Information Security | Symmetric Cryptography

Cryptography is a method used to communicate or transmitted data securely by converting plain data into a non-readable form and vice-versa. Cryptography is mainly of two types, symmetric and asymmetric cryptography. This article explains to you symmetric cryptography, its method use, available algorithms, and advantage and disadvantages of the same.

What is Symmetric Cryptography?

Symmetric Cryptography is the simple, oldest, and best-known process for encryption and decryption. Symmetric cryptography is also called Symmetric-key encryption or symmetric cryptography. It is a technique of encrypting or hiding data from an attacker by using a secret key. The sender can encrypt data by applying the secret key to the original data, and the receiver can decrypt it by applying the same secret key to encrypted data.

The secret key in symmetric cryptography

Now, What is the secret key used in Symmetric Cryptography?  A secret key can be a number, a word, or just a string of random letters. As discussed earlier, Symmetric Cryptography process the original data, and convert it into scramble data by using the secret key. For decryption, the same secret key is applied to the encrypted data to get the original data. As long as both sender and recipient know the secret key, they can encrypt and decrypt all messages that use this key.

Algorithms of symmetric cryptography

Now we will see algorithms available for symmetric encryption. Blowfish, AES, RC4, DES, RC5, and RC6 are common algorithms of symmetric encryption. The most widely used symmetric algorithm is AES-128, AES-192, and AES-256.

Advantages of symmetric cryptography

This section covers the advantages of Symmetric Cryptography. The main advantage of using Symmetric Cryptography is that the data is extremely secure if encrypted by using this cryptography.  If the secret key is 256-bit key length, it would take about a billion years to guess a key through a brute force attack.

Another advantage of using Symmetric Cryptography is the speed of encryption and decryption. Symmetric Cryptography is Relatively Fast in comparison with public key cryptography. In fact, many solid-state drives, which are typically extremely fast, use symmetric key encryption internally to store data and they are still faster than unencrypted traditional hard drives.

Now, what are the Disadvantages of Symmetric Cryptography? The availability of a secret key with both sender and receiver is a requirement for successful communication. Secret keys are not simple like passwords. They are essentially blocks of gibberish. You need to send those keys to the receiver securely and secretly. Generally, symmetric encryption is used to encrypt personal data rather than send encrypted data to another person due to the difficulty of sharing keys.

The disadvantage of symmetric cryptography

The main problem associated with symmetric cryptography is the handling of secret keys. When someone gets a secret key, they can decrypt everything encrypted with that key. When you're using symmetric encryption for two-way communications, this means that both sides of the conversation get compromised.

These problems are solved using public-key cryptography—public-key cryptography using a pair of keys for encryption and decryption.