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CCIE Sec Encryption Ipsec

Subjects : cisco, it-skills, ccie
Instructions:
  • Answer 50 questions in 15 minutes.
  • If you are not ready to take this test, you can study here.
  • Match each statement with the correct term.
  • Don't refresh. All questions and answers are randomly picked and ordered every time you load a test.

This is a study tool. The 3 wrong answers for each question are randomly chosen from answers to other questions. So, you might find at times the answers obvious, but you will see it re-enforces your understanding as you take the test each time.
1. IPSec SAs are negotiated and protected by the existing IPsec SA.






2. One of the most popular tunneling protocols is






3. Verify whether the data has been altered.






4. The sending device encrypts for a final time with another 56-bit key.






5. Has a trailer which identifies IPsec information and ESP integrity-check information.






6. Turns clear-text data into cipher text with an encryption algorithm. The receiving station decrypts the data from cipher text into clear text. The encryption key is a shared secret key that encrypts and decrypts messages.






7. Origin authentication validates the origin of a message upon receipt; this process is done during initial communications.






8. 'provides everything required to securely connect over a public media - such as the Internet.'






9. You use this encryption method by keeping one key private and giving the other key to anyone in the public Internet. It does not matter who has your public key; it is useless without the private key.






10. Negotiation of the ISAKMP policy by offering and acceptance of protection suites


11. Uses IKE for key exchange.






12. 'A 56-bit encryption algorithm - meaning the number of possible keys






13. 'MACs with hash algorithms -'






14. IPSEC Encryption is performed by


15. Where the original Layer 3 header and payload inside an IPsec packet is encapsulated. Tunnel mode does add overhead to each packet and uses some additional CPU resources.






16. 'requires that the sender and receiver have key pairs. By combining the sender






17. 'is a more secure version of MD5 - and hash-based message authentication codes (HMAC) provides further security with the inclusion of a key-based hash.'






18. A variable block- length and key-length cipher.






19. Drawback of this is that the hash is passed unencrypted and is susceptible to PSK crack attacks.






20. Message of arbitrary length is taken as input and produces as output a 128-bit fingerprint or message digest of the input.






21. 'algorithm encrypts and decrypts data three times with 3 different keys - effectively creating a 168-bit key.'






22. 'in most cases - this mode is preferred with certificates.'






23. Data integrity is the process of making sure data is not tampered with while it






24. It also provides protection for ISAKMP peer identities with encryption.






25. The DES algorithm that performs 3 times sequentially.






26. It uses UDP 500 and is defined by RFC 2409.






27. Uses protocol number 50.






28. 'can be achieved using one of three methods: preshared keys - encrypted nonces - or digital signatures.'






29. That authenticate data packets and ensure that data is not tampered with or modified.






30. 'key exchange is vulnerable to a man-in-the-middle attack. You can rectify this problem by allowing the two parties to authenticate themselves to each other with a shared secret key - digital signatures - or public-key certificates.'






31. 'It is not used for encryption or digital signatures; it is used to obtain a shared secret






32. This mode does not support identity protection or protection against clogging attacks and spoofing.






33. You check it by hashing data and appending the hash value to the data as you send it across the network to a peer.






34. The receiving device then encrypts the data with the second key.






35. 'has a Next Protocol field which identifies the next Layer 4 transport protocol in use - TCP or UDP'






36. Provides authentication and encryption of the payload.






37. IPSEC performs this function by using a sequence field in the IPsec header combined with integrity checks.






38. 'Created by NIST in 1994 - is the algorithm used for digital signatures but not for encryption.'






39. Takes variable-length clear-text data to produce fixed-length hashed data that is unreadable.






40. Used for integrity checks on peer and data sent by peer and for authentication checks.






41. Main disadvantage of asymmetric algorithms is that they are slow.






42. The protocol of choice for key management and establishing security associations between peers on the Internet.






43. Benefits are that the preshared authentication can be based on ID versus IP address and the speed of the process.






44. 'establishes ISAKMP SA in three messages -because it negotiates a ISAKMP policy and a DJ nonce exchange together.'






45. Act of encapsulating a packet within another packet.






46. 'Encryption - where Peer X uses Peer Y






47. Hybrid protocol that defines the mechanism to derive authenticated keying material and negotiation of security associations (SA).






48. IPsec implements using a shim header between L2 and L3






49. 'Message digest algorithms have a drawback whereby a hacker (man in the middle) can intercept a message containing the packet and hash values - then re-create and transmit a modified packet with the same calculated hash to the target destination.'






50. A