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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 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.






2. A






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






4. Uses protocol number 50.






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






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






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






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






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






10. 'MACs with hash algorithms -'






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. '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.'






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






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






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






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






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






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






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






20. Uses protocol number 51.






21. '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.'






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






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






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






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






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






27. The DES algorithm that performs 3 times sequentially.






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






29. '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.'






30. Key exchange for IPSEC






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






32. One of the most popular tunneling protocols is






33. 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.






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






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






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






37. Act of encapsulating a packet within another packet.






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






39. 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.






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






41. More CPU intensive






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






43. Provides authentication and encryption of the payload.






44. Used in IPsec for two discreet purposes:






45. 'Encryption - where Peer X uses Peer Y






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






47. '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






48. The receiving device decrypts the data with the third key.






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






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