Symmetric versus asymmetric encryption The most widely used symmetric algorithm is AES-128, AES-192, and AES-256. The main disadvantage of the symmetric key encryption is that all parties involved have to exchange the key used to encrypt the data before they can decrypt it. With asymmetric keys the server generates a pair of keys: public and private. The private key is kept safe but the public key can be sent in the clear to the client. [Read More]