There are two general approaches to attacking a (1)encryption scheme.The first attack is known as cryptanalysis.Cryptanalytic attacks rely on the nature of the algorithm plus perhaps some knowledge of the general characteristics of the ( ) or even some sample plaintext- ciphertext pairs. This type of ( ) exploits the characteristics of the algorithm to attempt to deduce a specific plaintext or to deduce the key being used. If the attack succeeds in deducing the key, the effect is catastrophic: All future and past messages encrypted with that key are compromised. The second method, known as the ( )-force attack, is to try every possible key on a piece of ( ) until an intelligible translation into plaintext is obtained. On average, half of all possible keys must be tried to achieve success.（1）处应选________. A. streamB.symmetricC. asymmetricD.advanced
There are two general approaches to attacking a (1)encryption scheme.The first attack is known as cryptanalysis.Cryptanalytic attacks rely on the nature of the algorithm plus perhaps some knowledge of the general characteristics of the ( ) or even some sample plaintext- ciphertext pairs. This type of ( ) exploits the characteristics of the algorithm to attempt to deduce a specific plaintext or to deduce the key being used. If the attack succeeds in deducing the key, the effect is catastrophic: All future and past messages encrypted with that key are compromised. The second method, known as the ( )-force attack, is to try every possible key on a piece of ( ) until an intelligible translation into plaintext is obtained. On average, half of all possible keys must be tried to achieve success.
（1）处应选________.
（1）处应选________.
A. stream
B.symmetric
C. asymmetric
D.advanced
B.symmetric
C. asymmetric
D.advanced
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There are two general approaches to attacking a （ ）encryption scheme.The first attack is known as cryptanalysis.Cryptanalytic attacks rely on the nature of the algorithm plus perhaps some knowledge of the general characteristics of the （ ） or even some sample plaintext-ciphertext pairs. This type of （ ） exploits the characteristics of the algorithm to attempt to deduce a specific plaintext or to deduce the key being used. If the attack succeeds in deducing the key, the effect is catastrophic: All future and past messages encrypted with that key are compromised. The second method, known as the （ ）-force attack, is to try every possible key on a piece of （ ） until an intelligible translation into plaintext is obtained. On average, half of all possible keys must be tried to achieve success.A.stream B.symmetric C.asymmetric D.advancedA.operation B.publication C.plaintext D.ciphertextA.message B.knowledge C.algorithm D.attackA.brute B.perfect C.atribue D.re searchA.plaintext B.ciphertext C.sample D.code
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材料：Following a general average incident，ship agents and surveyors play a significant role．A ship agent，in addition to the normal duties of port and husbandry agency，will assist the master in the aftermath of a general average incident to make a declaration which complies with the local law and custom of the port．Once the average adjuster has confirmed that security has been obtained from all the interested parties，the agent is instructed by the ship owner to permit delivery of the cargo．If cargo has been discharged to lighten the vessel，or cargo has been transshipped to a final destination，the agent will be responsible for keeping full and complete records of all movements and expenditure attributable to the general average．After any incident，a large number of surveyors representing various interests will descend on the vessel．Some of these surveyors will not be involved directly in the general average process．However，if it has become necessary to sacrifice or discharge a part of the cargo before arrival at the final destination stated on the bill of lading，the ship owner will appoint surveyors to report on the condition and quantity of cargo．Such surveyors，usually called general average surveyors，will act in the interests of all the parties involved（and may also represent hull and machinery interests）．If possible，the account representing expenditure incurred should be examined and approved by the general average surveyor before settlement．问题：Which of the following is NOT correct as to the general average surveyors ___________．A.They may sometimes be involved into the examination and approval of general average expendituresB.They may sometimes be involved into the examination and approval of general average sacrificesC.They will act in the interests of all the parties involvedD.They will look at particularly the general average mattersWhat does this passage imply for the shipmasters when a general average incident occurred onboard ___________．A.He can rely on greatly the general average surveyorsB.He can rely on greatly the ship agentC.He can rely on greatly the interested partiesD.He can rely on greatly other surveyorsThe ship agent mentioned in the passage behaves ______．A.for the benefit of the cargo ownerB.for the benefit of the shipownerC.for the benefit of the salvorsD.for the benefit of the interested parties other than the aboveThe security required by the owner of ship and provided by relevant interested parties in general average cases is for the purpose of _______．① contributing to the losses and damages of general average nature；② securing all the general average contributions；③ Securing all the payment of Sue and Labour；④ contributing to the losses and damages of particular average nature．A.①③④B.①②③C.①②D.②③④请帮忙给出每个问题的正确答案和分析，谢谢！
Symmetric, or private-key, encryption is based on a secret key that is shared by both communcating parties. The （ ） party uses the secret key as part of the mathematical operation to encrypt （ ） text to cipher text. The receiving party uses the same secret key to decrypt the cipher text to plain text. Asymmetric, or public-key, encryption uses two different keys for each user: one is a （ ） key known only to this one user; the other is a corresponding public key, which is accessible to anyone. The private and public keys are mathematically related by the encryption algorithm. One key ia used for encyption and the other for decryption, depending on the nature of the communication service being implemented. In addition, public key encryption technoligies allow digital （_______） to be placed on messages. A digital signature uses the sender's private key to encrypt some portion of the message. When the message is received, the receiver uses the sender's （） key tp decipher the digital signature to verify the sender's identity.横线处应选（ ）。 A. interpretationB.signaturesC. encryptionD.decryption
There are two general approaches to attacking a ( )encryption scheme.The first attack is known as cryptanalysis.Cryptanalytic attacks rely on the nature of the algorithm plus perhaps some knowledge of the general characteristics of the ( ) or even some sample plaintext- ciphertext pairs. This type of ( ) exploits the characteristics of the algorithm to attempt to deduce a specific plaintext or to deduce the key being used. If the attack succeeds in deducing the key, the effect is catastrophic: All future and past messages encrypted with that key are compromised. The second method, known as the ( 4 )-force attack, is to try every possible key on a piece of ( ) until an intelligible translation into plaintext is obtained. On average, half of all possible keys must be tried to achieve success.（4）处应选_______. A. bruteB. perfectC. atribueD. research
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