Infineon Technologies Ag

Markus Rau

Stefan Heiss

Berndt Gammel

Thomas Poeppelmann

Stefan Hackenberg

Stephan Wassmann

A cryptographical apparatus for converting input bit sequences, whose overflow-free arithmetic addition results in a secret, into output bit sequences whose logic XORing results in the secret. The apparatus comprises a data interface for providing a first input bit sequence and a second input bit sequence and a processing circuit configured to a) gate the first input bit sequence and the second input bit sequence to obtain a logic result indicating overflow bit positions at which both the first input bit sequence and the second input bit sequence have a value of one; and to b) change the first and/or second input bit sequence at at least one overflow bit position. The processing circuit is configured to repeatedly perform steps a) and b) by using the respectively changed input bit sequences, until the logic result indicates no further overflow bit position and the output bit sequences are obtained.

Apparatus and method for converting input bit sequences

A method is provided for conducting an operation, the method including: determining a first result based on combining a first input with a first mask; determining a second result based on combining a second input with a second mask, the first mask and the second mask fulfilling a precondition; and conducting the operation based on the first result and the second result. A corresponding device is also provided.

Side-channel hardened operation

According to an embodiment, a data processing device is described comprising a deformer configured to deform a first data block in accordance with a first seed, a seed generator configured to generate a sequence of second seeds, wherein the sequence of second seeds comprises the first seed, a cryptographic processor configured to receive the deformed first data block and, for each second seed, to deform the deformed first data block in accordance with the second seed, to generate a sequence of second data blocks and to cryptographically process each second data block of the sequence of second data blocks to generate a sequence of processed data blocks and an extractor configured to extract a result of the cryptographic processing of the first data block from the sequence of processed data blocks.

Data processing device and method for cryptographic processing of data

According to one embodiment, a method for protecting data is provided comprising receiving a plurality of data symbols, determining a sequence of checksum symbols wherein the checksum symbols are determined to be equal to the checksum symbols of the last iteration of an iterative checksum symbol generation process, wherein the determining of the checksum symbols includes at least one of randomly generating the initial values, randomly determining an order of the data symbols in which the contributions of the data symbols to the checksum symbols are incorporated into the checksum symbols and masking each data symbol and using the masked data symbols as data symbols for determining the checksum symbols and which includes storing at least some of the checksum values as checksum for the data symbols.

Method for protecting data and data processing device

A method for performing an operation based on at least two operands is proposed, in which steps of the operation are performed in time-randomized fashion. In addition, an apparatus, a computer program product and a computer-readable storage medium are accordingly specified.

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Gessertshausen, Germany

Markus Rau