Protection of a cryptographic operation
AssigneeSTMicroelectronics (Rousset) SAS
InventorGuilhem ASSAEL
Life of this patent
Estimating the term…
Abstract
The present disclosure relates to a cryptographic method comprising: multiplying a point belonging to a mathematical set with a group structure by a scalar by performing: the division of a scalar into a plurality of groups formed of a same number w of digits, w being greater than or equal to 2; and the execution, by a cryptographic circuit and for each group of digits, of a sequence of operations on point, the sequence of operations being identical for each group of digits, at least one of the operations executed for each of the groups of digits being a dummy operation.
Claims25
A method, comprising:
- multiplying, using cryptographic circuitry, a point, belonging to a mathematical set with a group structure, by a scalar;
- and
- protecting, using the cryptographic circuitry, the scalar during the multiplying, the multiplying and protecting including:
- dividing the scalar into a plurality of groups formed of a same number w of digits, w being greater than or equal to 2;
- and
- executing, for each group of digits, of a sequence of operations on the point, the sequence of operations having a same sequence for each group of digits, at least one of the operations executed for each of the groups of digits being a dummy operation.
A device, comprising:
- a memory;
- and
- cryptographic circuitry coupled to the memory, wherein the cryptographic circuitry, in operation, multiplies a point by a scalar, the point belonging to a mathematical set with a group structure, and protects the scalar during the multiplying, the multiplying and protecting including:
- dividing the scalar into a plurality of groups formed of a same number w of digits, w being greater than or equal to 2;
- and
- executing, for each group of digits, of a sequence of operations on the point, the sequence of operations having a same sequence for each group of digits, at least one of the operations executed for each of the groups of digits being a dummy operation.
A system, comprising:
- a host processor;
- and
- a cryptographic coprocessor coupled to the host processor, wherein the cryptographic coprocessor, in operation, multiplies a point by a scalar, the point belonging to a mathematical set with a group structure, and protects the scalar during the multiplying, the multiplying and protecting including:
- dividing the scalar into a plurality of groups formed of a same number w of digits, w being greater than or equal to 2;
- and
- executing, for each group of digits, of a sequence of operations on the point, the sequence of operations having a same sequence for each group of digits, at least one of the operations executed for each of the groups of digits being a dummy operation.
A non-transitory computer-readable medium having contents which configure cryptographic circuitry to multiply a point by a scalar, the point belonging to a mathematical set with a group structure, and protect the scalar during the multiplying, the multiplying and protecting including:
- dividing the scalar into a plurality of groups formed of a same number w of digits, w being greater than or equal to 2;
- and
- executing, for each group of digits, of a sequence of operations on the point, the sequence of operations having a same sequence for each group of digits, at least one of the operations executed for each of the groups of digits being a dummy operation.
Dependencies are inferred from the claim text.