUG, 'client hmac=' . $h . ', server hmac=' . $hmac);
-    sendResp(S_BAD_SIGNATURE, $apiKey);
+    sendResp(S_BAD_SIGNATURE, $context, $apiKey);
     exit;
   }
 }
@@ -206,7 +207,7 @@ if ($protocol_version<2.0) {
 //
 $urls = otp2ksmurls ($otp, $client);
 if (!is_array($urls)) {
-  sendResp(S_BACKEND_ERROR, $apiKey);
+  sendResp(S_BACKEND_ERROR, $context, $apiKey);
   exit;
 }
 
@@ -214,7 +215,7 @@ if (!is_array($urls)) {
 //
 $otpinfo = KSMdecryptOTP($urls);
 if (!is_array($otpinfo)) {
-  sendResp(S_BAD_OTP, $apiKey);
+  sendResp(S_BAD_OTP, $context, $apiKey);
   exit;
 }
 $myLog->log(LOG_DEBUG, "Decrypted OTP:", $otpinfo);
@@ -226,14 +227,14 @@ $yk_publicname=$devId;
 $localParams = $sync->getLocalParams($yk_publicname);
 if (!$localParams) {
   $myLog->log(LOG_NOTICE, 'Invalid Yubikey ' . $yk_publicname);
-  sendResp(S_BACKEND_ERROR, $apiKey);
+  sendResp(S_BACKEND_ERROR, $context, $apiKey);
   exit;
  }
 
 $myLog->log(LOG_DEBUG, "Auth data:", $localParams);
 if ($localParams['active'] != 1) {
   $myLog->log(LOG_NOTICE, 'De-activated Yubikey ' . $devId);
-  sendResp(S_BAD_OTP, $apiKey);
+  sendResp(S_BAD_OTP, $context, $apiKey);
   exit;
 }
 
@@ -253,7 +254,7 @@ $otpParams=array('modified'=>time(),
 if ($sync->countersEqual($localParams, $otpParams) &&
     $localParams['nonce']==$otpParams['nonce']) {
   $myLog->log(LOG_WARNING, 'Replayed request');
-  sendResp(S_REPLAYED_REQUEST, $apiKey, $extra);
+  sendResp(S_REPLAYED_REQUEST, $context, $apiKey, $extra);
   exit;
  }
 
@@ -262,7 +263,7 @@ if ($sync->countersHigherThanOrEqual($localParams, $otpParams)) {
   $sync->log(LOG_WARNING, 'replayed OTP: Local counters higher');
   $sync->log(LOG_WARNING, 'replayed OTP: Local counters ', $localParams);
   $sync->log(LOG_WARNING, 'replayed OTP: Otp counters ', $otpParams);
-  sendResp(S_REPLAYED_OTP, $apiKey, $extra);
+  sendResp(S_REPLAYED_OTP, $context, $apiKey, $extra);
   exit;
  }
 
@@ -270,7 +271,7 @@ if ($sync->countersHigherThanOrEqual($localParams, $otpParams)) {
 
 if(!$sync->updateDbCounters($otpParams)) {
   $myLog->log(LOG_CRIT, "Failed to update yubikey counters in database");
-  sendResp(S_BACKEND_ERROR, $apiKey);
+  sendResp(S_BACKEND_ERROR, $context, $apiKey);
   exit;
  }
 
@@ -278,7 +279,7 @@ if(!$sync->updateDbCounters($otpParams)) {
 
 if (!$sync->queue($otpParams, $localParams)) {
   $myLog->log(LOG_CRIT, "ykval-verify:critical:failed to queue sync requests");
-  sendResp(S_BACKEND_ERROR, $apiKey);
+  sendResp(S_BACKEND_ERROR, $context, $apiKey);
   exit;
  }
 
@@ -310,11 +311,11 @@ if($syncres==False) {
    there were not enough answers */
   $myLog->log(LOG_WARNING, "ykval-verify:notice:Sync failed");
   if ($nr_valid_answers!=$nr_answers) {
-    sendResp(S_REPLAYED_OTP, $apiKey, $extra);
+    sendResp(S_REPLAYED_OTP, $context, $apiKey, $extra);
     exit;
   } else {
     $extra['sl']=$sl_success_rate;
-    sendResp(S_NOT_ENOUGH_ANSWERS, $apiKey, $extra);
+    sendResp(S_NOT_ENOUGH_ANSWERS, $context, $apiKey, $extra);
     exit;
   }
  }
@@ -362,7 +363,7 @@ if ($sessionCounter == $seenSessionCounter && $sessionUse > $seenSessionUse) {
   if ($deviation > TS_ABS_TOLERANCE && $percent > TS_REL_TOLERANCE) {
     $myLog->log(LOG_NOTICE, "OTP failed phishing test");
     if (0) {
-      sendResp(S_DELAYED_OTP, $apiKey, $extra);
+      sendResp(S_DELAYED_OTP, $context, $apiKey, $extra);
       exit;
     }
   }
@@ -378,6 +379,6 @@ if ($timestamp==1){
   $extra['sessionuse'] = $sessionUse;
  }
 
-sendResp(S_OK, $apiKey, $extra);
+sendResp(S_OK, $context, $apiKey, $extra);
 
 ?>