Data encryption for data transfers between semiconductor dies using a keystream generator

A semiconductor die comprising:

• an input interface configured to receive encrypted data from at least one other semiconductor die via a physical interface;
• a keystream generator configured to generate, based on a key and an initial value, a keystream associated with the encrypted data;
• and
• decryption circuitry coupled to the keystream generator and configured to:
• receive, from the at least one other semiconductor die via the physical interface, a command as a start command indicating to initiate decryption;
• output decrypted data based on the encrypted data, the keystream, and the command;
• and
• receive, from the at least one other semiconductor die via the physical interface, the command as a stop command indicating to stop the decryption.

A method comprising:

• generating, at a first semiconductor die, a command to a second semiconductor die to initiate decryption;
• outputting, to a physical interface with the second semiconductor die, the command as a start command indicating that the second semiconductor die is to initiate the decryption;
• receiving data to be transferred to the second semiconductor die;
• generating, based on a key and an initial value, a keystream associated with the data;
• generating encrypted data based on the data and the keystream;
• outputting the encrypted data to the physical interface with the second semiconductor die;
• and
• outputting, to the physical interface, the command as a stop command indicating that the second semiconductor die is to stop the decryption.