Encryption engine having randomized round scheduling to prevent side channel attacks

2:

• The artificial reality system of claim 1, wherein to select the permutation of the inputs for a respective round of the plurality of rounds, the decryption engine is configured to:
• generate a random number for the respective round;
• and
• select the permutation of the inputs based on the random number being associated with the selected permutation of the inputs.

9:

• An apparatus for data decryption, the apparatus comprising:
• an interface configured to receive an encrypted block of data;
• and
• a decryption engine in communication with the interface, the decryption engine being configured to:
• for each round of a plurality of rounds for decrypting the block of encrypted data, select a permutation of inputs to the decryption engine from a plurality of permutations of the inputs, wherein the inputs include encrypted data segments of the block of encrypted data and an inverse cipher key segment, and wherein the selected permutation of the inputs is different for at least two rounds of the plurality of rounds;
• and
• iteratively compute a portion of a decrypted block of data across the plurality of rounds based on the respective selected permutation of the inputs for each round to form a decrypted data segment.

10:

• The apparatus of claim 9, wherein to select the permutation of the inputs for a respective round of the plurality of rounds, the decryption engine is configured to:
• generate a random number for the respective round;
• and
• select the permutation of the inputs based on the random number being associated with the selected permutation of the inputs.

18:

• A method of decrypting encrypted data, the method comprising:
• selecting, for each round of a plurality of rounds for decrypting a block of encrypted data, by a decryption engine, a permutation of inputs to the decryption engine from a plurality of permutations of the inputs, wherein the inputs include encrypted data segments of the block of encrypted data and an inverse cipher key segment, and wherein the selected permutation of the inputs is different for at least two rounds of the plurality of rounds;
• and
• iteratively computing, by the decryption engine, a portion of a decrypted block of data across the plurality of rounds based on the respective selected permutation of the inputs for each round to form a decrypted data segment.

19:

• The method of claim 18, wherein selecting the permutation of the inputs for a respective round of the plurality of rounds comprises:
• generating, by the decryption engine, a random number for the respective round;
• and
• selecting, by the decryption engine, the permutation of the inputs based on the random number being associated with the selected permutation of the inputs.

21:

• An artificial reality system comprising:
• an encryption engine configured to:
• for each round of a plurality of rounds for encrypting a block of input data, select a permutation of inputs to the encryption engine from a plurality of permutations of the inputs, wherein the inputs include data segments of the block of input data and a cipher key segment, and wherein the selected permutation of the inputs is different for at least two rounds of the plurality of rounds;
• and
• iteratively compute an encrypted block of data across the plurality of rounds based on the respective selected permutation of the inputs for each round to form an encrypted data segment;
• and
• a head-mounted display (HMID) configured to output the encrypted data segment.