# Gebotys

## Catherine Helen Gebotys, Waterloo CA

Patent application number | Description | Published |
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20110033043 | TABLE MASKING FOR RESISTANCE TO POWER ANALYSIS ATTACKS - Tables are defined to permit output masking for table look-ups to be carried out to resist power analysis attacks on cryptographic operations. A set of individually defined random values is used to mask each entry in a substitution table, defining a masked substitution table. A mask table is also defined such that the values of each entry, masked with the corresponding random value, is the value of a fixed mask. The masked substitution tables and the mask tables may be used in cryptographic operations to permit the output of table look-ups to be masked, without directly using the fixed mask value in the computations of the cryptographic operations. | 02-10-2011 |

20110064225 | SECURITY COUNTERMEASURE FOR POWER ANALYSIS ATTACKS - A countermeasure for differential power analysis attacks on computing devices. The countermeasure includes the definition of a set of split mask values. The split mask values are applied to a key value used in conjunction with a masked table defined with reference to a table mask value. The set of n split mask values are defined by randomly generating n−1 split mask values and defining an nth split mask value by exclusive or'ing the table mask value with the n−1 randomly generated split mask values. | 03-17-2011 |

## Catherine Helen Gebotys, Baden CA

Patent application number | Description | Published |
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20110261958 | TABLE SPLITTING FOR CRYPTOGRAPHIC PROCESSES - For a defined cryptographic process including an original substitution table, split masked substitution tables are provided to resist cryptographic attacks. The split masked substitution tables are defined with reference to a set of random value data words and a mask value. An entry in the split masked substitution tables is defined by selecting bits from the corresponding entry in the original masked substitution table, as masked by the corresponding one of the set of random value data words and by selecting bits from the corresponding one of the set of random value data words as masked by the mask value. The split masked substitution tables are usable in a modified cryptographic process based on the defined cryptographic process to permit a masked output to be generated. The split masked substitution tables are refreshed by each entry in the tables being refreshed upon access during execution of the modified cryptographic process. | 10-27-2011 |

## Catherine Helen Gebotys, Waterloor CA

Patent application number | Description | Published |
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20130016834 | SECURITY COUNTERMEASURES FOR POWER ANALYSIS ATTACKS - A countermeasure for differential power analysis attacks on computing devices. The countermeasure includes the definition of a set of split mask values. The split mask values are applied to a key value used in conjunction with a masked table defined with reference to a table mask value. The set of n split mask values are defined by randomly generating n−1 split mask values and defining an nth split mask value by exclusive or'ing the table mask value with the n−1 randomly generated split mask values. | 01-17-2013 |