Introduce shadow logins

server/conf.php

@@ -38,4 +38,26 @@ $ADMIN_MODE=true;
   this value with existings masterkeys, they will unusable !
  */
 $PKDBF2_LEVEL=1000;
+
+/*
+  This is a security feature : It protects from database dump
+  and database purge without authentication.
+  When get all entries, instead of returning logins/passwords,
+  it returns "shadow logins". These are random values.
+  Shadow logins must be encrypted using masterkey and salt
+  (to generate a unique PKDBF2 derivation) that result in an access tokens.
+  With this access token, user has the right to get
+  encrypted login/password values and remove them.
+  It's a kind of challenge.
+
+  This option is backward compatible with old version < 0.6, but
+  once activated it cannot be reverted as access tokens will be
+  generated for all values. So, if you want to test it, make
+  a copy of your databases before !
+
+  For now it's deactivated because it requires high cpu bandwidth
+  (one derivation + two decryption for each password !). When
+  standard crypto API will be stable it will be enabled by default.
+*/
+$USE_SHADOW_LOGINS=0;
 ?>