The merchant key provided by PayU. It is a unique identifier for the merchant account.

The API command name. For refund or canceling transactions, the value should be 'cancel_refund_transaction'.

The PayU Transaction ID (mihpayid) that you receive in the response of a successful payment.

The Token ID (unique token generated by the merchant). This token should be unique for every refund request and helps track the request. Maximum 23 characters.

The amount to be refunded. For full refund, this should equal the original transaction amount. For partial refund, this should be less than the original transaction amount.

Refund split information for split transactions, provided in JSON format. Contains information on amounts to split between sub-merchants or child merchants.

A hash value for security validation. It is calculated using the sha512 algorithm with the format: sha512(key|command|var1|salt).