Explanation/Reference:
Explanation:
SSL uses asymmetric encryption to securely share a key. That key is then used for symmetric encryption to encrypt the data.
IPsec and SSL use asymmetric encryption to establish the encryption protocol when the session starts and then to securely exchange a private key used during the session. This private key is similar to the single secret key used in symmetric encryption.
Asymmetric encryption uses a key pair -- both a public and a private one -- for encryption. The sender uses the receiver's public key to encrypt the data and the receiver uses their private key to decrypt it. The transmission is secure because the recipient always has the private key in their possession and never exposes it by sending it over a public connection, such as the Internet.
There is a catch to using asymmetric encryption. It runs about 1,000 times slower than symmetric encryption and eats up just as much processing power, straining already overburdened servers. That means asymmetric encryption is only used (by IPsec and SSL) to create an initial and secure encrypted connection to exchange a private key. Then, that key is used to create a shared secret, or session key, that is only good during the session when the two hosts are connected.
Incorrect Answers:
A: SSL uses both symmetric and asymmetric encryption, not just symmetric encryption.
C: SSL does not use only public key encryption; shared key (symmetric) encryption is also used.
D: SSL does not use private key encryption. Initially, encryption is performed using public keys and decryption is performed using private keys (asymmetric). Then both encryption and decryption are performed using a shared key (symmetric).
References:
http://searchsecurity.techtarget.com/answer/How-IPsec-and-SSL-TLS-use-symmetric-and-asymmetric- encryption