5 ms·
The process is fairly simple. 1. Take illegal number 2. GZip it, or at least store it in a format that discards trailing null bytes. 3. Multiply it by a powe
by KMnO4 6y ago
The process is fairly simple.
1. Take illegal number
2. GZip it, or at least store it in a format that discards trailing null bytes.
3. Multiply it by a power of 256
Every power of 256 adds a zero to the end, in the same way that multiplying 5x10=50, 5x100=500, etc.
4. Add a an integer and check primality; repeat.
So if the illegal number was 12345 your could have an illegal prime 1234500000071 represented by (12345x256^8+71).
The only reason you’d want to do this is because people actually share seemingly random prime numbers online. There’s no legal reason to share the DeCSS encryption code, but a prime number with a length of 2000 is “interesting” enough to avoid legal issue.
- Y_Y 6y agoDo you imagine a judge would just say "well fuck it, he published the illegal number, but appended some shit to the end, so maybe it's just an astronomical coincidence"?
- bzbarsky 6y agoThe point is, if the resulting prime number is large enough to be in the very public "list of N largest known primes", how do you keep it out of that list, exactly? But also, as pointed out elsewhere in this thread, your hypothetical is more or less what happened with the DeCSS primes Phil Carmody published. Except it never even got to a judge.
- bostonpete 6y agoJust to be clear -- b/c I got a bit confused reading this -- this example seems to assume "12345" and "71" are base-256 numbers and "256" is base-10.
- Zircom 6y agoOnce you compress the number it becomes stored in base-256 due to how the gzip file format works was my understanding
- bostonpete 6y agoSure, the benefit of base-256 is that a 0 maps to a byte with all 0's in the binary representation of the integer -- it's nothing specific to gzip. But on its face, 12345x256^8+71 = 1234500000071 is just wrong and only works once you realize that it's combining integers from different number systems.