I'm confused as to how they've done this. The original message, sure, you can brute force the digits and hope you get a collision, and try a new, plausible preamble if not. But I don't see how they've found this collision without it looking like anything is brute forced.
Is it using substitute Unicode characters or something?
Is it using substitute Unicode characters or something?
E: no, just hand typed it and got the same...