Learning With Errors (LWE) and Ring LWE

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The method describing LWE is defined here.

Learning With Errors (LWE) is a quantum robust method of cryptography. It is also used within homomorphic encryption. Initially we create a secret key value (s) and another value (e). Next we select a number of values (A[]) and calculate B[] = A[] x s + e. The values of A[] and B[] become our public key. If s is a single value, A and B are one dimensional matrices. If we select s to be a one-dimensional matrix, A will be a two-dimensional matrix, and B will be a one-dimensional matrix.

Outline

Learning with errors is a method defined by Oded Regev in 2005 [here] and is known as LWE (Learning With Errors). It involves the difficulty of finding the values which solve:

B=A×s+e

where you know A and B. The value of s becomes the secret values (or the secret key), and A and B can become the public key.

Slides: [here]

Basics for LWE

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Prof Bill Buchanan OBE FRSE
ASecuritySite: When Bob Met Alice

Professor of Cryptography. Serial innovator. Believer in fairness, justice & freedom. Based in Edinburgh. Old World Breaker. New World Creator. Building trust.