The word “encryption” is often used when talking about security. What does encryption mean, and how does it work? We will explain encryption, which is important to understand as the foundation of security measures.
What is Encryption?
Encryption is a technology or method that makes the contents of data unintelligible to third parties by, for example, changing a string of characters according to certain rules.
For example, when you use an inquiry form on a shopping site, in most cases the URL that appears in the browser’s address bar starts with “https” instead of “http”. This HTTPS is a communication technology that adds security features to HTTP. More specifically, a URL that starts with “https” indicates that the web page is in an encrypted communication state using a communication protocol such as SSL or TSL.
In addition, ZIP files, also known as compressed files, can be encrypted with a password. Furthermore, Windows comes standard with a file encryption function for NTFS (one of the file systems) called “Encrypting File System (EFS)”.
In addition, encrypted data cannot be communicated to others unless it can be restored to its original state (called plaintext). Restoring encrypted data to its original state is called “decryption.”
What is a cryptographic key?
The certain rules used in encryption are also called encryption algorithms or transformation algorithms. The “certain data” that controls the steps of this encryption algorithm is called an encryption key. In other words, an encryption key is the data used when encrypting or decrypting.
Using this key, it is possible to encrypt each piece of data using different procedures with the same encryption algorithm. In other words, the role of the key is to make the encryption procedure different for each user while using the same encryption algorithm. This makes it possible to encrypt text and exchange it securely. This type of encryption technology is also used in email and wireless LAN.
What is encryption strength?
Encryption strength refers to how easily a code can be broken. In other words, it indicates how difficult it is to identify the original data by decrypting the ciphertext without using the encryption key. The higher the encryption strength, the more secure the encryption is.
Generally, encryption strength is determined by the type of encryption algorithm or the length of the encryption key. Key length indicates how many bits of the key are used for encryption and decryption. A longer key increases security, but has the disadvantage of taking longer to encrypt and decrypt.
There are two types of encryption methods
There are two main types of encryption methods that use cryptographic keys: “symmetric key cryptography” and “public key cryptography.” Let’s explain the difference between the two.
Common key cryptography
A symmetric key cryptography is an encryption method that uses the same key for encryption and decryption. It is often used for file encryption, etc., and has the advantage of being fast.
When using a shared key for communication, the process is as follows: (1) the sender encrypts the data with the “shared key” and sends it, and (2) the receiver decrypts the received data with the same “shared key” and reads the data.
In this case, the sender must provide the key to the receiver in advance. The key must be handed over securely, since if the key is leaked to a third party, that person may be able to decrypt the encrypted data.
It is also dangerous to distribute the same key to multiple users, as that key would allow them to decrypt all encrypted data, so a key must be generated for each user.
Public Key Cryptography
Public key cryptography is a method that uses two different keys, one for encryption and one for decryption. The key used for encryption is called the “public key” and the key used for decryption is called the “private key.”
The public key is an open key used exclusively for encryption that anyone can obtain, like a padlock that anyone can lock, while the private key is a decryption key that only the recipient holds, and is easier to understand if you think of it as the key to open a padlock.
When using public key cryptography in communications, the process is as follows: (1) the sender obtains the public key made public by the receiver and sends data encrypted using that public key, and (2) the receiver decrypts the received data using a private key held only by the receiver, and then receives the data.
Benefits of encryption
The purpose of encryption is to strengthen security. Web pages encrypted with SSL/TLS are now used all the time, not just when transmitting personal information or making credit card payments, but also on shopping sites and the like.
The advantage of creating such an “always-on SSL” site is that secure communications are made possible, reducing the risk of the information users send being intercepted or of them being redirected to an unintended website and becoming victims of a phishing scam, allowing users to use the Internet with peace of mind.
In the past, data encryption and decryption took time, which led to problems with slower communication and processing speeds. However, now that Internet communication speeds have improved and the way data is processed has changed for HTTP, the speed issue has been resolved. The trend of encrypting various data to ensure security, not just for communication, is likely to continue to expand in the future.