The main differentiating factor between symmetric and asymmetric cryptography is the number of keys used. While symmetric cryptography uses a single key for encryption and decryption, its asymmetric counterpart uses two. A public and a private key get used for encrypting and decrypting, respectively.
And based on that, you can spot differences in encryption speed and security. For example, symmetric encryption is less secure due to using a single key only. On the contrary, the asymmetric method is a lot safer. Nevertheless, the former requires less time for encryption, leaving the latter behind in speed.
Need to Know the Important Cryptography Terms
Before we dive deep into the symmetric vs asymmetric cryptography battle, a glance at the terms below will come in handy.
Keys are like these secret passwords that you can use to encrypt or decrypt a piece of information. For example, in symmetric encryption, if you encrypt something using a particular key, someone else won’t be able to decrypt it without that same key.
The method of locking up data by means of cryptography is known as encryption. Data locked during the process is said to be encrypted and cannot later be viewed or accessed without decryption.
It is the process we use to access some encrypted information. Therefore, if encryption is the locking mechanism, decryption resembles the unlocking of the same piece of info.
This defines the science of concealing something from a group of snoopers. Although the definition seems in line with that of encryption, steganography makes it look like there’s no hidden information, to begin with. So, it is somewhat safer.
An Overview of Symmetric and Asymmetric Key Cryptography
Here’s a quick overview of the basics, along with the pros and cons of each cryptography technique.
1. Symmetric Key Encryption
It is a process where a single cryptographic key gets used while both encrypting and decrypting a piece of information. And that makes symmetric key encryption the simplest method of altering data for protection. Therefore, it is the most widely used technique despite having originated back in the days of the Roman Empire.
The key used in symmetric encryption can be either a number, a word, or a string, which gets blended with plain text. Both the sender and the receiver should know the key in order for the encryption to work.
Advantages of Symmetric Encryption
Symmetric encryption will have an edge over the competition, thanks to its strong sides as mentioned below.
Symmetric encryption algorithms like the AES offer top-notch security. Cracking AES-encrypted data with a typical brute-force approach would require over a billion years.
The length of the keys used in symmetric encryption is pretty short. That, paired with the relatively simple techniques, allows much faster encryptions. So, it can get incorporated into real-time message-passing applications.
Due to its excellent security and speed advantages, symmetric encryption has been the industry standard for quite some time. As a result, adopting this technique will not bring problems with acceptance.
Disadvantages of Symmetric Encryption
No encryption technique is void of disadvantages that you may have to make peace with.
a. Single Cryptographic Key
This one might come as a surprise since a single key allows for convenient encryption. But as that key needs to get exchanged between the sender and receiver, it can get exposed during transmission. Also, securely storing a single key is a challenge of its own.
b. Relatively Less Secure
When compared, symmetric cryptography might turn out less secure than its asymmetric counterpart. However, the better safety of asymmetric cryptography comes at the cost of a slow encryption rate.
2. Asymmetric Key Encryption
Asymmetric key encryption, aka public key encryption, uses two keys instead of one for encrypting plain text. The two keys, one public and one private, have a mathematical link. And so both are required for the encryption to work flawlessly.
Unlike the public key, the private key is known to nobody else other than the sender and recipient. That keeps intruders from decrypting and accessing the contents of a message.
Also, this type of encryption does not need an exchange of the same key. Yes, the public key gets shared, but it has nothing to do with the decryption process.
Like symmetric cryptography, the core methodology here is to convert plaintext into ciphertext and vice versa, the only difference being the number of keys.
Advantages of Asymmetric Encryption
Despite being relatively new in the game, symmetric encryption has quite a few perks.
a. No Key Distribution Required
With asymmetric cryptography, the public keys get shared over public-key servers as they don’t play a part in decrypting the original message. As a result, there’s no need to provide secure distribution channels for the keys.
b. Private Keys Don’t Require an Exchange
The private keys in asymmetric encryption stay secure on both ends of the message transmission. Hence, the risk of exposing private keys over a potentially compromised transmission medium gets omitted. That, in turn, offers excellent security and integrity of the encrypted information.
c. Better Authentication
Since the unique private keys are only accessible to the senders, they can use them as a form of verification. Receivers can then look for the digital sign to make sure it arrived from an authentic source and not a scammer on the way.
Disadvantages of Asymmetric Encryption
Below are a couple of sectors that force asymmetric encryption to fall behind in the race.
a. Slow Encryption
Since asymmetric encryption uses longer cryptographic keys, calculations tend to be more time-consuming. The difference becomes more apparent when compared side by side with symmetric encryption.
b. Complex Implementation
As mentioned earlier, asymmetric cryptography uses lengthy keys for better security. But that has its drawbacks, especially in terms of implementation difficulty. The exceptionally long keys make it hard to implement on a more commercial level.
What Is the Difference Between Symmetric and Asymmetric Cryptography
The key differences are as follows, separating the two and making it clear which to use where.
|Area of Difference
|Number of Keys
|Only a single key is necessary for both encryption and decryption.
|It needs two separate keys for encryption and decryption, one public key and one private key
|Size of Cipher Text
|Equivalent to or smaller than the text to be encrypted.
|Usually larger than the original plaintext.
|Used when a large chunk of data is to be transferred.
|Used when transmitting small but significant data.
|Relatively slower compared to symmetric encryption.
|The use of a single key makes it less secure.
|The involvement of two keys means more security.
|Level of Service
|Provides confidentiality at most.
|Provides both authenticity and non-repudiation
|Low resource utilization is required.
|Required high utilization of computational resources.
|128 to 256 bits.
|2048 bits or lengthier.
|Efficient in handling large chunks of data.
|Less efficient as compared to symmetric cryptography.
|AES, RC4, DES, 3DES
|RSA, ECC, Diffie-Hellman, DSA
Regardless of having a safer two-key approach, asymmetric cryptography is yet to become mainstream. The reason is the use of extraordinarily long cryptographic keys that make it slower and hard to implement than symmetric cryptography. But if you have the infrastructure, it is worth giving a shot.