Paytm PG uses the checksum signature to ensure integrity and data-authenticity verification before sending data to the API. Paytm PG validates the authenticity of the credentials when they are received.
Note: Checksum is a string of numbers and letters that act as a fingerprint for API requests and responses. It is used to authenticate that the requests and responses are coming from a trusted source and that the information is not getting tampered with. It ensures that the transported content is the same as it was when it was sent.
Paytm uses the SHA256 hashing and AES128 encryption algorithms to calculate the checksum and ensure the safety of transaction data. The checksum is calculated on all request parameters posted to the API and requires data to be posted to the Paytm server in the NVP (Name-Value Pairs) format.