4.1 Classical Encipher Techniques
For the purpose of sending secret messages there was introduced encryption. As encryption get developed few technique were standardized. They are;
Substitution cipher
Transposition cipher
Product cipher
4.1.1 Substitution cipher
Replacing each element of the plaintext into another element is called as substitution cipher.
The most famouse is the Ceaser cipher which was invented by Julius Ceaser. Each letter is replaced by the letter three positions further down the alphabet. (Lai, 2010)
Plan text: ceaser cipher technique
Alphabet: a b c d e f g h i j k l m n o p q r s t u v w x y z
Cipher albhabet: d e f g h i j k l m n o p q r s t u v w x y z a b c
Chiper Text: fhdvhu flskhu whfkqltxh
In using Ceaser Cipher, was easily predicted by having only a small piece of the cipher text. So that Ceaser had to protect even the cipher text. It was kept easy way so that any one can quickly send a meesage in no time. Making the cipher text harder the algorithm had to be taken with the messanger for decryption so there was a big risk in loosing one messager will make all the cipher text to get deciphered by the enimies. So Ceaser made his algorithm easy and simple. (Pfleeger & Pfleeger, 2007)
4.1.2 Transposition cipher
Rearranging the order of elements in the plaintext is known as Transposition cipher. (Lai, 2010)
Columnar transposition is way of arranging plaintext charactors in cloumn wise.
Here is a sample paintext which been put into 4 cloumns. On creation of 4 column they were created raw by raw. When reading it, was read column wise so that its hard to pridict while the number of the columns are unknown. Also to make it more harder the way of reading was chaged rather than reading from first to ...
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...0: Generated keys
Encryption
A user will be selecting a text file to be encrypted. For the completion user will have to select the key pair, private key of the user and public key of the receiver who will decrypt this message. Figure 21, 22 and 23 are evidence of process.
Figure 21: Encryption process
Figure 22: Test text file used for encryption
Figure 23: Encryption output
Decryption
Same as for encryption, decryption process will also need of the private and public keys of both users (private of the receiver who is going to decrypt and public of sender who encrypted the message). The encrypted message will be also located by the user. After providing a location to save the decrypted text, the process will create the file at that location in name of Decipher_text.txt as mention above.
Figure 24: Decryption process
Figure 25: Deciphered text file
The sender would type the message in plaintext (not encrypted) and the letters would be illuminated on a glass screen. With the press of each typewriter key the rotor would shift 1/26 of a revolution giving each letter a different encryption each time, which made the code so difficult to crack. Due to the complexity of the code the enigma became very useful for the Germans for radioing messages to u-boats. The cipher was finally broken when the British were able to capture some key documents from a German warship.
The RSA encryption is related to the cipher of Julius Caesar (1300s) that shifts three letters to encode messages. The cipher of Julius Caesar was used in war to send messages securely. Here is how Caesar encodes his message using the cipher. First Caesar assigned A through Z to 0 through 25. For instance A is zero. Second, add three to each numbers.
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Asymmetric Key Encryption methods are DSA, Diffie Hellman, RSA, Elliptic Curve and DSA. Asymmetric Encryption
S A N P E T R O N I O : C O M P O S I N G -
Over the course of Human evolution people have been coming up with new and inventive ways to communicate with one another. Some of the earliest evidence of human communication is in a cave in France. In 1940 researchers found paintings from the Paleolithic area showing humans communicating by hunting in a systematic fashion(Boundless textbook) . This shows just how far back people have been trying to work together. Now jumping forward to 2016 people today have amazing technologies that will allow them to get in touch with loved ones overseas in a matter of minutes. But how exactly did we go from drawing pictures on our walls to hi-speed internet? Well one man’s invention revolutionized the industry of communication allowing generations to
The code assigned letters in the alphabet and numbers a set of dots (short marks) and dashes (long marks) based on the frequency of use. The code used the English alphabet but they would make the more frequently used letters into the less complex dots and dashes, such as E or A. While the Less frequently used letters such as D or Z got a lot more complex code of dots and dashes. Initially, the code, when transmitted over the telegraph system, was rendered as marks on a piece of paper that the telegraph operator would then translate back into English. Rather quickly. But then the operators became so good at translating the
Need a thesis. The Greeks and Phoenicians were the first developers of the alphabetic glyphs, but then it was later adopted by the Latins, who used it and mixed it with Etruscan characters, including F and S. But G, J, V, U, W, Y, and Z did not exist within their alphabet. By the time the Romans adopted it, J, U, V, and W were the only letters
Codes have been around for centuries ranging from wax, invisible ink, Morse code, the Enigma used by the Germans during World War II and now steganographic. Steganography is the latest form to insidiously hide information over the Internet without a trace of a file being altered. You are able to hide messages within images, voice or music. Steganography is an ancient method of hiding messages. Today messages are hidden in images and music. Steganography can be traced back to the ancient Greek who would write messages on tablets and cover them in wax. This made the tablets look blank and unsuspicious (Kolata, F4). Citizens of ancient civilizations would tattoo messages on their shaved heads. They would then let their hair grown in and travel across enemy lines to deliver the message (Seper, G1). During World War II the Allies placed a ban on flower deliveries with dates, crossword puzzles and even report cards (Kolata, F4) for fear of a message being hidden with in. Steganographers first alter their data by using encryption and then place the image into a pre-select image. Steganographers look for a piece of code that would be the least significant and look the least altered to the human eye (Kolata, F4), being as inconspicuousness and random as possible. This makes the messages undetectable unless you knew that there is a message hidden and you were able to crack the code.
In this example the AES 256 bit cipher is used but you can use other
The length of the key for the encryption can vary from being very short to extremely long, and the length of the message being encrypted. The protection of data being transferred between ATMs and the bank, and the use of cell phones, is the most common everyday encounter with encryption. To encrypt and decrypt information, a cipher is used. In a cipher, there is a set of well-defined steps that can be followed to encrypt and decrypt messages.
Multiplying the selected number by itself (pub times) and rounding of the value based on maximum encrypts the message.To decrypt, the encrypted message is multiplied by itself priv key times (priv times).
ABSTRACT : This paper describes the basic threats to the network security and the basic issues of interest in designing a secure network. it describes the important aspects of network security. A secure network is one which is free of unauthorized entries and hackers. INTRODUCTION
Word processing typically implies the presence of text manipulation functions that extend beyond a basic ability to enter and change text. For the purpose of this module when discussing and explaining word processing features the software Microsoft Office Word (*Word) will be used as the example.