Cloud Identity and Access Management (IAM)

A Service Account is an account used to identify services (non-humans) to
Google. A Service Account has a list of Service Account Keys, which can be used
to authenticate to Google.

A Service Account Key is a public/private keypair generated by Google. Google
retains the public key, while the customer is given the private key. The private
key can be used to sign JWTs and authenticate Service Accounts to Google.

WWW: https://github.com/googleapis/googleapis/tree/master/google/iam