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






2. '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.'






3. A






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






5. ID exchange and authentication of D-H key by using the reply to the received nonce or string of bits


6. Negotiation of a shared secret key for encryption of the IKE session using the D-H algorithm


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






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


9. 'often called public-key algorithms - do not rely on a randomly generated shared encryption key; instead - they create two static keys. These static keys are completely different - but mathematically bound to each other; what one key encrypts - the o






10. Provides authentication and encryption of the payload.






11. 'Developed in 1977 by Ronald Rivest - Adi Shamir - and Leonard Adleman (therefore - RSA).'






12. IPSec SAs are negotiated and protected by the existing IPsec SA.






13. 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.






14. 'Finally - the receiving devices decrypt the data with the first key.'






15. Uses the D-H algorithm to come to agreement over a public network.






16. 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.






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






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






19. '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.'






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






21. Uses protocol number 51.






22. Uses protocol number 50.






23. No additional Layer 3 header is created. The original Layer 3 header is used.






24. 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.






25. 'When using the hash-based key function -'






26. 'group 1 identifies a 768-bit key - group 1 is faster to execute - but it is less secure -'






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






28. '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.'






29. 'Digital signatures. Peer X encrypts a hash value with his private key and then sends the data to Peer Y. Peer Y obtains Peer X






30. 'defines the mode of communication - creation - and management of security associations.'






31. 'The sending device decrypts the data with the second key - which is also 56 bits in length.'






32. 'produces a 160-bit hash output - which makes it more difficult to decipher.'






33. 'group 5 identifies a 1536-bit key - provides for highest security but is the slowest of all groups.'






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






35. Integrity checks are done


36. Used in IPsec for two discreet purposes:






37. IPSEC tunnels data through IP using one of two protocols?






38. More CPU intensive






39. Key exchange for IPSEC






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






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






42. DoS attacks are more probable with this mode.






43. 'Three keys encrypt the data - which results in a 168-bit encryption key. The sending device encrypts the data with the first 56-bit key.'






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






45. 'Encryption - where Peer X uses Peer Y






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






47. The receiving device decrypts the data with the third key.






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






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






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