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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. '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






2. 'MACs with hash algorithms -'






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






4. Benefits are that the preshared authentication can be based on ID versus IP address and the speed of the process.






5. '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






6. The DES algorithm that performs 3 times sequentially.






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






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






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






10. More CPU intensive






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






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






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






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






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






16. Verify whether the data has been altered.






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






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






19. 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.






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






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






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






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






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

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






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






27. 'Encryption - where Peer X uses Peer Y






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






29. DoS attacks are more probable with this mode.






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






31. Used in IPsec for two discreet purposes:






32. '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.'






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






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






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






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






37. Uses protocol number 51.






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






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






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






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






42. '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.'






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






44. '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.'






45. Common key size is 1024 bits.






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






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






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






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






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