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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. '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.'






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






3. Uses protocol number 51.






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






5. 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.






6. '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.'






7. '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.'






8. '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






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






10. 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.






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


12. The DES algorithm that performs 3 times sequentially.






13. Uses IKE for key exchange.






14. Does not provide payload encryption.






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


16. Provides authentication and encryption of the payload.






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






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






19. Verify whether the data has been altered.






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






21. '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.'






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






23. Integrity checks are done


24. Key exchange for IPSEC






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






26. '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.'






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






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






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






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






31. Used in IPsec for two discreet purposes:






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






33. DoS attacks are more probable with this mode.






34. 'can be achieved using one of three methods: preshared keys - encrypted nonces - or digital signatures.'






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






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






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






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






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






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






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






42. 'MACs with hash algorithms -'






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






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






45. 'Encryption - where Peer X uses Peer Y






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






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






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






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






50. Act of encapsulating a packet within another packet.