Symmetric and Asymmetric encryption

Alessandro Mirani

Encryption is the process of converting plaintext into ciphertext to secure the information being transmitted. There are two main types of encryption: symmetric and asymmetric encryption.

Differences between symmetric and asymmetric encryption?

Symmetric encryption, also known as private key encryption, uses one key to both encrypt and decrypt data. This makes symmetric encryption faster than asymmetric encryption because only one key is needed. However, the same key must be shared between both communicators, so trust is required.

On the other hand, asymmetric encryption is more secure. It uses two keys: a public and private key. The two keys work together, meaning one encrypts and the other decrypts. This means that anyone can encrypt a message using the public key, but only the intended recipient can decrypt it using the private key.

Asymmetric encryption provides a more secure method of communication, as the private key is never shared or transmitted. For this reason, asymmetric encryption is often used today since it is more secure against malicious attacks such as brute force or Man in the Middle (MITM) attacks.

Types of Asymmetric Encryption

Not all the Asymmetric Encryption protocols are made the same. Here follows a comparison of the most popular Asymmetric Encryption techniques:

Here’s a brief comparison of some popular types of asymmetric encryption:

  1. RSA (Rivest-Shamir-Adleman) – RSA is one of the oldest and most widely used asymmetric encryption algorithms. It was invented in 1977 and is based on the difficulty of factoring large numbers. RSA keys can be generated in various sizes, with longer keys offering higher security. However, longer keys also require more processing power to encrypt and decrypt data.
  2. Elliptic Curve Cryptography (ECC) – ECC is a newer type of asymmetric encryption that uses elliptic curves instead of large prime numbers for key generation. ECC keys are shorter than RSA keys and offer the same level of security with smaller key sizes, making it more efficient in terms of computational power and storage space.
  3. DSA (Digital Signature Algorithm) – DSA is another popular asymmetric encryption algorithm that is commonly used for digital signatures. It was developed by the US National Institute of Standards and Technology (NIST) and is based on the difficulty of computing discrete logarithms in a finite field. DSA keys are typically shorter than RSA keys, but they are generally slower and less commonly used than RSA or ECC.
  4. Diffie-Hellman – Diffie-Hellman is a key exchange algorithm used for generating shared secret keys between two parties. It is not an encryption algorithm, but rather a way for two parties to agree on a shared key that can be used for symmetric encryption. Diffie-Hellman is commonly used in conjunction with other asymmetric encryption algorithms, such as RSA or ECC, to establish a secure communication channel.

The choice of asymmetric encryption algorithm depends on the specific security requirements of the application, as well as the computational resources available to the user. RSA is still the most widely used algorithm due to its long-standing history and strong security, but ECC is gaining popularity due to its efficiency and smaller key sizes. DSA and Diffie-Hellman are less commonly used, but they can be useful in certain applications such as digital signatures and key exchange.

How to choose between symmetric and asymmetric encryption

Asymmetric Encryption, as said before, can be considered more secure overall. However, that doesn’t mean that it should be your default choice. Here follows a few guidelines to keep in mind when choosing between asymmetric and symmetric cryptography for data encryption:

  • Performance Needs: Symmetric cryptography is faster and more efficient than asymmetric cryptography. As such, it is more appropriate for scenarios where high performance is required, such as encrypting large amounts of data.
  • Key Management: Asymmetric cryptography requires the management of two keys, which can be more complex and time-consuming. Symmetric cryptography requires the management of only one key.
  • Compatibility: Asymmetric cryptography is not compatible with all systems, whereas symmetric cryptography is generally more widely supported and can be implemented on more applications due to lesser complexity.

You should consider their specific security and performance needs, as well as their key management and compatibility requirements when choosing between asymmetric and symmetric cryptography. The fact that Symmetric Encryption is less complex than Asymmetric does not mean it doesn’t satisfy your business or regulatory needs.


We had an overview of symmetric and asymmetric cryptography for data encryption. Asymmetric cryptography provides better security but is slower and more complex to manage, while symmetric cryptography is faster and simpler but less secure. You should consider these elements when choosing between the two of them.

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