CIN stands for Challan Identification Number. It is a 17-digit number that is 14-digit CPIN plus 3-digit Bank Code. CIN is generated by the authorized banks/ Reserve Bank of India (RBI) when payment is actually received by such authorized banks or RBI and credited in the relevant government account held with them. It is an indication that the payment has been realized and credited to the appropriate government account. CIN is communicated by the authorized bank to taxpayer as well as to GSTN.