Differences Between Symmetric vs Asymmetric Encryption


Choosing an encryption program to protect sensitive data may be a difficult challenge for someone who is not a techie or is largely new to cryptography, especially if they need to determine between symmetric and asymmetric encryption.

Questions are required to occur over their discrepancies, which are called the more stable method, and which one is more fitting for your needs. But before we answer all of these questions, we’d like to go back to the basics for the uninitiated, and begin by describing encryption.

An Overview: What Is Encryption?

The method of translating human-readable (plaintext) data into unintelligible ciphertext is encryption. This knowledge scrambling is the consequence of an algorithmic process that uses a cryptographic key. Simply put, cryptography takes the knowledge and makes it random so that it can not be accessed by someone who steals it until they have the key to translate it back into a legible shape.

If we want protection and to secure our data when at rest, in use, or in motion, the use of encryption is important. There are two key forms that we will compare in this article: symmetric encryption vs. asymmetric encryption.

Symmetric vs Asymmetric: The Two Types of Encryption and How They Work

Symmetric Encryption

The same key is used for both encrypting and decrypting messages in the case of symmetric encryption. Since the whole system relies on keeping a mutual secret of the key, which ensures that it has to be shared secretly with the receiver such that only they can use it to decode the code, it does not scale well.

Algorithms for symmetric encryption may use either block ciphers or stream ciphers. With block ciphers, a number of bits are encrypted as a single entity (in chunks). AES, for example, uses a 128-bit block size with options for three different key lengths: 128, 192, or 256 bits.

Symmetric encryption suffers from key depletion problems and it is likely that without careful protection of a key hierarchy or efficient key rotation, each use can leak information that an attacker can theoretically leverage to reconstruct the hidden key. While symmetric encryption has key management problems, it is faster and operates on network or CPU resources without a lot of overhead. It is therefore frequently used in tandem with asymmetric encryption, which we will discuss in the section below.

Key Takeaways of Symmetric Encryption

For encryption and decryption, there is a single shared key that is used.
Since the hidden key must not be lost or exchanged with unauthorized people, or else they will decipher the code, it does not scale very well.

Asymmetric Encryption

A pair of similar keys are used for asymmetric encryption: a public and a private key. The public key, which is open to everyone, is what is used before sending it to encrypt a plaintext message. You have to keep the private key to decrypt and read this message. The public and private keys are mathematically connected, but it is difficult to extract the private key.

The private key is only exchanged with the initiator of the key in asymmetric encryption (also known as public-key cryptography or public key encryption) because its confidentiality needs to be maintained.
The time needed is greater since asymmetric encryption is a more complex method than its symmetric equivalent. However, because the private key is not intended to be exchanged and is kept a secret, this form of encryption provides a higher degree of protection relative to symmetric encryption. It is a significantly more scalable approach as well.

Key Takeaways of Asymmetric Encryption

It requires the use of two keys that are mathematically related. For encrypting and decrypting the letter, the public key (the one that is known to all) and the private key (which is only known to you) are needed. It is not necessary to derive the private key from the public key.

The public key is used for someone to encrypt the messages they give to you, but one requires access to the private key to decode and interpret these messages.

What Is the Difference Between Symmetric and Asymmetric Encryption?

There are five key distinctions between symmetric and asymmetric encryption, which we’ll discuss shortly. Some of these variations are due to the kinds of keys used and others are related to how long it takes to compute the encryption methods.

So, when we’re talking about symmetric and asymmetric encryption, which is safer? Asymmetric encryption, although symmetric encryption is easier, is the safer one. In different ways, they are also very productive and, depending on the mission at hand, one or both can be used individually or together.

Hopefully, you now know the difference between symmetric and asymmetric encryption. A more in-depth distinction of symmetric and asymmetric encryption is given in the following table:

Differentiator Symmetric Key Encryption Asymmetric Key Encryption
1. Symmetric Key vs Asymmetric key Only one key (symmetric key) is used, and the same key is used to encrypt and decrypt the message. Two different cryptographic keys (asymmetric keys), called the public and the private keys, are used for encryption and decryption.
2. Complexity and Speed of Execution It’s a simple technique, and because of this, the encryption process can be carried out quickly. It’s a much more complicated process than symmetric key encryption, and the process is slower.
3. Length of Keys The length of the keys used is typically 128 or 256 bits, based on the security requirement. The length of the keys is much larger, e.g., the recommended RSA key size is 2048 bits or higher.
4. Usage It’s mostly used when large chunks of data need to be transferred. It’s used in smaller transactions, primarily to authenticate and establish a secure communication channel prior to the actual data transfer.
5. Security The secret key is shared. Consequently, the risk of compromise is higher. The private key is not shared, and the overall process is more secure as compared to symmetric encryption.
Examples of Algorithms Examples include RC4, AES, DES, 3DES, etc. Examples include RSA, Diffie-Hellman, ECC, etc.

Symmetric vs Asymmetric Encryption in the Context of the SSL/TLS Handshake

When we use the unreliable HTTP protocol to browse the web, data flows in an unencrypted format that can be quickly captured and hacked by someone on the network listening in. To encrypt the communication channel between the client (web browsers such as Chrome, Firefox, etc.) and the server you are trying to communicate with, SSL/TLS certificates are used to encode the communication channel so that you can browse HTTPS safely. The entire encryption process (which starts using asymmetric encryption and later moves to symmetric encryption for bulk transmission) takes only a few milliseconds, but there are a variety of steps involved in the handshake.

An encrypted communication channel is built between our client browser and the server hosting the site any time we connect to a website over HTTPS. When setting up a safe link, let’s get a quick rundown of where encryption comes into play:


Connection Negotiation

The SSL/TLS approach starts with the client hello message following the three-way handshake between the client and the server, which also communicates the supported cipher suites in addition to other parameters (e.g., RSA, Diffie-Hellman, etc.).

Centered on the highest encryption standard that is accepted by both the client and the server, the connection is negotiated.

Key Exchange

The client gets the server’s digital certificate containing its public key with a server hello message. It uses this key after checking the authenticity of the server certificate to produce a pre-master password. After encrypting it with the public key, the client sends it to the server with the pre-master key. The private key is used by the server to decrypt and obtain the same pre-master key. Both the client and the server independently determine the symmetric key based on the value of the pre-master secret key.

Change Cipher Spec

Both the server and the client send a shift cipher spec message to each other after calculating the symmetric key. This means that over a protected encrypted channel, the remaining communication involving some bulk data transmission will be achieved using symmetric keys (by implementing encryption standards such as AES).

In Summary: In the Debate of Symmetric vs Asymmetric Encryption, Both Are Important

We have only addressed all the key principles of symmetric and asymmetric encryption. “By now, queries should have been cleared up about “what is the difference between symmetric and asymmetric encryption” and “symmetric key vs asymmetric key. While they are both incredibly distinct based on various mathematical constructs, in multiple cases, they have both found their use. Symmetric encryption, for example, is used to secure file content or comes into the image of disk encryption, and digital signatures use asymmetric encryption.

In several other cases, aside from SSL, a variation of both of these methods is used. End-to-end encryption is utilized for networking apps such as Signal or WhatsApp, where asymmetric encryption is used to initialize the secure contact path, while the remainder of the contact uses symmetric encryption.

Melina Richardson is a Cyber Security Enthusiast, Security Blogger, Technical Editor, Certified Ethical Hacker, Author at Cybers Guards & w-se. Previously, he worked as a security news reporter.