"1012",
        "VK_VERSION"     => "008",
        "VK_SND_ID"      => "uid100049",
        "VK_STAMP"       => "67253",
        "VK_AMOUNT"      => "31.2",
        "VK_CURR"        => "EUR",
        "VK_REF"         => "672535",
        "VK_MSG"         => "Order nr. 67253",
        "VK_RETURN"      => "https://romet.vm-backend.dev.elkdata.ee/payment/callback/order/bank",
        "VK_CANCEL"      => "https://romet.vm-backend.dev.elkdata.ee/payment/callback/order/bank",
        "VK_DATETIME"    => "2022-06-22T10:49:51+0300",
        "VK_LANG"        => "EST",
        "VK_ACC"         => "EE171010123456789017",
        "VK_NAME"        => "Veebimajutus",
        "VK_ENCODING"    => "UTF-8"
);
// STEP 3. Generate data to be signed
// ==================================
// Data to be signed is in the form of XXXYYYYY where XXX is 3 char
// zero padded length of the value and YYY the value itself
// NB! LHV expects symbol count, not byte count with UTF-8,
// so use `mb_strlen` instead of `strlen` to detect the length of a string
$data = str_pad (mb_strlen($fields["VK_SERVICE"], "UTF-8"), 3, "0", STR_PAD_LEFT) . $fields["VK_SERVICE"] .    /* 1012 */
        str_pad (mb_strlen($fields["VK_VERSION"], "UTF-8"), 3, "0", STR_PAD_LEFT) . $fields["VK_VERSION"] .    /* 008 */
        str_pad (mb_strlen($fields["VK_SND_ID"], "UTF-8"),  3, "0", STR_PAD_LEFT) . $fields["VK_SND_ID"] .     /* uid100049 */
        str_pad (mb_strlen($fields["VK_STAMP"], "UTF-8"),   3, "0", STR_PAD_LEFT) . $fields["VK_STAMP"] .      /* 67253 */
        str_pad (mb_strlen($fields["VK_AMOUNT"], "UTF-8"),  3, "0", STR_PAD_LEFT) . $fields["VK_AMOUNT"] .     /* 31.2 */
        str_pad (mb_strlen($fields["VK_CURR"], "UTF-8"),    3, "0", STR_PAD_LEFT) . $fields["VK_CURR"] .       /* EUR */
        str_pad (mb_strlen($fields["VK_REF"], "UTF-8"),     3, "0", STR_PAD_LEFT) . $fields["VK_REF"] .        /* 672535 */
        str_pad (mb_strlen($fields["VK_MSG"], "UTF-8"),     3, "0", STR_PAD_LEFT) . $fields["VK_MSG"] .        /* Order nr. 67253 */
        str_pad (mb_strlen($fields["VK_RETURN"], "UTF-8"),  3, "0", STR_PAD_LEFT) . $fields["VK_RETURN"] .     /* https://romet.vm-backend.dev.elkdata.ee/payment/callback/order/bank */
        str_pad (mb_strlen($fields["VK_CANCEL"], "UTF-8"),  3, "0", STR_PAD_LEFT) . $fields["VK_CANCEL"] .     /* https://romet.vm-backend.dev.elkdata.ee/payment/callback/order/bank */
        str_pad (mb_strlen($fields["VK_DATETIME"], "UTF-8"), 3, "0", STR_PAD_LEFT) . $fields["VK_DATETIME"];    /* 2022-06-22T10:49:51+0300 */
/* $data = "0041012003008009uid1000490056725300431.2003EUR006672535015Order nr. 67253067https://romet.vm-backend.dev.elkdata.ee/payment/callback/order/bank067https://romet.vm-backend.dev.elkdata.ee/payment/callback/order/bank0242022-06-22T10:49:51+0300"; */
// STEP 4. Sign the data with RSA-SHA1 to generate MAC code
// ========================================================
openssl_sign ($data, $signature, $private_key, OPENSSL_ALGO_SHA1);
/* FBk1dL7uLz2dZnVMm0sYHwZqWviFY7gYBph2OzA7afa4PfCCpPZwVkIuFAFqj+YHc9p5OQiC5XhYqHdmpneb3vQeRwpej4MySP1lXr4nxlPRP3DV51dHeUqwwHVldg/2g0TGhmFZFCtrZNNzEVxvPKy3fj06VXj3nBpSgmlwaeg0Gn4nLTmDGuS37Ad8A3i3JkudBartZhb+KIjN4EskcREB7kwjSzQafaPH7VHVKMim2DLeUpnJnk8J+XXfaXW/RTZU6pzc8gqS9TANNpJBcEfJP03Ynh5d4COxwHSObpVeiHRrZZY9AV7hWdcymXLW/q+q80vQcgYHqD/WFYykJQ== */
$fields["VK_MAC"] = base64_encode($signature);
// STEP 5. Generate POST form with payment data that will be sent to the bank
// ==========================================================================
?>
        
        Makse teostamise näidisrakendus "LHV"