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






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






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






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






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






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






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






8. Common key size is 1024 bits.






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






10. A






11. '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.'






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






13. 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.






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






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






16. 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.






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






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






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






20. Act of encapsulating a packet within another packet.






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






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

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






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






25. Uses protocol number 51.






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






27. Provides authentication and encryption of the payload.






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






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






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






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






32. Uses IKE for key exchange.






33. Does not provide payload encryption.






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






35. Used in IPsec for two discreet purposes:






36. 'Encryption - where Peer X uses Peer Y






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






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






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






40. 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.






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






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






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






44. '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.'






45. 'MACs with hash algorithms -'






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






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






48. DoS attacks are more probable with this mode.






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






50. '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.'