What is the Difference Between Symmetric and Asymmetric Encryption?

Most people today are unable to choose the best encryption scheme for their system security. Don’t worry in this article I will be discussing the difference between symmetric and asymmetric encryption. These are the most popular encryption schemes in use today.

Knowing when to choose one over the other can greatly help keep your information and system security.

Before diving into specific differences between these two encryption schemes I would like to explain some basic cryptographic terms to help you understand the rest of the article. So, what is an algorithm?

An algorithm is simply a procedure or a formula for solving a specific problem. From that basic definition, an encryption algorithm is basically a set of mathematical procedure used for performing encryption of a set of data.

Normally this works by converting plaintext into ciphertext using an encryption algorithm and a key.

What is cryptography?

Cryptography is simply a method of using advanced mathematical principles in storing and transmitting data in a concealed form to prevent other parties from reading and processing it. Encryption is heavily used in cryptography to transform normal messages into an unreadable form.

The earliest and most known encryption technique used for ages is Caesar cipher first used by Julius Caesar for his military correspondence. Here are some important cryptographic terms you need to know:

  • Encryption. It is the process of locking up information using cryptography making it unreadable to persons without the knowledge of the encryption scheme used or the key.
  • Decryption. This is the reverse process of encryption. It is a way of unlocking the encrypted information into a readable form using a cryptographic key and an algorithm.
  • Key. This is simply a secret like a password used to encrypt and decrypt information.

Symmetrical Encryption

This is the most basic kind of encryption that involves only one secret key to encrypt and decrypt information. Symmetrical encryption uses a secret key that can either be a number, a word or a string of random letters. It is used together with the plaintext of the message to transform the content into ciphertext.

Symmetrical Encryption Example

Note that both the sender and the recipient should know the secret key that is to be used for encryption and decryption of their messages. The most popular examples of symmetric encryption include AES, DES, RC4, RC5, RC6, and Blowfish. Most widely used symmetric algorithms include: AES-128, AES-192, and AES-256.

The only disadvantage of the symmetric key encryption is that both parties have to exchange the key to be used for encryption and decryption beforehand.

Asymmetrical Encryption

Asymmetrical encryption is also known as public key cryptography. This is a newer method of encryption compared to symmetric encryption. Asymmetric encryption uses two keys to encrypt plaintext into ciphertext. Keys are normally shared over large networks like the internet.

Asymmetrical Encryption Example

The reason why asymmetrical encryption uses two related keys is to enhance security since anyone with a secret key can decrypt the message. A public key is freely available to anyone who may want to send you a message. The second key private key is kept a secret.

A message encrypted using a public key can only be decrypted using a private key, also, a message encrypted using a private key can only be decrypted using a public key.

Asymmetric encryption was introduced to solve the problem of having to share the key in symmetric encryption model. This worked by using a pair of public-private keys.

Asymmetric encryption is mainly used today in ensuring the security of information transmitted during communication for example, in digital certificates. The most popular asymmetric key encryption algorithms include RSA, DSA, Elliptic curve techniques, ElGamal, and PKCs.

Now that you understand the basic cryptographic concepts, let’s look at how these two encryption techniques compare to one another.

Difference Between Symmetric and Asymmetric Encryption

  • Symmetric encryption uses a single key that needs to be shared among the people communicating whereas asymmetric encryption uses a pair of public keys and a private key to encrypt and decrypt messages during communication.
  • Symmetric encryption is an old technique while asymmetric encryption is relatively new.
  • Asymmetric encryption takes relatively more time than the symmetric encryption.

Now I want to hear from you.

What do you think of symmetric vs asymmetric encryption?

Or maybe I missed an important difference between symmetric and asymmetric encryption.

Either way, let me know by leaving a comment below.


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