Trying to install magento 2 on localhost. I am getting this message

Invalid credentials for 'repo.magento.com/packages.json', aborting.

Initially, I had created a secure key by navigating to magentocommerce.com/magento-connect/customerdata/secureKeys/list/ url.

I tried composer create-project --repository-url=https://repo.magento.com/ magento/project-community-edition <installation directory name> command and entered the username as public key and password as private key. I was then prompted whether I need to save it? And I selected the option "Y".

But by some mistake the secure key got deleted.

Now, when I am trying to create a new project, its giving me

Invalid credentials for 'https://repo.magento.com/packages.json', aborting.

I want to update my auth.json file . But I'm unable to get the command. Can you please help me for the same?