ccna apply

ccna apply.Network layer protocols, such as IPSec protocol clusters, provide network layer confidentiality.Protocols such as Secure Sockets Layer (SSL) or Transport Layer Security (TLS) provide session layer confidentiality.Secure email, secure database sessions (OracleSQL*net), and secure messaging mechanisms (LotusNotes sessions) provide application layer confidentiality.There are two ways of securing data when using various encryption methods. The first way is to protect the algorithm. If the security of an encryption system is based on the secrecy of the algorithm itself, the algorithm code must be tightly protected. If the algorithm is compromised, all interested parties must change the algorithm. The second way is to protect the key. For modern cryptography, all algorithms are public and the confidentiality of the data is ensured by a cryptographic key. An encryption key is a sequence of bits that are to be encrypted and entered into an encryption algorithm together with the data.There are two basic classes of encryption algorithms used to protect keys: symmetric and asymmetric. They differ in their use of keys. Symmetric encryption uses the same key (sometimes called a secret key) to encrypt and decrypt data. This key must be pre-shared, and the sender and receiver already know the pre-shared key before the encrypted communication begins. Since both parties protect a shared secret, the encryption algorithm used can have a shorter key length. Shorter key length means faster execution. -. In general, symmetric algorithms are much less computationally intensive than asymmetric algorithms.Asymmetric encryption algorithms use different keys to encrypt and decrypt data. No pre-shared key is required to exchange secure messages. Since there is no shared secret between the two parties, a very long cipher length must be used to thwart an attacker. This type of algorithm is resource intensive and slow to execute. In practice, asymmetric algorithms are typically hundreds to thousands of times slower than symmetric algorithms.7.3 Confidentiality 1997.3.1.2 Symmetric and Asymmetric EncryptionTo help understand the differences between the two types of algorithms, consider an example in which Alice and Bob live in different places and want to exchange secret messages through the mail system. In this example, Alice wants to send Bob a . secret message.Symmetric Algorithm