Composably secure device-independent encryption with certified deletion

Composably secure device-independent encryption with certified deletion

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We study the task of encryption with certified deletion (ECD) introduced by Broadbent and Islam (2020), but in a device-independent setting: we show that it is possible to achieve this task even when the honest parties do icon track bar f250 not trust their quantum devices.Moreover, we define security for the ECD task in a composable manner and show that our ECD protocol satisfies conditions that lead to composable security.Our protocol is based on device-independent quantum key distribution (DIQKD), and in particular the parallel DIQKD protocol based on the magic square non-local game, given by Jain, Miller and Shi (2020).

To achieve certified deletion, we use a property of the magic square game observed by Fu and Miller (2018), namely that a two-round variant of the game can be used to certify deletion of a single random bit.In order to achieve certified deletion security for arbitrarily long messages from this property, we prove a parallel repetition theorem for two-round ice blue graphic tee non-local games, which may be of independent interest.