Personal secrets
Belong to an individual. Examples include the usernames and passwords for websites you visit, your SSH keys, and your Pretty Good Privacy (PGP) keys.
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Customer secrets
Belong to your customers. Note that if you run software for other employees of your company—e.g., you manage your company’s internal Active Directory server—then those other employees are your customers. Examples include the usernames and passwords that your customers use to log into your product, personally identifiable info (PII) for your customers, and personal health information (PHI) for your customers.
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Infrastructure secrets
Belong to your infrastructure. Examples include database passwords, API keys, and TLS certificates.
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