The first method: double-click the certificate file and enter the protection password of the certificate correctly according to the page prompts (this password was set when you exported the certificate), and the certificate will be reinstalled in your computer's browser.
The second method: If you are using IE browser, you can open the browser, click the Internet option under the Tools menu, then select the certificate under the Content menu, click the Import button, and import the certificate according to the page prompts. During this process, when you correctly enter the protection password of the certificate (this is the password you set when exporting the certificate), the certificate will be reinstalled on your computer.
Certificates can only be saved in pfx file format, and certificates in cer format cannot be imported and used.
If your online banking certificate can no longer be used, you can only cancel online banking, re-register and sign a contract, and then download a new certificate again. However, CCB stipulates that newly signed online banking customers must purchase new USBKEY or dynamic password cards together. Therefore, it is suggested that there is no need to cancel the online banking and re-sign. You only need to bring your valid ID card, online banking signing account and the mobile phone or PHS bound at the time of online banking signing directly to any local CCB outlet where you open an account, and the counter staff will handle the binding procedures for you (the staff will bind the new USBKEY with the corresponding online banking customer number). After the USBKEY is successfully bound, if the certificate has been downloaded before, the original soft certificate will be invalid. You must log in to online banking within seven days to download the certificate again, and you will be prompted to download the new certificate to the new USBKEY. After success, you can log on to online banking to conduct transactions.