What is a Symmetric Encryption?

In this modern world where everyone is posting and consuming a lot of information from the internet, it is also an open window for attackers to get access to someone's personal data and tamper with it or make use of it for the loss of the owner, thus it becomes quite dangerous to let the data travel over the internet in it original format. This can be done using encryption of data that converts the data into some bogus information which will not be useful for anyone who doesn't know how we gain back the original text. In this article how we can make use of Symmetric Encryption to convert plain text into cipher text and then decrypt this cipher text back to the plain text.

What is Symmetric Encryption?

When the plain text is encrypted and decrypted using the same key, it is known as symmetric encryption. It is also known as "shared-key" or "private-key" encryption. It ensures confidentiality by ensuring only authorized parties with the key can access the original data.

The key is a piece of a shared secret between the two parties involved hence it is 'shared-key' and is kept secret, hence the name 'private-key' is justified.

How does Symmetric Encryption Work?

From key generation to decryption, multiple steps are involved when symmetric encryption is applied. These are the steps involved in sharing a message securely over the network using the symmetric encryption technique.

1. Key Generation:

The first step involves selecting a private key. A secure key is generated using algorithms like PBKDF2 (Password-Based Key Derivation Function 2) or hardware random number generators. This key must be securely shared or transferred over the network for future use.

Example: A 256-bit AES key: 3A7F2B4E... (32-byte hexadecimal string).

2. Encryption:

In this step, the original message (plain text) is transformed into unreadable text (ciphertext) ,and the plaintext is processed in blocks or streams using an encryption algorithm and the secret key.

Example: AES-256 in CBC (Cipher Block Chaining) mode encrypts a 128-bit block of plaintext with the key and an initialization vector (IV) to produce ciphertext.

3. Transfer of Cipher text:

The encrypted message (ciphertext) is then sent over the network. Even if intercepted, it remains unreadable to the attacker unless they have access to the shared secret key and the algorithm used for encryption.

4. Decryption:

In the final step, the recipient uses the same secret key and a reverse encryption algorithm to convert the cipher text back into the original message (plain text).

Advantages of Symmetric Encryption

Symmetric encryption has been proven to be a fast, simple and efficient method of securing communication. Some of the key advantages of symmetric encryption include:

• Speed: Symmetric encryption algorithms are typically faster and less computationally demanding than asymmetric encryption, making them ideal for encrypting large volumes of data efficiently.
• Simplicity: With symmetric encryption, a single key is used for both encryption and decryption, simplifying key management particularly in scenarios where key sharing is not a significant concern.
• Bandwidth Efficiency: Encrypted data using symmetric algorithms tends to be smaller in size, which helps reduce bandwidth usage when transmitting encrypted information.

Challenges of Symmetric Encryption

While symmetric encryption is widely valued for its speed and efficiency, it also comes with several challenges regarding the storing and sharing of the key, here are the following causes:

• Key Sharing Security: The primary challenge lies in securely sharing the secret key. If the key is compromised, the entire communication becomes vulnerable. So use asymmetric encryption (e.g., RSA) for initial key exchange (hybrid systems)
• Key Storage: Safely storing the secret key is another significant concern, as unauthorized access to the key can compromise the security of the encrypted data. So use the Hardware Security Modules (HSMs) for tamper-resistant storage and for cloud use Cloud-based Key Management Services (KMS) like AWS KMS or Azure Key Vault.
• Scalability: As the number of users grows, the complexity of securely managing and sharing secret keys increases exponentially, making it more difficult to maintain a robust security framework, so implement hierarchical key structures or automated rotation policies.

Application of Symmetric Encryption

Due to its speed and efficiency, Symmetric encryption is widely used for securing communications. Some of the most common use-cases of symmetric encryption includes:

• File and Disk Encryption: Symmetric encryption is the preferred choice for securing files, databases, and entire drives due to its robust performance and simplicity.
• Bulk Data Encryption: For encrypting large volumes of data, symmetric encryption is the go-to method because of its faster processing time compared to asymmetric encryption.
• Hybrid Algorithms: While asymmetric encryption is crucial for securing keys and verifying identities, it is not ideal for data encryption. Hybrid systems combine the strengths of both, using asymmetric encryption for key exchange and symmetric encryption for the actual data encryption.

Types of Symmetric Encryption Algorithms

Symmetric encryption has various types, depending on their features, strengths and effectiveness. Some of the most popular symmetric encryption algorithms includes:

Conclusion

Symmetric encryption is an effective solution to secure information, as it turns the original data into unreadable data that can only be read by someone with the correct key. This helps protect the data from unauthorized access during transmission.

Symmetric encryption is fast, simple, and efficient, but it does have some challenges. The biggest issue is securely sharing and storing the secret key. As the number of users grows, managing these keys can get more complicated. However, symmetric encryption is widely used for securing files, encrypting large amounts of data, and in hybrid systems that combine both symmetric and asymmetric encryption for added security.

Popular symmetric encryption algorithms like AES, DES, and Triple DES each offer different levels of security. Understanding how these encryption methods work and where they are applied is crucial for ensuring the safety of sensitive data.

Also Read: What is Asymmetric Encryption?