Tvorba URL pre volanie portálu Tatrabanky (skrátené):

class tatrapay {

	private function make_tatra_sign( $value ) {

		// get the SHA1
		$hash = substr( mhash ( MHASH_SHA1, $value ), 0, 8 );
		$key = $this->KEY;
		
		// encrypt hash with key
		if( function_exists( 'mcrypt_module_open' ) ) { 
			// mcrypt 2.4.x
			$td = mcrypt_module_open( MCRYPT_TripleDES, "", MCRYPT_MODE_ECB, "" );
			$iv = mcrypt_create_iv( mcrypt_enc_get_iv_size ( $td ), MCRYPT_RAND );
			mcrypt_generic_init( $td, $key, $iv );
			$signature = strtoupper( bin2hex( mcrypt_generic ( $td, $hash ) ) );
			mcrypt_generic_end( $td );
		} 
		else { 
			// mcrypt 2.2.x
			$signature = strtoupper( bin2hex( mcrypt_ecb ( MCRYPT_3DES, $key, $hash, MCRYPT_ENCRYPT ) ) );
		}
		return $signature;
	}
      

	function calculate_send_sign() {

		// MID, AMT, CURR, VS, CS, RURL
		$tosign = $this->MID;
		$tosign .= $this->AMT;
		$tosign .= $this->CURR;
		$tosign .= $this->VS;
		$tosign .= $this->CS;
		$tosign .= $this->RURL;
		return ( $this->make_tatra_sign( $tosign ) );
	}

	public function user_paymentUrl() {

		$this->data = array();
		// Make sign from url data
		$sign = $this->calculate_send_sign();
		// Link to online payment
		$this->data['url'] = str_replace( '&', '&', 
			'https://moja.tatrabanka.sk/cgi-bin/e-commerce/start/e-commerce.jsp?'.
			'PT='.		urlencode( $this->PT ).			// payment type
			'&MID='.	urlencode( $this->MID ).		// merchant id
			'&AMT='.	urlencode( $this->AMT ).		// order total price
			'&CURR='.	urlencode( $this->CURR ).		// currency code
			'&VS='.		urlencode( $this->VS ).			// order uid
			'&CS='.		urlencode( $this->CS ).			// constant symbol
			'&RURL='.	urlencode( $this->RURL ).		// merchant return url
			'&IPC='.	urlencode( $this->IPC ).		// ip address, only for cardpay
			'&NAME='.	urlencode( $this->NAME ).		// user name, only for cardpay
			'&DESC='.	urlencode( $this->DESC ).		// payment description
			'&SIGN='.	$sign
		);
		return $this->data;
	}
}

https://moja.tatrabanka.sk/cgi-bin/e-commerce/start/e-commerce.jsp?
	PT=CardPay&
	MID=777&
	AMT=640.00&
	CURR=978&
	VS=0000000192&
	CS=0000000558&
	RURL=http%3A%2F%2Fwww.tubby.sk%2Ftypo3conf%2Fredirect.php&
	IPC=127.0.0.1&
	NAME=robert+gonda&
	DESC=Online_payment_tubby&
	SIGN=BC5FB82B987AE239

require_once( 'cardpay.php' );
$payment = new user_payments_cardpay();
$payment->setAmt( number_format( $this->sum, 2, '.', '' ) ); // cena objednavky
$payment->setCurr( 'EUR' ); // mena
$payment->setVs( $this->objednavka_uid ); // cislo objednavky
$url = $payment->user_paymentUrl( $conf );
$out .= '<p><a href="'.$url['url'].'" title="cardpay"><strong>Priama platba...</strong></a></p>';

Kompletný kód dostupný len po prihlásení.