Introduction to Cryptographic System, Cryptography and its history

 

Cryptographic System

In this post, we will see the description of the content on the cryptographic system, cryptography and its history, and many more.

Introduction to Cryptographic System

Security

Security means the protection of systems and information from harm, theft, and various unauthorized access. 

It is the process of preventing and detecting unauthorized access to the system. 

It is measured in four basic ways such as evaluation which helps to assess the possible risks and predictions for their removal, protection which helps to prevent the attacks to reduce the possibility of the compromising system, discovery which identifies the attack and answers where the recovery with the possibility of further work or restoration of the system is done respectively. 

Three areas are developed for maintaining security which is CIA Confidentiality, Integrity, and Availability.

The CIA Triad  

Confidentiality

CIA Triad is a security model which has been developed to help people to think about various parts of IT Security. 

Confidentiality is one of the important parts of the CIA which is developed to protect sensitive information from harmful factors or persons and provides access only to the authorized users. 

Users should also be very careful about the things where sensitive data is transmitted to complete a reaction. 

Biometric verification, security tokens, and digital certificates are some of the ways of confidentiality.

Integrity

This is the second component of the CIA triad which implies that the information should be complete and should not be altered by an unauthorized person or access. 

Consistency, accuracy, and trustworthiness of the data should be maintained over its life cycle. 

Security should be provided to data and files if any type of disastrous event occurs.

Availability 

This is the third and final component of the CIA triad which implies that the necessary information should be made available to the authorized people. 

Authentication mechanisms, access channels, and systems should work properly for the generation of information which they protect and implement it's available when it is needed. 

The devices that are working should be regularly checked and monitored cause complications in the device may cause hardware failures due to which availability may not be maintained.

Cryptography 

Cryptography is the process of converting plain text into ciphertext or unreadable form which can only be understood by the receiver or the person who has access to it. 

Basically, is also known as the encryption and decryption of text and messages. 

Similarly, it has been used for secure communication between people for more than a thousand years. 

Moreover, it plays a vital role in securing communication between different multiple entities. 

Cryptanalysis is the science of converting cipher text into plain text and the person involved in cryptanalysts are also known as attackers who work in breaking down the security. 

Cryptology is the study of cryptography and cryptanalysis. Its aim is to develop a method or technique to accomplish tasks even in the presence of faults and errors and trials.

Cryptography

Key terms for Cryptography 

Encryption- It is the process of changing plain text into an unreadable or unrecognizable form using different alphabets. 

Decryption- It is the process of changing encrypted messages into readable form. 

Cipher- It is a process of scrambling the letter of messages. 

Code- It is a process of scrambling words of messages. 

Ciphertext- It is the result of messages after encryption. 

Plaintext- It is the messages needed to be encrypted. 

Key- A complex sequence of alphabets, shapes, etc. used to decrypt the encrypted data.

Encryption and Decryption Algorithm

History of Cryptography

In the early days, cryptography was simply the writing of messages as most people couldn’t understand those days. 

Cryptography derives from two Greek words that are Kryptos and graphein which means hidden and writing. 

Before it was concerned with converting messages into unreadable form during the time when the message was carried from one place to another. 

Some of the countries where cryptographic systems were first evolved and developed are described below:

The evolvement of Cryptography in Egypt

As per the source, it is known that firstly cryptography originated in the Egyptian town called Menent Khufu on the tomb of nobleman Khnumhotep II nearly 4,000 years ago. 

During 1900 B.C. Khnumhotep’s scribe drew his master’s life in his tomb. As he drew the hieroglyphics he used several different variety symbols to obscure the meaning of the inscriptions. 

This type of method is an example of a substitution cipher, which is the type of cipher system which substitutes the symbol or character for another one. 

After the growing evolvement of Egyptian culture, the hieroglyphic substitution method started becoming common and was easily broken down by the people who could read and write. 

This method was developed by people from Scribe’s community to impress the people by showing that they could write messages and codes at a higher level.

The evolvement of Cryptography in Greece 

In about 500 B.C a community of people in Greece called Spartans developed a device called Scytale, which was used for sending and receiving secret messages. 

The shape of the device was cylindrical in which a narrow strip of parchment was wounded. The message was then written on the parchment length-wise. 

Once it was unwounded then the message was unable to be read or understood. 

In simple language, we can understand that the people of Greece came up with an idea where they would wrap a tape around a stick and then write the message or information on the wound tape, and as soon as the message was unwounded then the message was unable to understand. 

To receive the message, an identical cylinder was needed with the same diameter than only the message could be deciphered. 

Scytale is an example of transposition cipher, which is the type of cipher system that changes the order of the characters than rather changing the character itself. 

In today’s world, Scytale can easily be decrypted but before 2,500 years ago only a limited % of people used to read and write which helped the Spartans for a secure method of communication.

The evolvement of Cryptography in Rome

The method of Cryptography which was used by the people of Rome is known as Caesar Shift Cipher. 

It was invented by Julius Caesar 2,000 years ago for the use of military communication services. 

Caesar, who was the commander of the Roman army during that time, solved the problem of secure communication with his troops by inventing this method. 

The secret message of the military was always overtaken by the enemies so he developed the substitution cipher method in which he substituted letters for different letters and the people who could understand can only decipher the code or messages and it could only be deciphered by his troops which gave the Roman army a huge advantage and benefit during the war and won much war due to this. 

Caesar used to shift the letters typically by some predetermined number. 

The number which he used to be the cipher key of the algorithm. 

A randomized order of substitutions yields a much more amount of security due to the possible amount of orderings. 

Symmetric Cipher

In symmetric cipher key encryption, the same key is used for both the encryption and decryption processes. 

This system was the only system used earlier for discovering and developing the public key. 

A safe way of data transfer must be used to move the secret key between the sender and the receiver in symmetric encryption. 

One of the advantages of symmetric cipher is, that it doesn’t consume more computing power and its working capacity is very high with fast speed. 

It takes place in two modes that are block ciphers and stream ciphers. 

In the block cipher mode, the whole data is divided into several blocks and the data is based on the block length and the key is used for encryption. 

In-stream ciphers data is divided as small as single bits and randomized after that encryption takes place. They are much faster compared to asymmetric cipher systems. 

Different types of evaluation which take place in symmetric cipher are The DES Algorithm, Triple DES algorithm, The AES Algorithm, and Blowfish Algorithm.

Asymmetric Cipher

In the asymmetric cipher process, different types of keys are used for both the encryption and decryption processes. 

One key is public and the other one is the private key. 

The public key is used for encrypting the message whereas the private key is used for decrypting the given message. 

The public key is known by all whereas the private key is known only by the receiver or who has the permission to get through access. 

Both the keys are generated by the receiver. 

The public key is distributed to the sender through a public-key distribution channel. It uses mathematical functions for encryption and decryption process whereas in symmetric cipher substitution and permutation symbols are used. 

It is very slow and very complicated in calculation compared to symmetric encryption. 

It deals with the plain text as a group of numbers that are manipulated in mathematics while the plain text in symmetric cipher deals with symbols and characters. 

So the nature of the data determines the system of the encryption type. And every system has its own uses. 

An asymmetric key is used for authentication, digital signature, and secret key changes. 

Caesar cipher

Caesar cipher is one of the oldest methods for encryption and decryption process. 

This method is based on a monoalphabetic order. 

Similarly, it is the symmetric type of cryptosystem which uses a single key for both encryption and decryption processes. 

It was invented and used by the Roman ruler Julius Caesar around (100 B.C. – 44B.C.). 

Caesar cipher is a very simple cipher method for communication. It was firstly used by Julius Caesar for contacting his generals at the time of war. 

Moreover, it is a type of substitution cipher in which each letter in the plaintext is ‘shifted’ three places down the actual alphabet. 

The reason for choosing 3 as the key to the cipher system is unknown any other integer value could have been chosen. 

Also, it operates on a modulo 26, so it generally has a set of 26 distinct keys for performing operations. It uses the key from 0 to 25.

Advantages: 

    • It is easy to perform and protect. 

    • It is easy to memorize and implement. 

    • It does not have lengthy words.

    • It only requires a few computing sources. 

Disadvantages: 

    • It can easily be broken. 

    • It is vulnerable to brute-force attacks. 

    • It can only provide minimum security of information. 

    • The letter pattern provides a clue for deciphering the text. 

Rail Fence Cipher

Rail Fence Cipher is one of the basic forms of Transposition cipher. It is inspired by Polybius square modeling. 

In this cipher, the plain text is written downwards on successive “rails” of an imaginary fence, then moving up when we get to the bottom. The message is then read off in rows. The message is then read off in rows. It involves the technique of writing plain text as a sequence of diagonals and reading it row-by-row to produce a ciphertext. 

The ciphertext can be obtained by taking a certain set of characters in the line that has already been determined. 

It is also known as a zigzag method in which the keys are represented diagonally.

Advantages: 

    • It is easy to remember. 

    • It does not require a lengthy process. 

Disadvantages: 

    • It can easily be broken by a brute force attack. 

    • It is not strong and contains a limited number of keys. 

    • It does not provide communication security. 

    • It cannot be used to encrypt images containing large areas of a single color.

Development of a new Cryptographic algorithm

Caesar cipher and Rail Fence cipher are one of the most popular and oldest methods used for the encryption and decryption process. 

They are an easy type of symmetrical algorithm. 

They do not require a complex form of the algorithm during operation due to which it can easily be broken. 

Various methods and ways to crack the ciphertext using frequency analysis and words patterning have been implemented over time to decrypt the messages and generate secret information. 

Due to its limited numbers, it has become very vulnerable to brute force attacks to match the frequency distribution of letters. So, researchers are working on various ways to modify the algorithm process and make it safe from various attacks. 

The methodology that has been used to modify the algorithm process is by encrypting and decrypting the process multiple times, adding other algorithm techniques, and combining them for a strong algorithm process so it will be hard to crack the algorithm. 

Along, with the mentioned methods it can also be modified using some mathematical operations during the generation of key, encryption, and decryption process on which my algorithm is based. 

The approach algorithm used in this project is based on the research report of Baljit Saini, a lecturer in the computer department of K.D. Polytechnic. 

The research is based on the works where Caesar cipher and Rail Fence cipher are combined with each other in which Caesar cipher is encrypted first using a mathematical process and is again encrypted using the Rail Fence cipher process which will make the process complex and is decrypted by reversing the process. 

Firstly, decrypting the process using the Rail Fence cipher and then using the mathematical process for the decryption of Caesar cipher to get the plain text.

The new methodology for modified Caesar and Real Fence cipher

The newly developed algorithm called modified Caesar and Real Fence cipher is used to prevent brute force attacks. 

Both substitution and transposition methods are used to encrypt the data strongly. The ciphertext generated by this algorithm will be difficult to break. 

The new methodology used in this algorithm is created by inserting a plain text and an encryption key where the encryption key uses an integer number which is based on the position of the alphabet in the numeric table and a mathematical operation is done and is encrypted again using rail fence cipher and for the decryption process ciphertext value is inserted for decryption and a reversal mathematical value is applied for the final decryption.

The new algorithm which is used for encrypting a plain text into ciphertext is by using a function called C1= (P+K) mod 26 along with the combination of rail fence cipher. 

The new algorithm which is used for decrypting a ciphertext into plain text is by using a mathematical function called P=(C1-K) mod 26 along with the combination of rail fence cipher to generate a plain text.

Critical Evaluation of the proposed algorithm

The newly developed algorithm named modified Caesar and Rail Fence method is developed to make the encryption process strong and protect it from different vulnerable attacks. 

It is made with a double encryption process. 

The proposed algorithm is critically analyzed with strengths, weaknesses, and major application areas used. 

Strength of the developed algorithm: 

    • It is stronger against brute force attacks. 

    • It is difficult to crypt-analyze for the attackers who try to break the cipher. 

    • It overcomes the limitations of simple Caesar and Rail Fence cipher. 

    • Cipher text generated by the combination of two algorithms is stronger and hard to decrypt. 

    • They can encrypt data strongly and is secure for communication.

Weakness of the proposed algorithm:

    • It is a lengthy process due to the combination of two ciphers. 

    • It is quite difficult to remember because of its multi encryption process. 

    • It is time-consuming because of the combination of two ciphers. 

    • It has a limited number of keys to encrypt the message. 

    • If a single character is mistaken then the whole process goes to become wrong.

Application areas for Modified Caesar and Rail Fence cipher

Modified Caesar and Rail Fence cipher is the developed and combined version of Caesar and Rail Fence cipher. 

The modified Caesar cipher and Rail Fence cipher can encrypt data strongly. 

It is more secure and could be used in the transmission of data from various protocols such as FTP, and SMTP which are used to transmit data from sender to receiver. 

It can also be implemented to encrypt confidential data such as student records, files of different organizations, etc. 

It can also be used in banks for providing a strong password. It can also be used for setting up the connection between SSH protocol.