A third hint for Challenge 10B
The Empty Vault › Forums › Bureau of Security and Signals Intelligence Forum › The official Challenge 10 tips and hints thread › A third hint for Challenge 10B
19th December 2022 at 9:00 am
#87584
Harry
Keymaster
A third hint for Challenge 10B
Too lazy to compute the factorisation yourself? I shouldn’t encourage that, but it is Christmas. There are 3250 characters in the text and 3250=2*5^3*13, so any transposition cipher is likely to be working with blocks of 1, 2, 5, 10, 13, 25, 26, 50, 65, 125, 130, 250, 325, 650, 1625, or 3250 letters. You have to hope that it is not 1625 or 3250 unless there is some obvious pattern, but in this case there is not!