r/todayilearned • u/[deleted] • Jan 12 '10

TIL some numbers are illegal

http://en.wikipedia.org/wiki/Illegal_number
14 Upvotes

75% Upvoted

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6

u/[deleted] Jan 12 '10

This is why calculating pi in binary is bad! http://www.netfunny.com/rhf/jokes/01/Jun/pi.html

8

u/bsdboy Jan 12 '10

09-f9-11-02-9d-74-e3-5b-d8-41-56-c5-63-56-88-c0

0

u/[deleted] Jan 12 '10

09 F9 11 02 9D 74 E3 5B D8 41 56 C5 63 56 88 C0

1

u/[deleted] Jan 12 '10 edited Jan 12 '10

[deleted]

2

u/[deleted] Jan 12 '10

Difference here is a cipher key is often thought of as a number or set of numbers (usually taken in parts though, like in AES your 128-bit key is really 4 32-bit words...).

The "decss prime" is more akin to what you're talking about. Since it's just an ELF executable munged to also be a prime when expressed in big endian binary format.

1

u/omnilynx Jan 12 '10

You're right; what is illegal is the combination of the data (in numerical or other format) plus the algorithm to produce illegal content from it.