I. What is Cryptography?
Do you have a message which is so confidential that you need to send to a certain person but you’re afraid that somebody might read it? Well you better study about CRYPTOGRAPHY. But first what is cryptography? Cryptography is the study of hiding readable messages (plaintext) into a non-readable form (ciphertext). Based on my other source Cryptography is the practice and study of techniques for secure communication in the presence of third parties. To make it simple, Cryptography is used in order to make sure that your messages and data are secured from other elements.
The method of disguising plaintext in such a way as to hide its substance is called encryption. Encrypting plaintext will result to meaningless data called ciphertext. We use encryption in order to hide the information from anyone whom is not intended even if they can see the encrypted data. But maybe you are curious on how your receiver will be able to read the unreadable message? Well if there is encryption, there is also decryption which is the reverse, in other words, moving from ciphertext back to plaintext. But in order to decipher a ciphertext, you should know the key used by the sender. A key is a usually a short string of characters, which is needed to decrypt a certain ciphertext.
Figure 1.1 Encryption and decryption
Cryptography can be strong or weak. Cryptographic strength can be measured in the time it takes for one to recover the plaintext.
The result of strong cryptography is a ciphertext that is very difficult to decipher without possession of the proper decoding tools.
According from another source, Cryptography is where security engineering meets mathematics. It provides us with tools that underlie most modern security protocols. It is widely used in the modern era to protect distributed systems from the wrong thing, or used to protect them in the wrong way.
Cryptography based on my other references is the study of methods to send and receive secret messages. The goal of cryptography to help a sender communicate a message to a receiver without the adversary learning what the message was. We know that there are tons of hackers who would want infiltrate a system and get information. Some will use that information in evil ways, some will sell it to companies and some just do it for fun. That’s why cryptography is very essential to be learned and used especially when you are in the industry of modern technology.
Cryptography is also said to be the science and art of secret writing. It can protect data from unauthorized and unwanted disclosure; it can also authenticate the identity of a user of a program. So why do you think we should study cryptography? Well it is important for us to study cryptography since we are future programmers and future IT professionals because this would help us a lot especially in securing our programs. It will help us to ensure that the programs that we develop are safe from the hackers around us. It will also help us keep our job, imagine that you are responsible for the security of a system and it is infiltrated by hackers, definitely you will lose your job. Therefore as future programmers we should study and use cryptography wisely because this is very powerful but also dangerous in the hands of the wrong.
II. History of Cryptography
No one really knows where or when cryptography started, some believe that it started when more than 3 individuals started to communicate, and when 1 of them wanted to send a message to another without being discovered by the others.
Cryptography is one of the oldest fields of technical study we can find records of, going back at least 4,000 years. Cryptography probably began in or around 2000 B.C. in Egypt, where hieroglyphics were used to decorate the tombs of deceased rulers and kings. These hieroglyphics told the story of the life of the king and proclaimed the great acts of his...
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