Trustly/Api/signed.php
public function useMerchantPrivateKey($cert) {
		if($cert !== FALSE) {
			$this->merchant_privatekey = openssl_pkey_get_private($cert);
			return TRUE;
		}
		return FALSE;
	}
public function useMerchantPrivateKey($cert) {
		if($cert !== FALSE) {
			$this->merchant_privatekey = openssl_pkey_get_private($cert);
			return TRUE;
		}
		return FALSE;
	}
public function useMerchantPrivateKey ( $ cert ) { if ( $ cert !== FALSE ) { $ this -> merchant_privatekey = openssl_pkey_get_private ( $ cert ) ; return TRUE ; } return FALSE ; }
Use this RSA private key for signing outgoing requests.

@see https://trustly.com/en/developer/api#/signature

@param string $cert Loaded private RSA key as a string
Use this RSA private key for signing outgoing requests .