ANSARI MUKHTAR

Caesar Cipher Introduction The Caesar cipher is one of the earliest known and simplest ciphers. It is a type of substitution cipher in which each letter in the plaintext is 'shifted' a certain number of places down the alphabet. For example, with a shift of 1, A would be replaced by B, B would become C, and so on. The method is named after Julius Caesar, who apparently used it to communicate with his generals. More complex encryption schemes such as the Vigenère cipher employ the Caesar cipher as one element of the encryption process. The widely known ROT13 'encryption' is simply a Caesar cipher with an offset of 13. The Caesar cipher offers essentially no communication security, and it will be shown that it can be easily broken even by hand. Example To pass an encrypted message from one person to another, it is first necessary that both parties have the 'key' for the cipher, so that the sender may encrypt it and the receiver may decrypt it...

Product Cipher Example 1 Key Number : Relation I chose the word “Relations” because there is no the same character, so that more produce number key. Number range that I chose was 11-32 Keyword = Dragon Plaintext = computer registration  65-2j/4 Ciphertext = 16523271921944321114247215664292254 Example 2 Key number = Modem   I chose the word “Modem” because I always use the modem to work tasks . Key word = Backpack Range number 51-75 Plainteks = HALUOLEO UNIVERSITY (UNHALU) Ciphertext = 5655686914681214697360711257616065546669735655686970 Example 3 Key number = Mosquito I chose the word “Mosquito” because mosquito is a unique word. Key word = inject Range number = 70-90 Plainteks = SERIAL NUMBER 12/2Q2_2SD Ciphertext = 579846888972987079841287272902573 Example 4 Key number = PROBLEM I chose the word “Problem” because there is no the same character, so that more produce numbe...