How does the UnionPay payment interface automatically call back the url of the UnionPay payment interface of the front desk merchant?

PHP, how to call the payment interface of UnionPay?

PHP calls UnionPay payment interface//Find the interface file-level dll file provided by ICBC before the industrial and commercial payment interface.

//Provide public key encryption of order signature data to the designated page of ICBC.

//Organize the data string to be signed.

$src= .$ infomer[meracct； Merid;

$com=newcom(ICBCEBANKUTIL .B2CUtil

$ RC = $ com-Initialize(windows windows windows windows

$ssrc=$com-signC($src，strlen($ src))； //Order signature data

$RC=$com-verifySignC($src，strlen($src)，$ssrc，strlen($ ssrc))；

$ cert = $ com-getCert( 1)； //mall certificate public key

//Store the merchant certificate in the c:WINDOWS directory, then create a form and submit the specified data to the webpage designated by ICBC.

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