Discussion :

[nazoreen]

Bonjour à tous,

Je vous soumets ici un formulaire multi-pages très sécurisé, données de session cryptées, retour impossible etc...

J'aimerais avoir vos avis, nottamment sur d'éventuels trous de sécurités.

A bientôt et merci pour les critiques et conseils.

Code :

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<?php
$key	= "motdepasse";
 
function generate_iv()
{
	$length = 8;
	$gen_pass = "";
	$gen_vars = array("0","1","2","3","4","5","6","7","8","9","A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q","R","S","T","U","V","W","X","Y","Z","a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z");
 
	$gen_numb = count($gen_vars) - 1;
 
	for ($i = 0; $i < $length; $i++)
	{
		$gen_pass .= $gen_vars[rand(0, $gen_numb)];
	}
 
	$iv = substr($gen_pass, 0, $length);
 
	return $iv ;
}
 
function val_encrypt($value,$key,$iv)
{
	$td = mcrypt_module_open(MCRYPT_BLOWFISH,"",MCRYPT_MODE_CFB,"");
 
	mcrypt_generic_init($td, $key, $iv);
	$value_encrypt = mcrypt_generic($td,$value);
	mcrypt_generic_deinit($td);
 
	return $value_encrypt;
}
 
function val_decrypt($value,$key,$iv)
{
	$td = mcrypt_module_open(MCRYPT_BLOWFISH,"",MCRYPT_MODE_CFB,"");
 
	mcrypt_generic_init($td, $key, $iv);
	$value_encrypt = mdecrypt_generic($td,$value);
	mcrypt_generic_deinit($td);
 
	return $value_encrypt;
}
 
session_start();
 
if(empty($_SESSION['forms']))
{
    $_SESSION['forms'] = array();
}
 
if (empty($_POST))
{
	if(empty($_SESSION['forms']))
	{
		$iv = generate_iv();
		$_SESSION['forms'] = array('steps' => '1','step1' => $iv,'step2' => '','step3' => '','step4' => '');
	}
 
	$security = $_SESSION['forms']['steps'];
 
	if ($security == "2" || $security == "3" || $security == "4")
	{
		echo "Retour Interdit !";
	} else {
		//echo $_SESSION['forms']['steps'];
		?>
		<form method="post" action="form.php">
			<fieldset>
				<legend>Identifiant</legend>
				<label><input type="text" name="step2" value="" /><label>
			</fieldset>
			<input type="submit" name="login0" value=">>>" /><br />
		</form>
		<?php
	}
} else if (!empty ($_POST['login0'])) {
	$security = $_SESSION['forms']['steps'];
 
	if ($security == "3" || $security == "4")
	{
		echo "Retour Interdit !";
	} else {
		$aes_step2 = val_encrypt($_POST['step2'],$key,$_SESSION['forms']['step1']);
 
		$_SESSION['forms'] = array('steps' => '2','step1' => $_SESSION['forms']['step1'],'step2' => $aes_step2,'step3' => '','step4' => '');
 
		//echo $_SESSION['forms']['steps'];
		?>
		<form method="post" action="form.php">
			<fieldset>
				<legend>Nom</legend>
				<label><input type="text" name="step3" value="" /><label>
			</fieldset>
			<input type="submit" name="login1" value=">>>" /><br />
		</form>
		<?php
	}
} else if (!empty ($_POST['login1'])) {
	$security = $_SESSION['forms']['steps'];
 
	if ($security == "4")
	{
		echo "Retour Interdit !";
	} else {
		$aes_step3 = val_encrypt($_POST['step3'],$key,$_SESSION['forms']['step1']);
 
		$_SESSION['forms'] = array('steps' => '3','step1' => $_SESSION['forms']['step1'],'step2' => $_SESSION['forms']['step2'],'step3' => $aes_step3,'step4' => '');
 
		//echo $_SESSION['forms']['steps'];
		?>
		<form method="post" action="form.php">
			<fieldset>
				<legend>Prénom</legend>
				<label><input type="text" name="step4" value="" /><label>
			</fieldset>
			<input type="submit" name="login2" value=">>>" /><br />
		</form>
		<?php
	}
} else if (!empty ($_POST['login2'])) {
	$aes_step4 = val_encrypt($_POST['step4'],$key,$_SESSION['forms']['step1']);
 
	$_SESSION['forms'] = array('steps' => '4','step1' => $_SESSION['forms']['step1'],'step2' => $_SESSION['forms']['step2'],'step3' => $_SESSION['forms']['step3'],'step4' => $aes_step4);
 
	//echo $_SESSION['forms']['steps'];
	?>
	<fieldset>
		<legend>Résumé</legend>
		<label>Identifiant : <?php echo val_decrypt($_SESSION['forms']['step2'],$key,$_SESSION['forms']['step1']); ?><label><br />
		<label>Nom : <?php echo val_decrypt($_SESSION['forms']['step3'],$key,$_SESSION['forms']['step1']); ?><label><br />
		<label>Prénom : <?php echo val_decrypt($_SESSION['forms']['step4'],$key,$_SESSION['forms']['step1']); ?><label><br />
	</fieldset>
	<?php
}
?>

[nazoreen]

J'ai oublié une chose...

Si vous vous demandez pourquoi tant de sécurité, tout simplement parce que je développe une application bancaire, le formulaire sera un peu plus complexe, nottamment avec Captcha (en première étape) et HTTPS pour la connexion à l'espace client.

La base de donnée utilise SHA1 pour le chiffrement irréversible et AES_ENCRYPT pour le reversible.

Par la suite on pourra toujours l'améliorer avec une authentification PKI.

Le formulaire simple (tel que vous le voyez) pourra être utilisé pour l'enregistrement d'un client.

A bientôt et merci.