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






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






3. The DES algorithm that performs 3 times sequentially.






4. IPSEC Encryption is performed by


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






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






7. '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.'






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






9. 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.






10. 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.






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






12. Common key size is 1024 bits.






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






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






15. 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.






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






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






18. Act of encapsulating a packet within another packet.






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






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






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


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






23. Does not provide payload encryption.






24. More CPU intensive






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






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






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






28. A






29. 'Encryption - where Peer X uses Peer Y






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


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






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






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






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






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






36. Integrity checks are done


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






38. 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.






39. '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.'






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






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






42. Uses protocol number 50.






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






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






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






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






48. 'MACs with hash algorithms -'






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






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