Password-Controlled Encryption with Accountable Break-Glass Access

Abstract

We propose the notion of password-controlled encryption, a two-factor scheme involving a user-chosen password and the master public/secret key pair. The data owner obtains a secret key generated from a password and the master secret key of a key generation center (KGC) after authentication, and shares this password with encryptors and an emergency contact. In normal circumstances, the data owners can enforce access control by themselves. In emergency when the data owner is unavailable, any one with the same password can request for the decryption key from a KGC, without letting the KGC to know the password. At the same time, the KGC is held accountable if the key generation process is abused. Password-controlled encryption is especially applicable for protecting electronic medical record, which provides confidentiality with break-glass access, without relying on a key-escrow server or trusted hardware.