As the name suggest, symmetric encryption means that both the encryption and the decryption operations use the same key. The keys may be identical or may have some simple transformation (Kahate, 2013). In practice, they present a shared secret between two or more parties, and they can be used to maintain a given private information link. Therefore, both the sender and the receiver have access to the secret key.
Asymmetric encryption is also known as the public-key encryption. According to Kahate 2013, it is any cryptographic system that applies pairs of the keys, in this case, the public key, which is widely disseminated. On the other hand, there are the private keys only known by the owners. The keys accomplish two functions, the first one, authentication, where public keys are used to verify that the holder of private keys has sent the message. The other function is encryption, whereby it is only the owner of the private key paired can decrypt the encrypted message by the public key (Kahate, 2013).
Difference between Symmetric and Asymmetric Encryption
The first variance that makes the two different is that symmetric encryption uses one key to both encrypt and decrypt the information (Kahate, 2013). It means that the sender and the receiver share the same key. For example, when the sender sends an encrypted message, for the receiver to read the message, he/she uses the initial key that was used by the originator. On the other hand, asymmetric encryption uses one key to encrypt, and a different one to decrypt. Meaning, the function uses two different keys. For example, when there is a message with two keys that need to be converted, then, either key can be applied to encrypt the information. For instance, if there are key A and B, and the person had used key A to encrypt the message, the same key is applicable for decryption.
Another difference is that, for symmetric encryption, an extra channel is required to send the key to the receiver (Kahate, 2013). If at any case the two keys are sent together, there may emerge an interception. Contrary, asymmetric encryption does not require an extra channel to send the key to the message receiver. Lastly, symmetric uses fewer resources; hence it is faster, whereas the asymmetric technique uses more resources since encryption involves mathematical calculations.
In a typical situation, symmetric encryption method will enable a computer to function faster compared to the asymmetric procedure. The reason being, the asymmetric technique involves mathematical calculations; hence, the method is not efficient to the CPU functioning which determines the processing speed of a computer. The asymmetric key lengths are much longer, for example, 1024 and 2048 than the symmetric codes which are usually 128 and 256; therefore, it’s harder to crack an encrypted file with such long keys (Kahate, 2013). In fact, symmetric key encryption doesn’t require many CPU cycles, which make it have a higher processing speed.
It is true that asymmetric encryption requires high CPU processing powers and abilities; hence, its management cost must also be higher. Again, the technique uses two different keys, meaning, the available computer has to process the two separate algorithms to make the procedure effective. Primarily, asymmetric encryption seems stronger compared to the symmetric key, but the cost also differs. Therefore, it is advisable to use symmetric encryption to lower the management expenses and the general production cost of the firm.