Cryptography Research, Inc.

Rambus Inc.

Elke De Mulder

Elena Trichina

Pankaj Rohatgi

Jean-Michel Cioranesco

Guilherme Ozari De Almeida

Matthew Pond Baker

Craig Edward Hampel

Michael Hutter

Winthrop Wu

Sami James Saab

Jeremy Cooper

Roberto Rivoir

Samatha Gummalla

Rodrigo Portella Do Canto

Samantha Gummalla

Systems and methods for protecting from external monitoring attacks cryptographic data processing operations involving computation of a universal polynomial hash function, such as GHASH function. An example method may comprise: receiving an input data block, an iteration result value, and a mask value; performing a non-linear operation to produce a masked result value, wherein a first operand of the non-linear operation is represented by a combination of the iteration result value and the input data block, and the second operand of the non-linear operation is represented by a secret hash value, and wherein one of the first operand or the second operand is masked using a mask value; determining, based on the mask value, a mask correction value; and producing a new iteration result value by applying the mask correction value to the masked result value.

Protecting polynomial hash functions from external monitoring attacks

Systems and methods for protecting from external monitoring attacks cryptographic data processing operations involving universal polynomial hash functions computation. An example method may comprise: receiving an input data block and an iteration result value; performing a first field multiplication operation to produce a new iteration result value, by iteratively processing, starting from a first bit position, bits of a combination of the input data block and the iteration result value, wherein the first bit position is represented by one of: a least-significant bit and a most-significant bit; performing a second field multiplication operation to produce a new mask correction value, by iteratively processing operand bits starting from a second bit position, wherein the second bit position is represented by one of: a least-significant bit and a most-significant bit, and wherein the second bit position is different from the first bit position; applying the new mask correction value to the new iteration result value; and producing, based on the new iteration result value, a value of a cryptographic hash function to be utilized by at least one of: an authenticated encryption operation or an authenticated decryption operation.

Protecting parallel multiplication operations from external monitoring attacks

Aspects of the present disclosure calculate masked data shares dynamically inside the CPU boundary, and use a plurality of memory channels to write the masked data shares to an external memory location and/or to read the data shares from that external memory location. Each dynamically generated mask value is uniquely associated with a corresponding memory channel during writing data to the external memory. The modified masked data is unmasked or remasked during a subsequent read operation.

Side-channel-attack-resistant memory access on embedded central processing units

Systems and methods for protecting block cipher computation operations, from external monitoring attacks. An example apparatus for implementing a block cipher may comprise: a first register configured to store a first pre-computed mask value represented by a combination of a first random value and a second random value; a second register configured to store an output mask value, wherein the output mask value is an inverse permutation function of the first random value; a third register configured to store a second pre-computed mask value represented by a combination the first pre-computed mask value and a permutation function of the output mask value; a fourth register configured to store an input mask value, wherein the input mask value is a combination of an expansion function of the first random value and a key mask value; a non-linear transformation circuit configured to apply the expansion function to a masked round state, perform a non-linear transformation of a combination of a masked key with an output of the expansion function, and apply the permutation function to the output of the non-linear transformation, wherein the non-linear transformation is defined using the input mask value stored in the fourth register and the output mask value stored in the second register; and two round feedback circuits configured to swap the masked round state produced by the non-linear transformation and combine the masked round state with the first pre-computed mask value stored in the first register and the second pre-computed mask value stored in the third register.

Protecting block cipher computation operations from external monitoring attacks

Embodiments herein facilitate resisting side channel attacks through various implementations and combinations of implementations. In embodiments, this is accomplished by preventing sensitive data from consecutively following other data through potentially vulnerable resources which otherwise may cause data to leak. Where such vulnerabilities to attacks are known, suspected, or as a proactive precaution, a cleaner can be used to inhibit the sensitive data from passing through the vulnerable areas consecutively and thus inhibit the leakage. Embodiments also envision utilizing certain types of circuits to assist in preventing leakage. By using such circuits one can reduce or even potentially eliminate the requirement for cleaners as mentioned previously.

Enhancements to improve side channel resistance

An indication of a mode of operation to be performed with a block cipher may be received. Logic associated with the block cipher may be configured based on the indicated mode of operation to be performed with the block cipher. Furthermore, an input data and a mask data may be received. The input data may be combined with the mask data to generate a masked input data based on the configured logic. The masked input data may be provided to the block cipher based on the configured logic and an output data may be generated with the block cipher based on the provided masked input data.

Programmable block cipher with masked inputs

Systems and methods for performing cryptographic data processing operations employing non-linear share encoding for protecting from external monitoring attacks. An example method includes: receiving a plurality of shares representing a secret value employed in a cryptographic operation, such that the plurality of shares includes a first share represented by an un-encoded form and a second share represented by an encoded form; producing a transformed form of the second share; and performing the cryptographic operation using the transformed form of the second share.

Cryptographic operations employing non-linear share encoding for protecting from external monitoring attacks

A side-channel attack resistant circuit topology for performing logic functions. This topology includes combinatorial logic to perform the at least one logic function. A logic input selector alternately supplies, in response to a first timing reference signal, an input to the combinatorial logic with noise generating input values and valid input values. A first latch input selector alternately supplies, in response to the first timing reference signal, a first memory element input with noise generating input values and valid logic output values. The valid logic output values are received from the combinatorial logic. A first memory element latches the valid logic output values in response to a second timing reference signal.

Low overhead random pre-charge countermeasure for side-channel attacks

Share values for use in a cryptographic operation may be received and the cryptographic operation may be performed based on the share values. A pseudorandom number that is to be used by the cryptographic operation may be identified and the pseudorandom number may be generated based on a portion of the share values that are used in the cryptographic operation. The cryptographic operation may then be performed based on the generated pseudorandom number.

Growing community of inventors

Kirkland, WA, United States of America

Elke De Mulder