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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. Uses protocol number 51.






2. '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.'






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






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






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






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






7. Does not provide payload encryption.






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






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


10. Can be implemented efficiently on a wide range of processors and in hardware.






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






12. More CPU intensive






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






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






15. 'group 2 identifies a 1024-bit key - group 2 is more secure - but slower to execute.'






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






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






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






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






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


21. 'The messages are authenticated - and the mechanisms that provide such integrity checks based on a secret key are usually called'






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






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






24. '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.'






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






26. 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.






27. Integrity checks are done


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






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






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






31. '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.'






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






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






34. '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.'






35. Provides authentication and encryption of the payload.






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






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






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






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






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






41. Act of encapsulating a packet within another packet.






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


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






44. Used in IPsec for two discreet purposes:






45. ' is defined in RFC 3174. has as output a 160-bit value -'






46. The DES algorithm that performs 3 times sequentially.






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






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






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






50. Is a two-phase protocol: The first phase establishes a secure authenticated channel and the second phase is where SAs are negotiated on behalf of the IPsec services.