Cryptography Research, Inc.

Systems and methods for efficient computation of stream ciphers. An example system for implementing a stream cipher, may comprise: a sub-round computation circuit of a first type configured to perform a subset of transformations of a cipher computation round on a round input state, each transformation of the subset of transformations including at least one of: a bitwise addition operation, a bitwise exclusive disjunction operation, or a bitwise rotation operation. The sub-round computation circuit of the first type may comprise: one or more of sub-round computation circuits of a second type, wherein each sub-round computation circuit of the second type is configured to perform the subset of transformations of the cipher computation round on a respective part of the round input state.

Aspects of the present disclosure involve a cryptographic processor that includes four or more multiplication circuits, two or more addition circuits, and two or more memory circuits. The cryptographic engine is configured to perform a variety of operations, including modular multiplication, modular inversion, matrix multiplication, Montgomery multiplication, computations of Jacobi symbols, and the like. The cryptographic engine support streaming computations where at least some of the multiplication circuits operate on multipliers and/or multiplicands that are also used during other cycles of computations.

Aspects of the present disclosure involve a method, a system and a computer readable memory to optimize performance of cryptographic operations by avoiding computations of inverse values during decryption of encrypted messages.

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.

Aspects and implementations are directed to systems and techniques for protecting cryptographic operations against side-channel attacks by masking a ciphertext data using one or more masks randomly sampled from a null space associated with a tensor representation of a secret data and generating a plaintext data using the masked ciphertext data.

Aspects of the present disclosure involve a method to perform a cryptographic operation using a plurality of iterations, each of the plurality of iterations comprising: loading a first number corresponding to a difference between a first component of a first input working point on an elliptic curve and a first component of a second input working point on the elliptic curve, loading a second number corresponding to a difference between the first component of the first input working point and a first component of a third input working point on the elliptic curve, and determining a third number corresponding to a difference between a first component of a first output working point on the elliptic curve and the first component of the second input working point, wherein determining the third number comprises squaring a product of the first number and a first function of the second number.

Aspects of the present disclosure involve a cryptographic processor that includes a systolic array having a plurality of processing lanes (PLs), each PL including a systolic sub-array of two or more processing elements (PEs), each PE being configured to multiply two numbers to obtain and store a multiplication product. The cryptographic processor is configured to efficiently perform a variety of operations, including multiplication of large numbers, modular reduction, Montgomery reduction, and the like.

An input data may be received. A portion of a cryptographic operation may be performed with the received input data at a first function component. During the performance of the cryptographic operation at the first function component, a pre-charge operation may be performed at a second function component. Furthermore, the second function component may be used to perform another portion of the cryptographic operation with a result of the portion of the cryptographic operation performed at the first function component.

Aspects of the present disclosure describe a method and a system to support execution of the method to perform a cryptographic operation involving identifying an N-word number, X=XN−1 . . . X 1 X o , to be squared, performing a first loop comprising M first loop iterations, wherein M is a largest integer not exceeding (N+1)/2, each of the M first loop iterations comprising a second loop that comprises a plurality of second loop iterations, wherein an iteration m of the second loop that is within an iteration j of the first loop comprises computing a product X a *X b of a word X a and a word X b , wherein a+b=2j+m, j≥0 and m≥0, and wherein all second loops have an equal number of second loop iterations.

A value corresponding to an input for a cryptographic operation may be received. The value may be masked by multiplying the value with a first number modulo a prime number. The cryptographic operation may subsequently be performed on the masked value.