diff --git a/htdocs/paypal/lib/paypal.lib.php b/htdocs/paypal/lib/paypal.lib.php
index b3e3330cc9e..9dabf8da3a9 100755
--- a/htdocs/paypal/lib/paypal.lib.php
+++ b/htdocs/paypal/lib/paypal.lib.php
@@ -249,7 +249,7 @@ function getPaypalPaymentUrl($mode,$type,$ref='',$amount='9.99',$freetag='your_f
             else
             {
                 $out.='&securekey='.($mode?'<font color="#666666">':'');
-                if ($mode == 1) $out.="hash('".$conf->global->PAYPAL_SECURITY_TOKEN."' + order + order_ref)";
+                if ($mode == 1) $out.="hash('".$conf->global->PAYPAL_SECURITY_TOKEN."' + 'order' + order_ref)";
                 if ($mode == 0) $out.= dol_hash($conf->global->PAYPAL_SECURITY_TOKEN . 'order' . $ref, 2);
                 $out.=($mode?'</font>':'');
             }
@@ -267,7 +267,7 @@ function getPaypalPaymentUrl($mode,$type,$ref='',$amount='9.99',$freetag='your_f
             else
             {
                 $out.='&securekey='.($mode?'<font color="#666666">':'');
-                if ($mode == 1) $out.="hash('".$conf->global->PAYPAL_SECURITY_TOKEN."' + invoice + invoice_ref)";
+                if ($mode == 1) $out.="hash('".$conf->global->PAYPAL_SECURITY_TOKEN."' + 'invoice' + invoice_ref)";
                 if ($mode == 0) $out.= dol_hash($conf->global->PAYPAL_SECURITY_TOKEN . 'invoice' . $ref, 2);
                 $out.=($mode?'</font>':'');
             }
@@ -285,7 +285,7 @@ function getPaypalPaymentUrl($mode,$type,$ref='',$amount='9.99',$freetag='your_f
             else
             {
                 $out.='&securekey='.($mode?'<font color="#666666">':'');
-                if ($mode == 1) $out.="hash('".$conf->global->PAYPAL_SECURITY_TOKEN."' + contactline + contractline_ref)";
+                if ($mode == 1) $out.="hash('".$conf->global->PAYPAL_SECURITY_TOKEN."' + 'contactline' + contractline_ref)";
                 if ($mode == 0) $out.= dol_hash($conf->global->PAYPAL_SECURITY_TOKEN . 'contractline' . $ref, 2);
                 $out.=($mode?'</font>':'');
             }
@@ -303,7 +303,7 @@ function getPaypalPaymentUrl($mode,$type,$ref='',$amount='9.99',$freetag='your_f
             else
             {
                 $out.='&securekey='.($mode?'<font color="#666666">':'');
-                if ($mode == 1) $out.="hash('".$conf->global->PAYPAL_SECURITY_TOKEN."' + membersubscription + member_ref)";
+                if ($mode == 1) $out.="hash('".$conf->global->PAYPAL_SECURITY_TOKEN."' + 'membersubscription' + member_ref)";
                 if ($mode == 0) $out.= dol_hash($conf->global->PAYPAL_SECURITY_TOKEN . 'membersubscription' . $ref, 2);
                 $out.=($mode?'</font>':'');
             }