What is Cryptography?

Cryptography, to most people, seems like a subject that is more related to a history rather than more practical areas like math and science. This stereotype is completely understandable since many people think of ancient Egyptian or Latin letters that are found in history books, rather than examples of modern cryptography. While it is true that cryptography has had a long history, mathematics, specifically algorithms, must be applied to encrypt. In a way, mathematics is the fundamental base for cryptography. Since many people are unaware of the relationship between algorithms and cryptography, I want to explain about their close relationship in this post.
Before getting into the relationship between algorithms and cryptography, I want to clearly set the definition of “cryptography”. Cryptography’s prefix, crypto- comes from a Greek word kruptos, which means hidden. Its suffix, -graphy, comes from a Greek word -graphiā, which means to write. Simply put, cryptography means “secret writing”, To be more specific, it refers to “the enciphering and deciphering of messages in secret code or cipher; also : the computerized encoding and decoding of information”. Cryptography used in ancient times is often referred to as “Classic Cryptography”. In Classic Cryptography, it was commonly used for secret communications and it happened in a more mechanical form that used paper and pen. One might wonder about what good cryptography is in the modern society that we live in today. Surprisingly, cryptography is used and studied as much as, if not, more than the ancient society. Cryptography that is used in the current society, commonly referred as “Modern Cryptography”, is used mostly in computer science.
Cryptography can be divided into two parts: encryption and decipherment. The secret message needs to be able to be enciphered and deciphered between the communicators. That is where algorithms pop up. By creating a specific set of rules, it is highly likely that the message can only be understood by the sender and the reader. It will be extremely hard for an outsider to decipher the message without knowing the encryption key. This is also where the classic cryptography and modern cryptography differs. Classic cryptography used simple techniques that made the message much more prone to an outsider deciphering the message. However, as science and mathematics advanced, techniques and algorithms used in cryptography became much more complicated to cipher. It became so complicated that it is almost impossible to decipher a message without knowing the encryption key. This guarantees the message much more privacy. In my next post, I will be elaborating more on what benefits cryptography brings.
1. Merriam Webster, retrieved from http://www.merriam-webster.com/dictionary/cryptography

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