US 10,853,502 B1 · Systems and methods for reducing computational difficulty of cryptographic operations

Abstract

Computing equipment may perform format-preserving encryption and decryption by partitioning an input string into first and second portions. The computing equipment may combine the first portion with the second portion after the second portion has been passed through a pseudorandom function using a format-preserving combination operation that requires inputs having a similar domain size. A data size adjustment engine may adjust the domain size of the output of the pseudorandom function to be similar to the domain size of the first string. In order to mitigate undesirable data overflows, the output of the pseudorandom function may be partitioned into a number of computationally simpler terms each having a modulo factor and a pre-computed constant value. The computing equipment may pre-compute the constant values in advance, thereby reducing the computational complexity required for performing the size adjustment operations without generating undesirable data overflows.

Claims20

Dependent claims

A method of mitigating data overflows while performing format-preserving cryptographic operations using computing equipment having storage circuitry, a cryptographic engine, and a data size adjustment engine, the method comprising:

with the computing equipment, storing a set of pre-computed constant values on the storage circuitry including a first pre-computed constant value and a second pre-computed constant value;
with the data size adjustment engine, obtaining an extracted data string from the cryptographic engine and partitioning the extracted data string into a plurality of string portions including a first portion and a second portion;
with the data size adjustment engine, retrieving the stored set of pre-computed constant values from the storage circuitry;
and
with the data size adjustment engine, combining the first pre-computed constant value with the first portion to generate a first size-adjusted output value and combining the second pre-computed constant value with the second portion to generate a second size-adjusted value, wherein the first size-adjusted output value and the second-size-adjusted value are generated based on a given size.

2 more elements

A method of performing encryption operations using computing equipment having an encryption engine, a data extraction engine, and an output size adjustment engine, the method comprising:

with the computing equipment, partitioning an input plaintext string into a first plaintext portion and a second plaintext portion, wherein the first plaintext portion has a given domain size;
with the output size adjustment engine, generating a size-adjusted output value based on the given domain size by performing size adjustment operations on an extracted value, wherein the extracted value is generated by the encryption engine and the data extraction engine based on encrypting the second plaintext portion;
and
with the computing equipment, performing format-preserving combination operations on the size-adjusted output value and the first plaintext portion to generate a ciphertext string, wherein performing the size adjustment operations comprises:
mitigating data overflow while performing the size adjustment operations by partitioning at least some of the extracted value into a linear combination of terms, wherein each term of the linear combination of terms includes a modulo factor multiplied by a corresponding pre-computed constant value.

2 more elements

Dependencies are inferred from the claim text.

Systems and methods for reducing computational difficulty of cryptographic operations

Life of this patent

Systems and methods for reducing computational difficulty of cryptographic operations

Life of this patent

Abstract

Claims20