These days, the rise of the internet has led to an increase in the sharing of information in the online space. A lot of this information is private and could be potentially harmful to the individual if caught in the wrong hands. This is why security protocols such as VPNs and encryptions are in place, which leads us to the subject of discussion.

The practice is cryptography refers to the act of writing or solving codes and studying techniques for secure communication online. A cryptosystem, also known as a cipher system, is a series of algorithms needed to implement a security service, such as confidentiality.

Typically, a cryptosystem consists of three algorithms:

- Key generation
- Encryption
- Decryption

In a legitimate cryptographic system that is fully functional, these algorithms are combined with a key that consists of a string of numbers or characters. The algorithm uses the key to select one relationship between plaintext and ciphertext out of the many possible relationships the algorithm provides. This determines what the algorithm yields as a result.

In this guide, we’re covering in detail the different elements that make up a cryptographic system. With this basis of knowledge, you’ll be well on your way to building your own encryption algorithm.

## Basic Elements of a Cryptosystem

There are various components that make up a basic cryptosystem:

- Plaintext: This refers to the data that is being protected as it is transferred.
- Encryption algorithm: The mathematical process that produces a ciphertext for any given plaintext and encryption key. This cryptographic algorithm combines the plaintext and an encryption key to produce a ciphertext.
- Ciphertext: The scrambled, coded version of the plaintext produced by the encryption algorithm using a specific encryption key. The ciphertext flows on a public channel, meaning it can be intercepted or compromised by anyone who has access to the channel.
- Decryption algorithm: The decryption algorithm essentially reverses the encryption algorithm. It is a mathematical process that produces a unique plaintext for any given ciphertext and decryption key. This cryptographic algorithm takes a ciphertext and a decryption key and produces a plaintext.
- Encryption key: The value the sender knows. They input the encryption key into the encryption algorithm along with the plaintext in order to compute the ciphertext.
- Decryption key: The value that the receiver knows. They input the decryption key into the decryption algorithm along with the ciphertext in order to compute the plaintext.

## Secret Key vs. Public Key Cryptography

There are two main types of cryptographic processes:

- Symmetric: Also known as or secret key algorithms, the same key value is used in both the encryption and decryption calculations.
- Asymmetric: Also known as public-key algorithms, in which a different key is used in the decryption calculation than was used in the encryption calculation.

What is the difference between secret key and public-key cryptography?

### Symmetric Cryptography

Secret key cryptography, also known as symmetric cryptography, uses a conventional algorithm such as the Data Encryption Standard (DES) algorithm or the Advanced Encryption Standard (AES) algorithm. Two parties who are using a conventional algorithm must be using the same algorithm. In addition, the cryptographic key that the sending party uses to encipher the data must be available to the receiving party to decipher the data.

### Asymmetric Cryptography

Each party in a public key (asymmetric) cryptography system has a pair of keys. One key is public and is published, and the other key is private. It is also called asymmetric cryptography because the public key and private key are not identical. The sending party looks up the receiving party’s public key and uses it to encipher the data. The receiving party then uses its private key to decipher the data. It is critically important to maintain the secrecy of the private key.

Public key cryptography requires complex mathematical calculations. These types of systems are not used for enciphering large amounts of data. Instead, they’re used to encipher and decipher symmetric keys that are sent between two parties or systems.

A common use of public-key cryptography systems is to generate and verify digital signatures on electronic documents. For example, the sender will use his or her private key to generate a digital signature. The receiver then uses the sender’s public key to verify the identity of the sender. Because of this multi-level functions of security, the digital signature is legitimate and given authenticity, thus being able to act as a legal replacement to a handwritten signature.

Want to learn more about cryptography? We suggest going on forums dedicated to online security and building your own encryption key system in order to understand the ins and outs of the process. Communicate with others in order to test your algorithm and see what needs modifying. The ultimate goal is to have the highest levels of security possible to protect your information and what you send and receive from others.