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






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






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


4. '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.'






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






6. Key exchange for IPSEC






7. Negotiation of a shared secret key for encryption of the IKE session using the D-H algorithm


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






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






10. 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.






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






12. IPSEC Encryption is performed by


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






14. Does not provide payload encryption.






15. '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






16. DoS attacks are more probable with this mode.






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






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






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






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






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






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






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


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






25. Takes variable-length clear-text data to produce fixed-length hashed data that is unreadable.






26. '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






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






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






29. 'Encryption - where Peer X uses Peer Y






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






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






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






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






34. '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.'






35. Provides authentication and encryption of the payload.






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






37. One of the most popular tunneling protocols is






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






39. '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.'






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






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






42. 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.






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






44. Integrity checks are done


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






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






47. 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.






48. Uses protocol number 51.






49. Verify whether the data has been altered.






50. '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.'