【正文】 藏明文的模式，可能對明文進行主動攻擊。s data or the confidentiality of the data? From the perspective of the bank39。Nonrepudiation :The recipient can verify or confirm the signature of the signer, but cannot deny15. Suppose that Alice39。通過數(shù)字簽名能夠實現(xiàn)對原始報文的鑒別。發(fā)送方用自己的私人密鑰對這個散列值進行加密。s public key to decrypt the additional digital signature. If the two the same, then the receiver can verify the digital signature is the sender.2. Using the algorithm (hash)，Ensuring that once the message is changed or replaced，even if only has changed a data,will lead the digest to protect the integrity and authenticity of the message.3. Because only the sender has the private key, so it cannot deny the electronic file is not sent by it.翻譯：：計算：發(fā)送報文時，發(fā)送方用一個哈希函數(shù)從報文文本中生成報文摘要,然后用自己的私人密鑰對這個摘要進行加密，這個加密后的摘要將作為報文的數(shù)字簽名和報文一起發(fā)送給接收方。給兩個例子從日常生活使用雙重認證。7vrsaC: gimmeliborD D: ItgetNOsat例如：A. PokeGCTallPerson or kids end Good Cat Tall Play on kid Great Cool Top are like like8. Consider the ciphertext FALSZ ZTYSY JZYJK YWJRZ TYJZT YYNAR YJKYS WARZT YEGYY J, which was generated using an affine cipher with parameter a=7 and b=22. Decipher the message please.加密過程為：E(m)=(am+b)mod26解密過程為：c（m）=a^1(cb)mod26=7^1（c22）mod26=15(c22)mod26 所以仿射碼解密相對應的字母為0123456789101112明文ABCDEFGHIJKLM密文WDKRYFMTAHOVC13141516171819202122232425明文NOPQRSTUVWXYZ密文JQXELSZGNUBIP密文：FALSZ ZTYSY JZYJK YWJRZ TYJZT YYNAR YJKYS WARZT YEGYYJ明文： first the sentence and then the evidence said the queen.9. Consider the ciphertext QJKES REOGH GXXRE OXEO, which was generated using an affine cipher. Determine the constants aamp。答：機密性具有一定保密程度的信息只能讓有授權的人讀取和更改；完整性是防止或至少檢測出對信息進行未授權的修改；可用性是對于信息的合法擁有和使用者，在他們需要這些信息的任何時候，都應該保障他們能夠及時得到所需要的信息。 Integrity is to prevent or at least to detect unauthorized changes to information。 2 In the field of information security, Kerckhoffs’ Principle is like motherhood and apple pie, all rolled up into one.*Define Kerckhoffs’ Principle in the context of cryptography.（1）即使密碼系統(tǒng)的任何細節(jié)已為人悉知，只要密鑰未泄漏，它也應是安全的。帳戶所有者很少計算余額的千分之幾或千分之十分，必然繼續(xù)無視。1. In the movie Office Space, software developers attempt to modify pany software so that for each financial transaction, any leftover fraction of a cent goes to the developers, instead of going to the pany. The idea is that for any particular transaction, nobody will notice the missing fraction of a cent, but over time the developers will accumulate a large sum of money. This type of attack is sometimes known as a salami attack. Now, find a realworld example of a salami attack and expound how it works. The most typical scheme portrayed by a salami attack is that which involves an automated modification to financial systems and their data. For example, the digits representing currency on a bank39。The essence of this mechanism is its resistance to detection. Account owners rarely calculate their balances to the thousandths or tenthousandths of a cent, and, consequentially remain oblivious. Even if the discrepancies are noticed, most individuals have better things to do (like preserve their pride) than plain about an erroneous digit in some far off decimal place. The following (alleged) scenarios will demonstrate that slices need not always be tiny to evade detection. In fact, they can be rather large, as long as unsuspecting and/or ignorant victims are plentiful. 這種機制的本質是它的電阻檢測。事實上，他們可以是相當大的，只要不知情的和/或無知的受害者是豐富的。ATM using DES data encryption, is an cryptography system, sometimes the password does not leak, but criminals steal the money after know the identity information and bank card number .The security problem in this case are: personal information leakage, the loss of the property.3. Among the fundamental challenges in information security are confidentiality, integrity, and availability, or CIA. A. Define each of these ter