Encryption is the method by which information is converted into secret code that hides the information’s true meaning. The science of encrypting and decrypting information is called cryptography.

It is a way of scrambling data so that only authorized parties can understand the information. In technical terms, it is the process of converting human-readable plaintext to incomprehensible text, also known as ciphertext. Encryption requires the use of a cryptographic key: a set of mathematical values that both the sender and the recipient of an encrypted message agree on.

Encryption is not an invention of the digital age. History buffs will know that cryptography dates back to as early as Ancient Egypt. In ancient times, secret messages were usually encrypted using symbol replacement.

Types Of Encryption?

The two main kinds of encryption are symmetric encryption and asymmetric encryption. Asymmetric encryption is also known as public key encryption.

In symmetric encryption, there is only one key, and all communicating parties use the same (secret) key for both encryption and decryption.

In asymmetric, or public key, encryption, there are two keys: one key is used for encryption, and a different key is used for decryption. The decryption key is kept private (hence the “private key” name), while the encryption key is shared publicly, for anyone to use (hence the “public key” name). Asymmetric encryption is a foundational technology for TLS (often called SSL).

Encryption Algorithms

There also are various algorithms that can use symmetric or asymmetric encryption. Here are five of the most commonly used encryption algorithms and how they work:

  • AES — The Advanced Encryption Standard is one of the most secure symmetric encryption algorithms that currently exist. It uses ciphers with a 128-bit block size, and key lengths of 128, 192, or 256 bits. AES is the algorithm of choice for multiple organizations including the US government.
  • Triple DES — When the original Data Encryption Standard (DES) became susceptible to attacks, it was replaced by Triple DES. Its name is derived from its use of three 56-bit keys. It’s a symmetric encryption algorithm, but it has fallen out of fashion in recent years with the emergence of more secure options like the aforementioned AES.
  • Blowfish — This encryption algorithm was invented by security expert Bruce Schneier. Like Triple DES, it emerged to replace the outdated DES. It is a symmetric-key block cipher that ranks among the most secure algorithms. Better yet, it can be used by anyone thanks to its public domain status.
  • Twofish — Another invention of Bruce Schneier, TwoFish is the more advanced successor of Blowfish. It is a symmetric encryption algorithm that uses keys up to 256 bits in length. It is not only fast and secure, but it’s in the public domain just like its predecessor.
  • RSA — An asymmetric encryption algorithm, RSA is one of the oldest and most widely used standards for data encryption online. It is relatively slow, but it is regarded as very secure.
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Why Is Data Encryption Necessary?

Privacy: Encryption ensures that no one can read communications or data at rest except the intended recipient or the rightful data owner. This prevents attackers, ad networks, Internet service providers, and in some cases governments from intercepting and reading sensitive data.

Security: Encryption helps prevent data breaches, whether the data is in transit or at rest. If a corporate device is lost or stolen and its hard drive is properly encrypted, the data on that device will still be secure. Similarly, encrypted communications enable the communicating parties to exchange sensitive data without leaking the data.

Data integrity: Encryption also helps prevent malicious behavior such as on-path attacks. When data is transmitted across the Internet, encryption (along with other integrity protections) ensures that what the recipient receives has not been tampered with on the way.

Authentication: Public key encryption, among other things, can be used to establish that a website’s owner owns the private key listed in the website’s TLS certificate. This allows users of the website to be sure that they are connected to the real website (see What is public key encryption? to learn more).

Regulations: For all these reasons, many industry and government regulations require companies that handle user data to keep that data encrypted. Examples of regulatory and compliance standards that require encryption include HIPAA, PCI-DSS, and the GDPR.

Encryption cannot protect you from 100% of attacks. It has flaws and limitations which can be exploited, but you are much more exposed to sleuthing and data harvesting without it.

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