Protecting confidential data in a digital world is especially challenging, but especially important, too. Files, messages, credit card information, and other sharable data are targets of cybercrime, both for individuals and for corporations. Businesses, governments, and all kinds of organizations use cryptography to keep their information private and secure while still sharing, managing, and processing that data.
Encryption algorithms are a specific method of cryptography that allows us to encode information for authorized users only. Encryption is essential to digital security, and depending on the level of security needed, different types of encryption methods and algorithms are used.
How do encryption algorithms work?
Encryption algorithms are mathematical formulas that transform plaintext into ciphertext. Plaintext is what the message looks like unaltered, but ciphertext scrambles the message to a point where it’s unreadable—unless you have the right authorization to decrypt the code back into plaintext. Put simply, algorithms make encrypting and decrypting code possible, specifically between the correct users. These algorithms are written into software for computer systems and networks.
Types of encryption
Before dissecting the different types of algorithms, let’s review the difference between symmetric and asymmetric encryption.
When a message or file is encrypted, it can only be unscrambled and read if the receiver of the message has the correct password or code. Codes used to encrypt or decrypt are often referred to as keys, and without the proper cryptographic key, a recipient has no way of accessing an encrypted file.
With symmetric encryption, there is only one key that is used by both the owner and the recipient. Symmetric encryption uses either stream ciphers (encrypting bits of data one at a time) or block ciphers (encrypting a certain number of bits and grouping them into a single unit).
Think of it as sending someone a package that’s locked. No one can open the package without the key, including hackers, but you also have to find a secure way to send or share the key. In the case of computers, both computers would need to have the key to open certain files.
One advantage of this type of encryption is how efficiently large amounts of data can be sent. Only having one key doesn’t require as much mathematical computing. Symmetric encryption is also extremely secure if you have a trusted algorithm.
The issue with symmetric encryption is sharing the key with others without compromising security. If, for example, the owner of an encrypted file sends the key over email, a hacker can hack into their email and use the key to access shared information, defeating the purpose of encrypting something to begin with. The key is often shared in person to mitigate such risk, but this isn’t always a realistic option for the extent of the internet. This issue calls for a key hierarchy or a way to manage the keys being used in huge bouts of data.
Asymmetric encryption, also known as public-key encryption, involves two keys. The key that encrypts a message or file is public, meaning it can be exchanged with anyone. However, the second key is private and is the only key that can decrypt the message or file.
Think of asymmetric encryption like a deposit box. Anyone can leave a letter, but only the owner of the private key can open the box to access the private information. This is most commonly used to exchange information and data on the internet.
The most obvious advantage of public-key encryption is its security and convenience. Instead of having a “secret code” that only two specific sources know, data can be safely exchanged with more people online. Asymmetric encryption also uses Public Key Infrastructure (PKI), which protects communications between the server and the client using digital certificates, which make it easier to verify that the recipient is coming from the correct sender.
The downside to asymmetric encryption is that the keys only go one direction, meaning a correspondence would require both parties to have their own set keys, one public and one private. In other words, every recipient needing to decrypt a message needs their own deposit box with a private key. Unlike symmetric encryption, the asymmetric encryption method is also more mathematically complex, which can slow down processing time.
3 main types of algorithms
With data being exchanged constantly online, both symmetric and asymmetric encryption is used today to verify, authenticate, and protect users. Depending on the level of security necessary, who needs access to data, the type of requests being made, etc., different encryption algorithms are better for certain scenarios. Some are more advanced than others, but the following systems are the most common and secure types of encryption.
Triple Data Encryption Standard (Triple-DES)
One of the first major algorithms used was the Data Encryption Standard (DES), a type of symmetric encryption. It was the standard for electronic communications. Though DES provided a solid foundation for encryption, it could be hacked in a matter of hours and couldn’t keep up with modern computing.
Triple-DES was much more secure because it overcame the small keyspace of DES, and it eventually became the standard symmetric encryption algorithm for a time, specifically in the 1990s. It weaved its way into cryptographic protocols, too, such as SSH and TLS. Triple-DES (or 3DES) uses the cipher of DES three times over to encrypt data, which allows for multiple key lengths despite only using 56-bit keys.
- Symmetric encryption
- Uses 64-bit blocks, but only 56-bits are secure
- Runs DES 3 separate times with 3 separate keys
Triple-DES is one of the most efficient algorithms to implement. In its prime, 3DES changed security and helped resolve some of the biggest security leaks of DES. It still works for some hardware security encryptions.
In the face of more secure encryption algorithms, Triple-DES is becoming more and more obsolete. Though it can compute more than DES, 3DES can only work with 64-bit blocks, which doesn’t keep up with most modern organizations. Most big companies and organizations use different symmetric encryption methods.
During the peak of Triple-DES use, big names like Microsoft and Firefox used Triple-DES for data security. Financial, payment, and other private services still use Triple-DES, though it’s unlikely they will continue using it.
Advanced Encryption Standard (AES)
The Advanced Encryption Standard (AES) is a type of symmetric encryption that is considered both the most unbreakable algorithm and the global standard of security. AES dethroned Triple-DES due to its higher computing capabilities and advanced security.
- Compatible with both hardware and software
- Uses 3 different key lengths: 128, 192, and 256-bit keys
- Symmetric block cipher
- Encrypted in 128-bit blocks
There are no guarantees in the cyberworld, but to date, AES has yet to be cracked as far as anyone knows. With the ability to use a 256-bit key length, it’s one of the most secure forms of encryption. In fact, it would take billions of years to crack even a 128-bit encryption.
Even though it’s more powerful than both DES and Triple-DES, it is a bit harder to implement. It’s also slower due to the key size, which can sometimes hinder communication.
The U.S. government uses this algorithm to keep all sorts of information private and secure. From government computers to cybersecurity, AES is an essential tool for keeping data classified. AES is truthfully used everywhere: solid-state drives (SSDs), WiFi in local area networks, cloud storage, internet browsers, and more.
Rivest-Shamir-Adleman (RSA) is a public-key encryption algorithm and is the primary way data is securely sent over the internet. As an asymmetric encryption method, RSA uses two keys, one for public encryption and one for private decryption. A defining element of RSA is how the algorithm is used: by factoring prime numbers.
- Create and verify digital signatures
- Supports key sizes 512 bits to 4096 bits
- Asymmetric encryption
This is the best system for communicating with others online, especially when exchanging potentially sensitive information. It’s especially used to verify digital signatures. It’s easy to implement and sharing public keys to online users is relatively easy.
Because RSA is an asymmetric algorithm, it’s notably slower in comparison to symmetric encryption. It also requires more power compared to single-key encryption. Plus, though it’s great for security, if the private key is lost, the data cannot be decrypted.
RSA is used all over online, including web browsers, VPNs, emails, chats, and other communication servers.
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