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






2. Act of encapsulating a packet within another packet.






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






4. Uses IKE for key exchange.






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






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






7. Common key size is 1024 bits.






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






9. Key exchange for IPSEC






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






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






12. '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.'






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






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






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






18. Uses protocol number 51.






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






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






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






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






23. '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.'






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






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






26. 'establishes ISAKMP SA in three messages -because it negotiates a ISAKMP policy and a DJ nonce exchange together.'






27. 'MACs with hash algorithms -'






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






29. One of the most popular tunneling protocols is






30. 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.






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






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






33. This mode does not support identity protection or protection against clogging attacks and spoofing.






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






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 tunnels data through IP using one of two protocols?






37. '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.'






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






39. '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.'






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






41. 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.






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






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






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






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






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






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






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






49. 'Encryption - where Peer X uses Peer Y






50. 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.