Types of Encryption
In symmetric encryption single key is used by both sender and receiver for encryption and decryption. Therefore both the parties have to exchange the key and thus trust issues arise here a lot. Some of symmetric key algorithms are DES(Data Encryption Standard), Triple DES, AES(Advanced Encryption Standard).
Suppose there are two-person A and B, A wants to send his/her data from an insecure network to B. A will encrypt the data with key and B will have to decrypt it with the same key.
In asymmetric encryption pair of the key are used, one is called public key and the other is private key. The private key is kept secret by the owner and the public key is shared. Data encrypted with the recipient's public key can only be decrypted by the corresponding private key.
Suppose A wants to send data to B, so A must have B's public key to encrypt the data then B decrypt the same with his/her corresponding private key.