Caesar cipher
1. Introduction
With the rapid development of digital data exchange in electronic form, information security is becoming increasingly important in the storage and transmission of data. Therefore, data exchange must be encrypted. Encryption is the process of encoding a message so that only the intended recipient can read it. Caesar's cipher is a mono-alphabetical cipher. This is a type of wildcard cipher, where each letter in the plaintext is replaced with another letter, shifted by a fixed number of positions in the alphabet. Encryption is represented using modular arithmetic.
With the advancement of internet technology, many security problems arise. Security is a big issue and protecting sensitive data is very important so that data cannot be altered or used for illegal purposes. For example, in Internet banking, in the electronic booking system, in the media, data security is a very important issue. In most cases, the provider must ensure the security of their infrastructure and the protection of their customer's personal data and applications, while the customer must ensure that the cloud provider has taken appropriate security measures to protect their information. To avoid this situation, it is necessary to convert the data to an unreadable form on the sender side, and then convert this data back to a readable form on the receiver side. In this way,the problem of keeping data confidential is relevant both for large companies and for each person. The technique and science of creating unreadable data or ciphers such that only an authorized person can read the data is called cryptography.
2. Cryptography
Cryptography is the science of protecting information from unwanted persons by converting it into a form that is not recognized by attackers during storage and transmission. Cryptology is not new, it has been around for over 2000 years. The word cryptology comes from two Greek words: kryptos, meaning hidden or secret, and graphein, meaning to write. Cryptology is a science that allows communication to be made incomprehensible to everyone except the intended recipients. In the language of cryptography, the message that a person intends to send is called clear text, while the actual message sent is called cipher text. There are two main categories of cryptography (asymmetric and symmetric encryption methods) depending on the type of security keys used to encrypt / decrypt data.
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The Caesar cipher is the simplest type of cipher and is most commonly used. The permutation method is most often combined with other techniques. Both replacement and rearrangement encryption is easily accomplished using computers. The combination of these two classical methods provides a more secure and reliable cipher.
The final ciphertext is so powerful that it is very difficult to crack. The above second method (algorithm) is a combination of permutation and substitution methods that provides a much more secure cipher.