The objective of cryptography is the protection of information so that only the recipient is capable of understanding the information sent. It is possible that a key or coordinate exists that allows the decoding of this information; for this purpose, there are encryption methods or systems that are known only to the recipients.
Cryptography emerged in times of war due to the need to send strategic messages that are key and that opposing factions are unable to understand the message (you can learn more about the development of this with the film The Imitation Game starring Alan Turing during World War II). Currently, cryptography is primarily used by areas of computer science to protect the security of data or communications that are shared primarily on the internet.
Web Cryptography
In addition to protecting information circulating on the internet, cryptography preserves the security of users' communications and operations. This includes account passwords: known cases of SQL injections allowed users' passwords to be revealed; video calls (where Zoom did not encrypt its connections, thus making users' privacy vulnerable); and banking transactions: the case of the first versions of Mercadopago in Chile, where bank cards, expiration dates, and CVV verification codes were exposed to third parties.
In response to the need for communication encryption, Google implemented SEO guidelines to evaluate websites that comply with encryption regulations using HTTPS protocols. Additionally, Let's Encrypt plugins were implemented in cPanel for free integration of the SSL protocol. Let's remember that just a few years ago, implementing these protocols required dedicated IP addresses and the purchase of a certificate (significant costs), in addition to the implementation and adaptability costs.
All of these practices have promoted the development of computer security fields. What today seem like mere steps in development were once deliberate implementations by expert computer security engineers.
Types of Cryptography
Depending on the way messages are encrypted, they can be classified primarily into two dimensions:
Symmetric Cryptography
Symmetric cryptography uses the same key to encrypt and decrypt messages, so that both parties have the key or coordinates to decrypt them.
Asymmetric Cryptography
This method uses two keys: public and private. The public key is accessible to anyone, while the private key is only accessible to the key owner.