Довольный Айтишникъ

server {
server_name host1.ru;
listen 123.123.123.123;
listen 123.123.123.123 ssl;
ssl on;
ssl_certificate /path/cert.crt;
ssl_certificate_key /path/cert.key;

location / {
....
}
}

server {
server_name host2.ru;
listen 123.123.123.123;
listen 123.123.123.123 ssl;
ssl on;
ssl_certificate /path/other_cert.crt;
ssl_certificate_key /path/other_cert.key;

location / {
....
}
}

define("SALT","gfklhjr09j5FDGfkj49llkrjltreGuxLWQtKweKEMV4");
define("PASSWORD","ejhjkerht9348hhjkehtkjer");

function encode($String, $Password,$Salt) {
    $StrLen = strlen($String);
    $Seq = $Password;
    $Gamma = '';
    while (strlen($Gamma)<$StrLen)
    {
        $Seq = pack("H*",sha1($Gamma.$Seq.$Salt)); 
        $Gamma.=substr($Seq,0,8);
    }
    return $String^$Gamma;
}

$s='this is test string';
$enc=encode($s,PASSWORD,SALT);
$dec=encode($enc,PASSWORD,SALT);

echo 'Original string: '.$s.'<br>';
echo 'Encrypted string: '.base64_encode($enc).'<br>';
echo 'Decrypted string: '.$dec.'<br>';

WHERE
(currency = 'usd' and price > x1 and price < x2) or
(currency = 'rub' and price > y1 and price < y2)