Encryption is the technique used to obscure messages and information, and ciphers are the algorithms used to perform the encryption and decryption.
The two types of cryptographic methods are
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Private key cryptography (also known as symmetric key algorithms)
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Public key cryptography (also known as asymmetric key algorithms)
In private key cryptography, the sender and receiver have a shared key, and both the sender and receiver use the same key for encryption and decryption. Symmetric key algorithms use ciphers such as RC4, DES, and AES.
In public key cryptography, a key pair consisting of a public key and a private key is used. The public key enables any entity to exchange encrypted data with the holder of the private key. The private key enables the holder to prove his identity and encrypt data, which can be decrypted by anyone having the public key.
The public key enables any sender to perform encryption, while the private key is used by the receiver to decrypt the message. Asymmetric key algorithms use ciphers such as RSA.
Public key cryptography is generally slower than private key cryptography; therefore, cryptographic protocols such as Secure Sockets Layer (SSL), also known as Transport Layer Security (TLS), use public key cryptography to exchange session keys. These session keys, which are temporary symmetric keys, are then used to exchange encrypted data during the session of limited duration. The use of session keys (symmetric keys) improves the speed of encrypted data exchanges.
