Cisco Certified Network Associate (CCNA) Practice Exam

Which IKE remote peer authentication method is identified as the most secure?

1. Preshared Keys

2. Public Key Signature

3. Challenge-Response

4. Secure Token Authentication

The correct answer is: Public Key Signature

Public Key Signature is identified as the most secure IKE remote peer authentication method because it utilizes asymmetric cryptography, which relies on a pair of keys: a public key and a private key. This method enhances security by allowing the parties involved to verify each other's identities without sharing secret keys over the network, which could potentially be intercepted. In this approach, each party generates a public/private key pair and shares their public key with the other. When establishing a secure connection, one party can sign a message with their private key, and the other party uses the corresponding public key to verify the signature, ensuring both authenticity and integrity. This strong cryptographic foundation makes it significantly harder for attackers to impersonate legitimate users or to gain access to sensitive data. Other methods, such as preshared keys, involve sharing a secret key in advance, which can be less secure if the key is not managed properly. Challenge-Response is better than preshared keys but generally still does not offer the same level of security against impersonation or replay attacks. Secure Token Authentication, while improving on simple challenge-response methods, also lacks the cryptographic robustness that public key signatures provide. Thus, Public Key Signature stands out as the most secure authentication method in IKE.