"1111",
        "VK_VERSION"     => "008",
        "VK_SND_ID"      => "HP",
        "VK_REC_ID"      => "uid100052",
        "VK_STAMP"       => "1",
        "VK_T_NO"        => "16364",
        "VK_AMOUNT"      => "4938.14",
        "VK_CURR"        => "EUR",
        "VK_REC_ACC"     => "",
        "VK_REC_NAME"    => "",
        "VK_SND_ACC"     => "EE152200221234567897",
        "VK_SND_NAME"    => "Tõõgera Leõpäöldi",
        "VK_REF"         => "13",
        "VK_MSG"         => "My cool payment",
        "VK_T_DATETIME"  => "2021-02-18T09:07:51+0000",
        "VK_ENCODING"    => "UTF-8",
        "VK_LANG"        => "EST",
        "VK_MAC"         => "EUSsEsICBqWsBhqlTh++MT4wvVBKzb3Ejp6VsgjEyz4K6RW+x6G6Wk3ActoNcwFhzL16gMkNL1D4wvBoiDCDdjfc3dR67ro8RA5JXRf1Na3RPGIvPDJrHG6FHBylZFZm6FWLRFs4T7ayHmBGdOOA5YwNP9bpyhqrzCdcQeOLKySADy3WLZz6hiciz8i0IxhHJIgBkW9U6LrPgL/S1J2uHsme2R2JPBRq1O2U1AEIHwCSzOBzAHqrFXIS3Ewa1M3G9b8MgbTXD6rMlusSe2T33LLZk2lkNtxsUQmP7OSBWjwXYrhWPRfRj3ozQI/YljQ6eG9zAVnghStl1ZKadpshZQ==",
        "VK_AUTO"        => "N"
);
// STEP 3. Generate data to be verified
// ====================================
// Data to be verified is in the form of XXXYYYYY where XXX is 3 char
// zero padded length of the value and YYY the value itself
// NB! Swedbank 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) . $fields["VK_SERVICE"] .    /* 1111 */
        str_pad (mb_strlen($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) . $fields["VK_SND_ID"] .     /* HP */
        str_pad (mb_strlen($fields["VK_REC_ID"], "UTF-8"),    3, "0", STR_PAD_LEFT) . $fields["VK_REC_ID"] .     /* uid100052 */
        str_pad (mb_strlen($fields["VK_STAMP"], "UTF-8"),     3, "0", STR_PAD_LEFT) . $fields["VK_STAMP"] .      /* 1 */
        str_pad (mb_strlen($fields["VK_T_NO"], "UTF-8"),      3, "0", STR_PAD_LEFT) . $fields["VK_T_NO"] .       /* 16364 */
        str_pad (mb_strlen($fields["VK_AMOUNT"], "UTF-8"),    3, "0", STR_PAD_LEFT) . $fields["VK_AMOUNT"] .     /* 4938.14 */
        str_pad (mb_strlen($fields["VK_CURR"], "UTF-8"),      3, "0", STR_PAD_LEFT) . $fields["VK_CURR"] .       /* EUR */
        str_pad (mb_strlen($fields["VK_REC_ACC"], "UTF-8"),   3, "0", STR_PAD_LEFT) . $fields["VK_REC_ACC"] .    /*  */
        str_pad (mb_strlen($fields["VK_REC_NAME"], "UTF-8"),  3, "0", STR_PAD_LEFT) . $fields["VK_REC_NAME"] .   /*  */
        str_pad (mb_strlen($fields["VK_SND_ACC"], "UTF-8"),   3, "0", STR_PAD_LEFT) . $fields["VK_SND_ACC"] .    /* EE152200221234567897 */
        str_pad (mb_strlen($fields["VK_SND_NAME"], "UTF-8"),  3, "0", STR_PAD_LEFT) . $fields["VK_SND_NAME"] .   /* Tõõgera Leõpäöldi */
        str_pad (mb_strlen($fields["VK_REF"], "UTF-8"),       3, "0", STR_PAD_LEFT) . $fields["VK_REF"] .        /* 13 */
        str_pad (mb_strlen($fields["VK_MSG"], "UTF-8"),       3, "0", STR_PAD_LEFT) . $fields["VK_MSG"] .        /* My cool payment */
        str_pad (mb_strlen($fields["VK_T_DATETIME"], "UTF-8"), 3, "0", STR_PAD_LEFT) . $fields["VK_T_DATETIME"];  /* 2021-02-18T09:07:51+0000 */
/* $data = "0041111003008002HP009uid1000520011005163640074938.14003EUR000000020EE152200221234567897017Tõõgera Leõpäöldi00213015My cool payment0242021-02-18T09:07:51+0000"; */
// STEP 4. Verify the data with RSA-SHA1
// =====================================
if (openssl_verify ($data, base64_decode($fields["VK_MAC"]), $public_key) !== 1) {
    $signatureVerified = false;
}else{
    $signatureVerified = true;
}
// STEP 5. Display output of the received payment
// ==============================================
?>
    Payment results
    Payment: 
    Signature: