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Have you ever wanted to know how your data in OneDrive for Business or SharePoint Online is stored and protected with the latest encryption technology?
When you store your data in OneDrive for Business or SharePoint Online, it’s safeguarded with the strongest encryption and detection technologies available.
At the disk encryption level, BitLocker is used to secure data and at the file encryption level, every file is secured with its own key that uses Advanced Encryption Standard (AES) with 256-bit keys and is Federal Information Processing Standard (FIPS) 140-2 compliant.
For additional information about how encryption works to protect your data, see the article titled, “Data Encryption for OneDrive for Business and SharePoint Online.”
Source: How data encryption works in OneDrive for Business and SharePoint Online