Paper 2020/074

Rolling up sleeves when subversion's in a field?

Daniel R. L. Brown

Abstract

A nothing-up-my-sleeve number is a cryptographic constant, such as a field size in elliptic curve cryptography, with qualities to assure users against subversion of the number by the system designer. A number with low Kolmogorov descriptional complexity resists being subverted to the extent that the speculated subversion would leave a trace that cannot be hidden within the short description. The roll programming language, a version of Godel's 1930s definition of computability, can somewhat objectively quantify low descriptional complexity, a nothing-up-my-sleeve quality, of a number. For example, curves NIST-P-256, Curve25519, and NIST-P-521 have fields sizes with roll programs of 112, 84, and 63 words (respectively).

Note: Latest versions shortens programs for field sizes of NIST curves P-521 and K-283.