A system protects personally identifiable information (PII) by implementing an unconventional key management scheme. In this scheme, the system uses a set of keys rather than an individual key for encrypting PII. Different portions of the PII are encrypted using different keys from the set of keys. In this manner, even if a malicious user were to access a key, that key would not give the malicious user the ability to decrypt all of the PII. Additionally, the system generates a new set of keys periodically (e.g., once a month). The system also deletes sets of keys that are too old (e.g., six months old). As a result, even if a malicious user were to access a key, the usefulness of that key would be time limited.