1. LORENZ, COLOSSUS.ccawa

4. “Message” XOR <key> = <cryptotext>.

5. <cryptotext> XOR <key> = “Message”.

9. Message HQIBPEXEZMUG……
Spruch Nummer…… > abcdefghijkl……
Spruch Nr……… > abcdefgm……
‘h’ = ‘u’ <XOR> key
‘m’ = ‘r’ <XOR> key
‘u’ <XOR> key <XOR> ‘r’ <XOR> key -> ‘u’ <XOR> ‘r’ !!!
(“General report on Tunny”)

12. “Double Δ”
Human language tends to use double letters, whereas these are less common in crypto-text.

13. “Double Δ”
Human language tends to use double letters, whereas these are less common in crypto-text.
Example from previous example text: “Message”.

14. “Double Δ”
Human language tends to use double letters, whereas these are less common in crypto-text.
Example from previous example text: “Message”.
Teletype text tends to use double control characters, to ensure that a control character is not lost; loss of a control character can result in parts of the message being garbled.

15. “Double Δ”
Human language tends to use double letters, whereas these are less common in crypto-text.
Example from previous example text: “Message”.
Teletype text tends to use double control characters, to ensure that a control character is not lost; loss of a control character can result in parts of the message being garbled.
Example from previous example text: repeated letter shift.

16. “Double Δ”
Human language tends to use double letters, whereas these are less common in crypto-text.
Example from previous example text: “Message”.
Teletype text tends to use double control characters, to ensure that a control character is not lost; loss of a control character can result in parts of the message being garbled.
Example from previous example text: repeated letter shift.
At the point where the key being sought matches the key which was used it is possible to detect these doubles by using a so-called “double Δ”.

17. “Double Δ”
Human language tends to use double letters, whereas these are less common in crypto-text.
Example from previous example text: “Message”.
Teletype text tends to use double control characters, to ensure that a control character is not lost; loss of a control character can result in parts of the message being garbled.
Example from previous example text: repeated letter shift.
At the point where the key being sought matches the key which was used it is possible to detect these doubles by using a so-called “double Δ”.
Key(n) <XOR> Message(n) <XOR> Key(n+1) <XOR> Message(n+1) = 0 !!!

18. <cryptotext> XOR <key> = “Message”.

19. Double Δ <sp>XOR<cr>XOR<E>XOR<F> = 0

20. Double Δ <sp>XOR<cr>XOR<E>XOR<F> = 0

21. <cryptotext> XOR <key1,2,3,4,. 13> = <decrypt1,2,3,4,

23. A B C D E F G H I J K L M : Key= 1
ls ls M E S S A G E cr cr lf lf : DD= 4
B C D E F G H I J K L M A : Key= 2
S cr fs D D L F cr N N Y N X : DD= 2
C D E F G H I J K L M A B : Key= 3
L K W S V M ls S cr Z fs W U : DD= 0
D E F G H I J K L M A B C : Key= 4
Y U ls L T C L E Y ls sp D T : DD= 0
E F G H I J K L M A B C D : Key= 5
X J cr M lf A P M fs nl V V Q : DD= 1
F G H I J K L M A B C D E : Key= 6
Z M I C K U J L sp G D B ls : DD= 0
G H I J K L M A B C D E F : Key= 7
I L H A J G S F V F C Z W : DD= 0
H I J K L M A B C D E F G : Key= 8
cr nl B U P H G Q D R I X sp : DD= 0
I J K L M A B C D E F G H : Key= 9
G F X G O J nl nl C lf R R R : DD= 3
J K L M A B C D E F G H I : Key= 10
Q D nl H U Z Q U I C X sp O : DD= 0
K L M A B C D E F G H I J : Key= 11
W H C J X I T K R B W P Y : DD= 0
L M A B C D E F G H I J K : Key= 12
C G Z Z R E O A X Q E fs Z : DD= 1
M A B C D E F G H I J K L : Key= 13
nl S J I F D H H W S N ls N : DD= 1

27. “The Index of Coincidence” (“IC”)
Σ(fi * (fi-1))
N(N-1)

28. “The Index of Coincidence” (“IC”) N(N-1)
Σ(fi * (fi-1))
N(N-1)
where i is in the range 1 to 26, and represents the
number of unique letters in the sample,

29. “The Index of Coincidence” (“IC”) N(N-1)
Σ(fi * (fi-1))
N(N-1)
where i is in the range 1 to 26, and represents the
number of unique letters in the sample,
fi is the number of occurrences of the ith letter of
the alphabet in the sample, and,

30. “The Index of Coincidence” (“IC”) N(N-1)
Σ(fi * (fi-1))
N(N-1)
where i is in the range 1 to 26, and represents the
number of unique letters in the sample,
fi is the number of occurrences of the ith letter of
the alphabet in the sample, and,
N is the total count of the letters in the sample.

34. Hartelijk bedankt voor uw aandacht!
Vielen Dank für Ihre Aufmerksamkeit!