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






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






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






4. '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






5. Uses IKE for key exchange.






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






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






8. 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.






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






10. '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.'






11. 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.






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






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






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






15. Used in government installs and was created to work with the SHA-1 hash algorithm.






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






17. Act of encapsulating a packet within another packet.






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






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






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






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






22. 'Encryption - where Peer X uses Peer Y






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






24. IPSEC Encryption is performed by


25. '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.'






26. Provides authentication and encryption of the payload.






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






28. A






29. Common key size is 1024 bits.






30. '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






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






32. 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.






33. More CPU intensive






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






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






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






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






38. Verify whether the data has been altered.






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






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






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






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






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






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






45. Uses protocol number 51.






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






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






48. Integrity checks are done


49. '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.'






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