# Michel Douguet, Marseille FR

## Michel Douguet, Marseille FR

Patent application number | Description | Published |
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20080226064 | CHINESE REMAINDER THEOREM - BASED COMPUTATION METHOD FOR CRYPTOSYSTEMS - A computer hardware implemented cryptography method computes a modular exponentiation, M:=C | 09-18-2008 |

20090016523 | Masking and Additive Decomposition Techniques for Cryptographic Field Operations - Masking and additive decomposition techniques are used to mask secret material used in field operations (e.g., point multiplication operations) performed by cryptographic processes (e.g., elliptic curve cryptographic processes). The masking and additive decomposition techniques help thwart “side-channel” attacks (e.g., power and electromagnetic analysis attacks). | 01-15-2009 |

20090041229 | Elliptic Curve Point Transformations - In an elliptic curve cryptographic system, point coordinates in a first coordinate system are transformed into a second coordinate system. The transformed coordinates are processed by field operations, which have been modified for operating on the transformed point coordinates. In some implementations, the point coordinates are transformed using a linear transformation matrix having coefficients. The coefficients can be fixed, variable or random. In some implementations, the transformation matrix is invertible. | 02-12-2009 |

20090180609 | Modular Reduction Using a Special Form of the Modulus - A special form of a modulus and a modified Barrett reduction method are used to perform modular arithmetic in a cryptographic system. The modified Barrett reduction is a method of reducing a number modulo another number without the use of any division. By pre-computing static values used in the Barrett reduction method and by using a special form of the modulus, the calculation of reducing a number modulo another number can be reduced. This can result in a decrease in computation time, speeding up the overall cryptographic process. | 07-16-2009 |

20090180611 | REPRESENTATION CHANGE OF A POINT ON AN ELLIPTIC CURVE - An elliptic curve cryptographic system where point coordinates are transformed from a first coordinate system to a second coordinate system. The transformed coordinates are processed by field operations, which have been modified for operating on the transformed point coordinates. In some implementations, the point coordinates are transformed from an affine coordinate system to a projective coordinate system using a non-random value for the projective coordinate. In some implementations, the transformed projective representation of the point can be changed from a first representation of the point in projective coordinates to a second representation of the point in projective coordinates, where the projective coordinate used in the representation change is a random value. | 07-16-2009 |

20100023572 | RANDOMIZED MODULAR POLYNOMIAL REDUCTION METHOD AND HARDWARE THEREFOR - A cryptographically secure, computer hardware-implemented binary finite-field polynomial modular reduction method estimates and randomizes a polynomial quotient used for computation of a polynomial remainder. The randomizing error injected into the approximate polynomial quotient is limited to a few bits, e.g. less than half a word. The computed polynomial remainder is congruent with but a small random multiple of the residue, which can be found by a final strict binary field reduction by the modulus. In addition to a computational unit and operations sequencer, the computing hardware also includes a random or pseudo-random number generator for producing the random polynomial error. The modular reduction method thus resists hardware cryptoanalysis attacks, such as timing and power analysis attacks. | 01-28-2010 |

20100220863 | Key Recovery Mechanism for Cryptographic Systems - A cryptographic system can include a register containing a key and a processor coupled to the register. The processor can be operable for performing a first encrypting operation, where the encrypting operation includes computing a key schedule using the register as a workspace. At the end of the first encrypting operation, the key is recovered from the register for use in a second encrypting operation. | 09-02-2010 |

20110016167 | RANDOMIZED MODULAR POLYNOMIAL REDUCTION METHOD AND HARDWARE THEREFOR - A cryptographically secure, computer hardware-implemented binary finite-field polynomial modular reduction method estimates and randomizes a polynomial quotient used for computation of a polynomial remainder. The randomizing error injected into the approximate polynomial quotient is limited to a few bits, e.g. less than half a word. The computed polynomial remainder is congruent with but a small random multiple of the residue, which can be found by a final strict binary field reduction by the modulus. In addition to a computational unit and operations sequencer, the computing hardware also includes a random or pseudo-random number generator for producing the random polynomial error. The modular reduction method thus resists hardware cryptoanalysis attacks, such as timing and power analysis attacks. | 01-20-2011 |

20110213819 | MODULAR MULTIPLICATION METHOD WITH PRECOMPUTATION USING ONE KNOWN OPERAND - A modular multiplication method implemented in an electronic digital processing system takes advantage of the case where one of the operands W is known in advance or used multiple times with different second operands V to speed calculation. The operands V and W and the modulus M may be integers or polynomials over a variable X. A possible choice for the type of polynomials can be polynomials of the binary finite field GF(2 | 09-01-2011 |

20130080790 | Encrypted Memory Access - Various systems and methods for encrypting data are disclosed. In one aspect, the method includes receiving a memory address and a value to be written in the memory address. The method also includes encrypting the value using the memory address as an initial value for an encryption process. The method also includes storing the encrypted value in the memory address. | 03-28-2013 |