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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. 'DSA is roughly the same speed as RSA when creating signatures - but 10 to 40 times slower when verifying signatures. Because verification happens more frequently than creation - this issue is worth noting when deploying DSA in any environment.'






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






3. Provide authentication in Internet Key Exchange (IKE) Phase 2.






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

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5. 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.






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

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






8. 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.






9. IPSEC Encryption is performed by

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






11. 'Encryption - where Peer X uses Peer Y






12. Uses protocol number 51.






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






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






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






16. '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.'






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






18. DoS attacks are more probable with this mode.






19. More CPU intensive






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






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






22. '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






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






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






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






26. '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.'






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






28. Does not provide payload encryption.






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






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






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






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






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






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






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






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






37. Verify whether the data has been altered.






38. Act of encapsulating a packet within another packet.






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






40. Provides authentication and encryption of the payload.






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






42. '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.'






43. Uses IKE for key exchange.






44. 'is a block-cipher algorithm - which means that it performs operations on fixed-length data streams of 64-bit blocks. The key ostensibly consists of 64 bits; however - only 56 are actually used by the algorithm.'






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






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






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






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






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






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