US Patent 10423804 Cryptographic separation of users

Techniques are disclosed relating to securely storing data in a computing device. In one embodiment, a computing device includes a secure circuit configured to maintain key bags for a plurality of users, each associated with a respective one of the plurality of users and including a first set of keys usable to decrypt a second set of encrypted keys for decrypting data associated with the respective user. The secure circuit is configured to receive an indication that an encrypted file of a first of the plurality of users is to be accessed and use a key in a key bag associated with the first user to decrypt an encrypted key of the second set of encrypted keys. The secure circuit is further configured to convey the decrypted key to a memory controller configured to decrypt the encrypted file upon retrieval from a memory.