Root Certificate Rules for the Transport Department Interconnect Code

Introduction: The article updates guidance to better serve the Transport Department’s interconnect code, noting that the Zhongjin root certificate can be self‑generated.

Code Adjustments

Ensure the central public‑key index is unique on the device side, because the device uses this index to locate the certificate and public key.

Provide the root public key to the device: keep the generated private key, open the key folder, and give the publicKey.pem file to the device for root‑certificate validation.

Modify the generation parameters— centralCAPublicKeyIndex, certificateExpired, issuer public key gy, and storage address —then run the main method to create the root certificate and key pair. Concatenate the central public‑key string according to the existing rule, store the root certificate, and supply its public key to the device.

Reference

The implementation follows the “Transport Department QR Code Technical Specification JTT1179‑2018”.

Logical Flow

As shown in the diagram, the device first validates the issuing‑institution’s public‑key certificate against the central public key from the certificate management center. After that, the issuing‑institution’s public key verifies the signature of the issuing‑institution’s authorization. Then the payment account’s private‑key signature is checked with its public key. Only when all signatures are valid does the system validate the actual QR‑code data.