Browsers Do Math Differently on Every OS; Anti-Bot Systems Read the Bits

Transcendental functions are incredibly difficult to compute, they’re necessarily approximations. In “accurate” implementations they’re polynomial approximations where the exact polynomials produce different degrees of correctness in different places. The polynomial basis of the approximation is only accurate within a certain distance from zero.

You might think you can deal with that by reduction mod Pi or some such but pi is an approximation as well so that goes really wrong (x87’s transcendental functions did this and the correctness problems that caused are well documented to the extent that the hardware implementations are ignored and software implementations are used instead).

So the end result is that it is very difficult to actually produce identical results without identical implementations.

The part that garnered my interest was the bit about how the trig functions were fingerprint-able. That was surprising to me and was why I shared.

I was surprised to catch a "spam" flag for that.