ccna automation

ccna automation. Alice runs the DH algorithm a second time using Bob's public value (Yb) as the new base. Bob also runs the DH algorithm a second time using Alice's public value (Ya) as the new base.The result is that both Alice and Bob get the same result (Z). This new value is a shared cipher between Alice and Bob and can be used by the encryption algorithm as a shared key between Alice and Bob. Anyone listening to the channel cannot compute the secret value, since the only known values are g, p, Ya and Yb,and at least one secret value is needed to compute the shared key. Unless an attacker can compute a discrete algorithm of the above equation to recover xa or Xb,they cannot obtain the shared key. Although DH is used with symmetric algorithms to create shared keys, it is important to remember that it is actually an asymmetric algorithm.7.4 Public Key Cryptography7.4.1 Symmetric and Asymmetric Encryption7.4. l1 Asymmetric Key AlgorithmsAsymmetric algorithms, sometimes called public-key algorithms, are designed so that the key used for encryption is different from the key used for decryption. The decryption key cannot be computed from the encryption key within any acceptable time, and vice versa.In the case of Alice and Bob, they do not exchange pre-shared keys before communicating. Instead, they each have their own padlock and corresponding key. Similarly, asymmetric algorithms exchange confidential messages and do not require the use of any shared password before the exchange begins.There are four protocols that use asymmetric key algorithms.Internet Key Exchange (IKE), a fundamental component of IPSec VPNs.