• Aucun résultat trouvé

Episode 09 – The Caesar cipher European section – Season 3

N/A
N/A
Info
Télécharger
Protected

Academic year: 2022

Partager "Episode 09 – The Caesar cipher European section – Season 3"

Copied!
8
0
0

Chargement.... (Voir le texte intégral maintenant)

Texte intégral

(1)

Episode 09 – The Caesar cipher

European section – Season 3

Episode 09 – The Caesar cipher

(2)

Why Caesar ?

(3)

Suetonius, Life of Julius Caesar

“If he had anything

confidential to say, he wrote it in cipher, that is, by so changing the order of the letters of the alphabet, that not a word could be made out. If anyone wishes to decipher these, and get at their meaning, he must substitute the fourth letter of the alphabet, namely D, for A, and so with the others.”

Episode 09 – The Caesar cipher

(4)

A Caesar cipher with a shift of three

(5)

An example

v e n i v i d i v i c i Y H Q L Y L G L Y L F L

Episode 09 – The Caesar cipher

(6)

The implementation chain

Sender Receiver

This is plain text, that anyone could read if it were sent without being en- coded.

This is plain text, that anyone could read if it were sent without being en- coded.

Plaintext Plaintext

Wklv lv hq

hqfubswhg whaw xquhdgdeoh zlwkrxw iluvw ehlqj ghfubswhg.

Algorithm Ciphertext Algorithm

(7)

Advantages and drawbacks

Easy to implement.

Offers a minimun of secrecy.

Easy to decipher.

Episode 09 – The Caesar cipher

(8)

Your tasks

1

Choose a partner far away in the class.

2

Decide on a shift.

3

Write a short message in plain text

(lower-case), then encipher it (upper-case).

4

Send the ciphertext to its destination, trough the teacher.

5

Decode the message you received.

6

Try to decode intercepted messages without

Références

Télécharger maintenant ( PDF - 8 Page - 361.14 KB )

Documents relatifs

Could it be the case that if I am right my opponents will be pleased? A rejoinder to Johnson-Laird, Byrne and Girotto

It may, however, be worth pointing out that in case the operation of modulation leaves the core meaning unaltered, the possibilities of the "conditional interpretation"

To diagnose, or not to diagnose: that is the question

S everal years ago, at the urging of some nonmedical friends, a small group of physicians and our spouses created a new board game called “Diagnosis.” Each player was a

2 The Cipher

As with the description of the cipher, we can describe the key schedule in either standard or bitslice mode. We will give the substantive description for the latter case... Our

Episode 13 –The Beale Ciphers European section – Season 3

Thomas Beale visits Robert Morriss and stays at his hotel for a few months from January 1820.... Act 2

The Vigenère cipher

so-alled Vigenère ipher, but he did devise a stronger autokey based on the same table.. Messages are enrypted with the help of a tabula reta, also alled

Session 14 – The Vigenère cipher European section – Season 03

EBGIQ LSVRY ENJON CIUZC NNQPZ PCPQF LHIOB THVRC XITXG YAEYL NYPDP LNGCY XUPCK THFGM YXGBD FFNIS YZQBR FHCDC WSYRY ENJOK THFSL PPKDY MFAMM YWGXR CUVOQ ZHKCR SUVSL EBGWM CHKXE TNYSJ

Session 15 – Breaking the Vigenère cipher European section – Season 3

Something began when the Guild of Assassins enrolled Mister Teatime, who saw things differently from other people, and one of the ways that he saw things differently from other

Episode 18 – The Tower of Hanoi European section – Season 3

The priests of Brahma, acting out the command of an ancient prophecy, have been moving these disks from the first post to the third, in accordance with the following rules :...