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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. Does not provide payload encryption.






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






3. DoS attacks are more probable with this mode.






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






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






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






7. 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.






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






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






10. The DES algorithm that performs 3 times sequentially.






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


12. 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.






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






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






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






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






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. Integrity checks are done


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






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






21. Uses IKE for key exchange.






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






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






24. '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.'






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






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






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






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






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






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






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






33. 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.






34. Used in IPsec for two discreet purposes:






35. '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.'






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






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






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






39. IPSEC Encryption is performed by


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






41. Uses protocol number 51.






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






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






44. '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.'






45. A






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






47. Key exchange for IPSEC






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






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






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