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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. 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.






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






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






4. Provides authentication and encryption of the payload.






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






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






7. DoS attacks are more probable with this mode.






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






9. '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.'






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






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


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






13. Uses IKE for key exchange.






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






15. The DES algorithm that performs 3 times sequentially.






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






17. '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.'






18. Common key size is 1024 bits.






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






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






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






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






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






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






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






26. Uses protocol number 50.






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






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






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






30. '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






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






32. 'MACs with hash algorithms -'






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






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






35. Used in IPsec for two discreet purposes:






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






37. Uses protocol number 51.






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






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






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


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






42. '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.'






43. '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.'






44. 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.






45. Does not provide payload encryption.






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






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






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






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