Symmetric Key Cryptography – An Important Guide For 2021


There is an ever-present possibility of unauthorized access to all types of data in today’s cyberspace. The most vulnerable are financial and payment system data that may reveal Personal Identification Information (PII) or payment card details to consumers and clients. Symmetric Key Cryptography is essential to securing the PII and to alleviating the threats that payment transaction companies face every minute of every day. Symmetric Key Cryptography, also known as Symmetric Encryption, is when a secret key gets used for encryption and decryption purposes.

In this article, we will try to understand the concept of Symmetric Key Cryptography. Let’s start!

Table of Contents

  1. What is Symmetric Key Cryptography?
  2. How Does Symmetric Key Cryptography Work?
  3. What Are The Types of Symmetric Key Cryptography?
  4. What Are The Advantages & Disadvantages of Symmetric Key Cryptography?
  5. Example of Symmetric Key Cryptography
  6. What is Symmetric Key Cryptography Used For?

1) What is Symmetric Key Cryptography?

Symmetric key cryptography (or symmetric encryption) is a type of encryption technique in which the same key gets used for encrypting or decrypting data or messages. Such an encoding information method has been commonly used in recent years to promote classified contact between governments and the military. Today, symmetric key algorithms are generally used in different types of computer systems to improve data security.

2) How Does Symmetric Key Cryptography Work?

In symmetric key cryptography algorithms, the data gets transformed into a format that cannot be interpreted by someone who does not have the confidential key to decrypt it. Once the intended recipient who has the key gets the message, the algorithm reverses its behaviour such that the message is returned to its original and understandable form. The secret key used by the sender and the recipient may be a particular passcode or a random sequence of letters or numbers created by a secure random number generator (RNG).

3) What Are The Types of Symmetric Key Cryptography?

There are two types of symmetric key cryptography – 

  • Block algorithms: Set numbers of bits are encrypted in electronic data blocks using a particular secret key. As the data is encrypted, the system keeps the data in its memory as it waits for full blocks.
  • Stream algorithms: The data is encrypted as it streams rather than stored in the system’s memory.

4) What Are The Advantages & Disadvantages of Symmetric Key Cryptography?

Symmetric algorithms provide a high degree of protection, thus enabling fast encryption and decryption of messages. The relative simplicity of symmetrical structures is also a logistical benefit since they require less processing power than asymmetrical ones. Furthermore, symmetric encryption protection can improve if increased key lengths get provided. The difficulty to break encryption by a brutal force attack rises exponentially with each bit added to the length of a symmetric key.

Although symmetrical encryption provides several advantages, one of the main disadvantages of symmetric key cryptography is an inherent problem related to the key transmission used for encryption and decryption. If these keys get exchanged over an unsecured connection, malicious third parties may intercept them. If an unauthorized user gets access to a symmetrical key, the protection of all data encrypted using the key is affected. Many web-based protocols use symmetrical and asymmetric encryption to create safe links to solve this issue.

5) Example of Symmetric Key Cryptography

Some common symmetric key cryptography examples include the Advanced Encryption Standard (AES), the Data Encryption Standard (DES), along with IDEA, Blowfish, RC4 (Rivest Cipher 4), RC5 (Rivest Cipher 5), and RC6 (Rivest Cipher 6).

6) What is Symmetric Key Cryptography Used For?

Although symmetric key cryptography is an older encryption process, it is quicker and more reliable than asymmetric encryption, a network toll due to data size and extensive CPU usage performance problems. In general, symmetric encryption (as opposed to asymmetric) gets used to encrypt large quantities of the data, e.g., for the database’s encryption. The secret key will only be available for encryption or decryption in the case of a database. For example, it gets used for payment applications such as PII card purchases to avoid identity theft or fraudulent costs.


Symmetric key cryptography gets used widely for applications ranging from Internet traffic security and data protection on cloud servers thanks to its relative speed, flexibility, and security. Although often combined with asymmetric encryption, symmetrical encryption techniques remain a crucial element in modern Cyber Security to solve the problem of securely exchanging keys.
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