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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. Main mode establishes ISAKMP security association in six messages and performs authenticated D-H exchange.






2. Uses protocol number 51.






3. '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.'






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






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






6. '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.'






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






8. Integrity checks are done


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


10. Uses IKE for key exchange.






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






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






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






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






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






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






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






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






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






20. Does not provide payload encryption.






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






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






23. '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






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






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






26. Uses protocol number 50.






27. 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.






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






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






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






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






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






33. '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






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






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






36. Used in IPsec for two discreet purposes:






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






38. IPSEC Encryption is performed by


39. Act of encapsulating a packet within another packet.






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






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






42. 'key lengths are 128 - 192 - or 256 bits to encrypt blocks of equal length.'






43. Invented by Ron Rivest of RSA Security (RFC 1321).






44. RFC 2631 on the workings of the key generation/exchange process.






45. More CPU intensive






46. Provides authentication and encryption of the payload.






47. Key exchange for IPSEC






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






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






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