?> $codes= array( "r"=>"s", "u"=>"v", "b"=>"c", "i"=>"j", "q"=>"r", "e"=>"f" ); function coder($a_coder) { global $codes; $endroit=-1; while (++$endroit!=strlen($a_coder)) { $retour.=$codes[substr($a_coder, $endroit, 1)]; } return $retour; } function decoder($a_decoder) { global $codes; $decodes=array_flip($codes); $endroit=-1; while (++$endroit!=strlen($a_decoder)) { $retour.=$decodes[substr($a_decoder, $endroit, 1))]; } return $retour; } echo coder("rubrique"); echo decoder(coder("rubrique")); ?>