Test your basic knowledge |

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. IPsec implements using a shim header between L2 and L3






2. '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






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






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






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






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






7. '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.'






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






9. Uses protocol number 50.






10. Act of encapsulating a packet within another packet.






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






12. 'Encryption - where Peer X uses Peer Y






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






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






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






16. Uses IKE for key exchange.






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






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






19. A






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






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






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






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






24. DoS attacks are more probable with this mode.






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






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






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






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






29. Common key size is 1024 bits.






30. 'including Internet Security Association and Key Management Protocol (ISAKMP) - Secure Key Exchange Mechanism for the Internet (SKEME) - and Oakley.'






31. Used in IPsec for two discreet purposes:






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


33. '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.'






34. IPSEC Encryption is performed by


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






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






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


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






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






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






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






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






44. '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.'






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






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






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






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






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






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