This will be the page for improvement!
Go through the first three chapters of the “Birth of cryptography” upto and including “Mechanising secrecy”
Crack the crypted text of you fellow student using the Vigen`re cipher tool Go through the previous two steps again, this time using a cipher of your own choosing
I gave Berry two cipher to crack. one is Vigen`re, the other one is ROT +2, forgot to put ROT on the log. Please kindly find below the ROT
icw-umpb-sqcb-gl-tgeclcpc-gq-emmbbyw-rfgq-ayl-kyic-rfgleq-ksaf-cyqgcp-dmp-wms
clear text
key-word-used-in-vigenere-is-goodday-this-can-make-things-much-easier-for-you
Berry complained that the keyword I used in viginere is too short so I mailed him a new cipher with new key. That's why the keywords don't match each other.
Enigma key space calculation
We have to take into account several variables.
- number of used rotors/number of total rotors (nr=rotor used/n=total rotor)
- original position of each used rotor (26^nr)
- kickover point of the number of used rotor - 1 (26^(nr-1))
- wiring on plugboard (m=number of wires, n=26 which is the number of sockets. The number of ways of choosing m pairs out of n objects is
(n!/((n-2m)! m! 2m))
The amount of keys is calculated like this:
| var | Description | Possibilities |
|---|---|---|
| a= | 3 rotors used out of 4 rotors in total (it is actually 4*3*2, but the result is the same): | 4! |
| b= | 3 rotors with 26 starting positions: | (26)3 |
| c= | Kickover positions of 2 rotors: | 262 |
| d= | 10 plugs for 26 holes: | 26!/((26-2*10)! * 10! * 2 * 10) |
| Total possibilities: | a*b*c*d | |
