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






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






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






4. A






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






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






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






8. More CPU intensive






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






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






11. Used in IPsec for two discreet purposes:






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


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






14. '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.'






15. Key exchange for IPSEC






16. 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.






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






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






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






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






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






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






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






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






25. Uses IKE for key exchange.






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






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






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






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






30. '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.'






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






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






33. Provide authentication in Internet Key Exchange (IKE) Phase 2.






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






35. Common key size is 1024 bits.






36. Provides authentication and encryption of the payload.






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


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


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






40. IPSEC Encryption is performed by


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






42. 'MACs with hash algorithms -'






43. '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






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






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






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






47. '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.'






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






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






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