計(jì)算機(jī)技術(shù)簡(jiǎn)介外文翻譯

1、<p><b>　　外文資料</b></p><p>　　Parts of computer technique brief introduction</p><p>　　Compendium</p><p>　　Computer technique more the renewal being placed in continuou

2、sly changes the on behalf inside, each a strenuous efforts for new technical emergence all coagulating numerous person.In this article, we simple introduction some of that.</p><p>　　Search Engines</p>

3、<p>　　Internet search tools fall into two camps：search engines, such as HotBot and AltaVista，and online directories，such as Yahoo and Lycos．The difference between the two is related to how they compile their site

4、 listings．Of course，there are exceptions to every rule．Some search utilities such as Ask Jeeves，combine the search engine and directory approaches into a single package，hoping to provide users with the best of both world

5、s． </p><p>　　In directory-based search services，the Web site listings are compiled manually．For example，the everpopular Yahoo dedicates staff resources to accept site suggestions from users review and catego

6、rize them，and add them to a specific directory on the Yahoo site．</p><p>　　You can usually submit your Web site simply by filling out an online form．On Yahoo,for example,you'll find submission informatio

7、n at www.yahoo.com/docs/info/include.html．Because human intervention is necessary to process，verify，and review submission requests，expect a delay before your site secures a spot in a directory-based search service． </

8、p><p>　　On the flip side，search engines completely automate the compilation process，removing the human component entirely． </p><p>　　A software robot，called a spider or crawler，automatically fetche

9、s sites all over the Web，reading pages and following associated links．By design，a spider will return to a site periodically to check for new pages and changes to existing pages． </p><p>　　Results from spider

10、ing are recorded in the search engine’s index or catalog．Given the wealth of information available on the Internet，it is not surprising that indexes grow to very large sizes．For example，the AltaVista index has recently b

11、een increased to top out at 350 million pages．This may seem like a mammoth number，but by all estimates it still represents less than 35 percent of all pages on the Web． </p><p>　　Because of the depth and bre

12、adth of information being indexed，there is usually a delay，sometimes up to several weeks，between the time a site has been“spidered”and when it appears in a search index．Until this two-step process has been completed，a si

13、te remains unavailable to search queries． </p><p>　　Finally，the heart of each search engine is an algorithm that matches keyword queries against the information in the index，ranking results in the order the

14、algorithm deems most relevant． </p><p>　　Because the spiders，resulting indexes，and search algorithms of each search engine differ，so do the search results and rankings across the various search engines．This

15、explains why a top 10 site in HotBot may not appear near the top of Alta Vista when the same keyword search criterion is entered． </p><p>　　In addition，many，but not all，search utilities also reference metata

16、gs—invisible HTML tags within documents that describe their content—as a way to control how content is indexed．As a result，proper use of metatags throughout a site can also boost search engine ranking</p><p>

17、;　　Advanced Encryption Standard</p><p>　　For the past three years，the National Institute of Standards and Technology (NIST) has been working to develop a new encryption standard to keep government informatio

18、n secure．The organization is in the final stages of an open process of selecting one or more algorithms，or data-scrambling formulas，for the new Advanced Encryption Standard (AES) and plans to make adecision by late summe

19、r or early fall．The standard is slated to go into effect next year．</p><p>　　AES is intended to be a stronger，more efficient successor to Triple Data Encryption Standard (3DES)，which replaced the aging DES，w

20、hich was cracked in less than three days in July 1998． </p><p>　　“Until we have the AES，3DES will still offer protection for years to come．So there is no need to immediately switch over，”says Edward Roback，a

21、cting chief of the computer security division at NIST and chairman of the AES selection committee．“What AES will offer is a more efficient algorithm．It will be a federal standard，but it will be widely implemented in the

22、IT community．” </p><p>　　According to Roback，efficiency of the proposed algorithms is measured by how fast they can encrypt and decrypt information，how fast they can present an encryption key and how much in

23、formation they can encrypt． </p><p>　　The AES review committee is also looking at how much space the algorithm takes up on a chip and how much memory it requires．Roback says the selection of a more efficient

24、 AES will also result in cost savings and better use of resources． </p><p>　　“DES was designed for hardware implementations，and we are now living in a world of much more efficient software，and we have learne

25、d an awful lot about the design of algorithms，”says Roback．“When you start multiplying this with the billions of implementations done daily，the saving on overhead on the networks will be enormous．” </p><p>　

26、　The process of selecting the algorithm for AES has been notable for its openness and transparency．This is a marked departure from the government's past inclination toward secrecy in discussing encryption standards，w

27、hich led to the public cracking of DES after critics questioned the government's assertion that the standard was still secure． </p><p>　　NIST kicked off the selection process in September 1997．Conference

28、s were held in August 1998 and March 1999；cryptographers from around the world discussed the algorithm candidates and helped narrow the list to 15 and then to five finalists：IBM's MARS；RSA Laboratories* RC6 ；Joan Dae

29、men and Vincent Rijmen's Rijndael；Ross Andersen，Eli Baham and Lars Knudsen's Serpent；and Counterpane Labs* Twofish．</p><p>　　While most evaluators of the algorithms want to avoid complexity by select

30、ing one to serve as a standard，there's a minority that wants to select more than one．</p><p>　　Digital Wallets</p><p>　　A digital wallet is software that enables users to pay for goods on t

31、he Web. It holds credit-card numbers and other personal information such as a shipping address ．Once entered，the data automatically populates order fields at merchant sites.</p><p>　　When using a digital wal

32、let，consumers don't need to fill out order forms on each site when they purchase an item because the information has already been stored and is automatically updated and entered into the order fields across merchant

33、sites. Consumers also benefit when using digital wallets because their information is encrypted or protected by a private software code. And merchants benefit by receiving protection against fraud． </p><p>　

34、　Digital wallets are available to consumers free of charge，and they're fairly easy to obtain ．For example，when a consumer makes a purchase at a merchant site that's set up to handle server-side digital wallets，he

35、 types his name and payment and shipping information into the merchant's own form ．At the end of the purchase，one consumer is asked to sign up for a wallet of his choice by entering a user name and password for futur

36、e purchases ．Users can also acquire wallets at a wallet vendor's site.</p><p>　　Although a wallet is free for consumers，vendors charge merchants for wallets ． </p><p>　　Digital wallets come

37、in two main types :client-side and server- side ．Within those divisions are wallets that work only on specific merchant sites and those that are merchant agnostic ．</p><p>　　Client-based digital wallets，the

38、older of the two types，are falling by the wayside，according to analysts，because they require users to download and install software ．A user downloads the wallet application and inputs payment and mailing information ．At

39、that point，the information is secured and encrypted on the user's hard drive ．The user retains control of his credit card and personal information locally ．</p><p>　　With a server-based wallet，a user fil

40、ls out his personal information，and a cookie is automatically downloaded ．（A cookie is a text file that contains information about the user ．）In this scenario，the consumer information resides on the server of a financial

41、 institution or a digital wallet vendor rather than on the user's PC ． </p><p>　　Server-side wallets provide assurance against merchant fraud because they use certificates to verify the identity of all p

42、arties ．When a party makes a transaction，it presents its certificate to the other parties involved ．A certificate is an attachment to an electronic message used to verify the identity of the party and to provide the rece

43、iver with the means to encode a reply ．</p><p>　　Furthermore，the cardholder's sensitive data is typically housed at a financial institution，so there's an extra sense of security because financial env

44、ironments generally provide the highest degree of security ．</p><p>　　But even though wallets provide easy shopping online， adoption hasn't been widespread ． </p><p>　　Standards are pivotal

45、to the success of digital wallets.</p><p>　　New wireless LANs standard</p><p>　　With portable computers and wireless LANs,users can enjoy greater productivity while away from their desks ,whethe

46、r they are in conference rooms, public areas or remote offices.<BR>Until recently , however,wireless LANs were too slow for most enterprise applications.based on the IEEE 802.11 standdrd,they ran at 1M to 2M bit/se

47、c.</p><p>　　Now a new high -rate extension to the standard ,802.11b, lets wireless networks support data rates to 11M bit/sec.</p><p>　　Ratified in 1997 ,the original 802.11 standardunited the w

48、ireless industury by defining a low-level protocol architecture that worked with conventional upper-layer enterprise protocol stacks . also, 802.11 maintained compatibility with the three most popular radio transmission

49、types: direct sequence spread spectrum,frequency-hopping spread spectrum,and infrared.</p><p>　　Essentially,this new architecture added intelligence at the medium access control(MAC) layer 2 and at the physi

50、cal (PHY) layer 1, fosteing cooperation between the two layers in performing the critical tasks involved with initiating and maintaining wireless communi-cations.</p><p>　　For instance ,to ensure reliability

51、 of the wireless link ,MAC and PHY work togetherto determine if a clear path exists before they start a transmission.</p><p>　　During transmission, they employ special collision -avoidance and arrival-acknow

52、ledgment techniques that are not required in wired ethernet LANs.</p><p>　　in september 1999,the IEEE approved a new designation, known as 802.11.intended to retain the error-correction,security,powermanagem

53、ent and other advantages of the original , a key ingredient-a thchnique for increasing bandwidth to 11M bit/sec.</p><p>　　Called complementary code keying (CCK) the technique works only in conjunction with t

54、he DSSS technology sprcified in the original standard . it does net work with frequency-hopping or infrared transmissions.</p><p>　　What CCK does is apply sophisticated mathematical formulas to the DSSS code

55、s, a permitting the code to represent a greater volume of informitter is now able to send multiple bits of information with each DSSS code ,enough to make possible the 11M bit /sec in the original standard .</p>&

56、lt;p>　　The 802.11b standard benefits users by delivering wireless ethernet speeds of 11M bit/sec that can reliably support everyday business applications,e-mail,internet and server network access.</p><p>

57、　　With support from the new wireless ethernet from the new wireless ethernet compatibility alliance ,founded by 3com,lucent,nokia and several other companies in the wireless LAN business,the new standard will also promis

58、e certified interoperability across multivendor platforms.</p><p>　　Finally, the 802.11b standard serves as a clamoring for a simplified wireless LAN landscpape.</p><p>　　Vendors can now focus o

59、n a single ,high-speed standard , and users can cut through the clutter of wireless options by fovusing on a standard that delivers multibvendor interoperability and the performance to meet their application needs.</p

60、><p>　　Data Communication Systems</p><p>　　There are five basic types of data communication system:</p><p>　　Off-line data transmission is simply the use of a telephone or similar link

61、 to transmit data without involving a computer system .The equipment used at both ends of such a link is not part of a computer, or at least does not immediately make the data available for computer process, that is, the

62、 data when sent and/or received are 'off-line'. This type of data communication is relatively cheap and simple.</p><p>　　Remote batch is the term used for the way in which data communication technolo

63、gy is used geographically to separate the input and /or output of data from the computer on which they are processed in batch mode.</p><p>　　On-line data collection is the method of using communications tech

64、nology to provide input data to a computer as such input arises-the data are then stored in the computer (say on a magnetic disk) and processed either at predetermined intervals or as required.</p><p>　　Enqu

65、iry-response systems provide ,as the term suggests ,the facility for a user to extract information from a computer .The enquiry facility is passive ,that is ,does not modify the information stored .The interrogation may

66、be simple ,for example ,'RETRIEVE THE RECORD FOR EMPLOYEE NUMBER 1234' or complex .Such systems may use terminals producing hard copy and /or visual displays.</p><p>　　Real-time systems are those in

67、which information is made available to and processed by a computer system in a dynamic manner so that either the computer may cause action to be taken to influence events as they occur (for example as in a process contro

68、l application) or human operators may be influenced by the accurate and up-to-date information stored in the computer, for example as in reservation systems.</p><p>　　How TCP/IP Works</p><p>　　O

69、ver the past few years ,one of the most written－about network topics has been IP. But even with all this attention, few, if any ,stories have traced the protocol\'s basic workings, that is ,how routers and Layer 3 sw

70、itches act upon IP information to move Ethernet packets across the network..</p><p>　　As a point of referenced, bear in mind that IP is a member of the TCP/IP protocol suite.</p><p>　　TCP functi

71、ons at the Open Systems Interconnection(OSI)transport layer, or Layer 4.Its chief responsibility is to ensure reliable end－to－end connectivity. IP, located one layer down, at the OSI network layer, or Layer 3, communicat

72、es the addresses of each packet\'s sender and receiver to the routers along the way. Routers and Layer 3 switches can read IP and other Layer 3 protocols .This information ,combined with routing tables and other netw

73、ork intelligence ,is all it takes to get across the ro</p><p>　　The routing process begins with an IP address that is unique to the sending end station .End stations may be assigned permanent IP addresses or

74、 they may borrow them as needed from a Dynamic Host Configuration Protocol (DHCP) server or other service.</p><p>　　Each packet carries a source address, which under current (IPv4) specifications is 32 bits

75、long .In its header, each packet also carries the IP address of the final destination.</p><p>　　If the sending end station determines that the destination address is not local ,the packet goes to a first－h(huán)op

76、 router ,typically one that is close and has been preassigned to the sender.</p><p>　　The router inspects the packet\'s IP address and performs a route table lookup to see if the destination end station

77、resides on the local (physically connected) network, typically called an IP subnet .An IP subnet usually is assigned to each of the router\'s network interfaces.</p><p>　　If the destination IP address is

78、 local ,the router searches an internal store of IP addresses and local－device Media Access Control(MAC) addresses. This store is known as the Address Resolution Protocol (ARP) cache. ARP is the universal tool for matchi

79、ng IP addresses to MAC addresses. If the destination\'s MAC address appears, the router installs that MAC address in the packet header (removing its own MAC address because that\'s no longer needed) and sends the

80、 packet to the destination end stati</p><p>　　In the event that the destination MAC address does not appear in the ARP cache ―it might have timed out ,for instance― the router must broadcast an ARP request t

81、o the subnet referenced by the packet\'s destination IP address .The end station with that IP address responds, sending back its MAC address .The router updates its cache, installs the new MAC address into the packet

82、 header and launches the packet. If the route table lookup shows that the packet is destined for a non-local subnet, the ro</p><p><b>　　中文翻譯</b></p><p><b>　　部分計(jì)算機(jī)技術(shù)簡(jiǎn)介</b>

83、</p><p><b>　　摘要</b></p><p>　　計(jì)算機(jī)技術(shù)更處于不斷的更新?lián)Q代中，每一種新技術(shù)的出現(xiàn)都凝聚了無數(shù)人的心血。在這篇文章中，我們簡(jiǎn)單介紹一些。</p><p><b>　　搜索引擎</b></p><p>　　因特網(wǎng)搜索工具分為兩大陣營(yíng)：搜索引擎，如HotBot和Alta

84、Vista，以及在線目錄，如Yahoo和Lycos。兩者間的差別與它們?nèi)绾尉幾W(wǎng)站編目有關(guān)。當(dāng)然，對(duì)任何規(guī)律都有例外。有些搜索實(shí)用程序，如Ask Jeeves，把搜索引擎和目錄方法合并成單一的軟件包，希望把這兩個(gè)陣營(yíng)中最好的東西提供給用戶。 </p><p>　　在基于目錄的搜索服務(wù)中，Web網(wǎng)站編目是手工編撰的。比如一直流行的Yahoo就指定專門的人力資源來接受用戶對(duì)網(wǎng)站的建議，并對(duì)建議進(jìn)行評(píng)價(jià)和分類，再把它們

85、加到Y(jié)ahoo網(wǎng)站上特定目錄中。</p><p>　　通常是通過簡(jiǎn)單地填寫在線表格就能把你的網(wǎng)站信息提交給(搜索引擎)。例如，在Yahoo網(wǎng)站上，你可以在www．yahoo．com/docs/info/include．htm1上找到提交信息。由于人工干預(yù)對(duì)處理、驗(yàn)證和評(píng)價(jià)提交請(qǐng)求是必要的，所以在網(wǎng)站在基于目錄的搜索服務(wù)中捕捉到一處之前，可望有些延遲。 </p><p>　　另一方面，搜索引

86、擎完全實(shí)現(xiàn)了編撰過程的自動(dòng)化，徹底消除了人工干預(yù)。 </p><p>　　一個(gè)叫做蜘蛛或爬蟲的軟件機(jī)器人自動(dòng)地在整個(gè)Web上取出站點(diǎn)，閱讀頁面和跟隨相關(guān)的鏈接。通過設(shè)計(jì)，蜘蛛可以周期性地返回到站點(diǎn)，檢查新的頁面和修改已有頁面。 </p><p>　　蜘蛛爬行得到的結(jié)果記錄在搜索引擎的索引或目錄中。已知了因特網(wǎng)上可資利用的信息的價(jià)值，對(duì)索引擴(kuò)張到非常大的規(guī)模是不會(huì)感到驚訝的。例如，AltaV

87、ista的索引最近已增至3．5億頁而名列前茅。這個(gè)數(shù)字看來好像非常大，但總體估計(jì)它僅代表了Web上不足35%的頁面。 </p><p>　　由于已編索引的信息的深度與廣度(非常大)，所以通常在“蜘蛛爬行過”站點(diǎn)的時(shí)間與出現(xiàn)在搜索索引中的時(shí)間之間有一個(gè)延遲，有時(shí)多達(dá)幾周。只有這兩步的過程完成之后，站點(diǎn)才能供搜索查詢使用。 </p><p>　　最后，每個(gè)搜索引擎的心臟是一種算法，它將關(guān)鍵字查

88、詢與索引中的信息匹配起來，并按算法認(rèn)為最有關(guān)聯(lián)的順序把結(jié)果列出。</p><p>　　由于每種搜索引擎的蜘蛛、產(chǎn)生的索引和搜索算法都是不一樣的，所以在不同搜索引擎上的搜索結(jié)果和排列次序是不同的。這就解釋了為什么當(dāng)相同的關(guān)鍵字搜索準(zhǔn)則輸入進(jìn)去時(shí)，HotBot中排在最前面的10個(gè)站點(diǎn)不會(huì)出現(xiàn)在 AltaVista中最前面的站點(diǎn)中。</p><p>　　此外，很多(但不是所有的)搜索實(shí)用程序也引

89、用元標(biāo)記(文檔中用來描述其內(nèi)容的、看不見的HTML標(biāo)記)，作為控制內(nèi)容如何編索引的方法。因此，在整個(gè)站點(diǎn)中正確使用元標(biāo)記也能提高(此站點(diǎn))在搜索引擎中的排列名次。</p><p><b>　　先進(jìn)加密標(biāo)準(zhǔn)</b></p><p>　　在過去三年中，（美國(guó)）國(guó)家標(biāo)準(zhǔn)與技術(shù)局（NIST）已在研究開發(fā)一種新的加密標(biāo)準(zhǔn)，以確保政府的信息安全。該組織目前正處于為新的先進(jìn)加密標(biāo)準(zhǔn)

90、（AES）選擇一個(gè)或幾個(gè)算法或數(shù)據(jù)打亂公式的開放過程的最后階段，并計(jì)劃在夏末或秋初作出決定。此標(biāo)準(zhǔn)內(nèi)定明年實(shí)施。</p><p>　　AES預(yù)定為比三層數(shù)據(jù)加密標(biāo)準(zhǔn)(3DES)更強(qiáng)、更高效的后續(xù)標(biāo)準(zhǔn)，3DES替代了老化的DES加密標(biāo)準(zhǔn)，DES在1998年7月在不到三天的時(shí)間內(nèi)就被破譯了。</p><p>　　NIST計(jì)算機(jī)安全部的代理主管兼AES選擇委員會(huì)主席Edward Roback說：

91、“在我們擁有AES之前，3DES還將在今后幾年提供保護(hù)。所以沒有必要馬上轉(zhuǎn)換。AES所提供的是一種更有效的算法。它將是一項(xiàng)聯(lián)邦標(biāo)準(zhǔn)，但它將在IT界廣泛實(shí)施?！?</p><p>　　據(jù)Roback稱，提議中的算法的效率是通過對(duì)信息加密和解密有多快、給出加密密鑰有多快以及能對(duì)多少信息加密等幾個(gè)方面進(jìn)行測(cè)量的。 </p><p>　　AES評(píng)價(jià)委員會(huì)也要看算法占據(jù)芯片上多少空間和需要多少內(nèi)存。

92、Roback說，選擇一個(gè)更高效的AES也會(huì)帶來成本的節(jié)省和資源的更好利用。 </p><p>　　Roback說：“DES是為硬件實(shí)現(xiàn)而設(shè)計(jì)的，而我們現(xiàn)在處于軟件更高效的世界，我們對(duì)算法的設(shè)計(jì)有極多的了解。當(dāng)我們開始大規(guī)模使用此算法，每天實(shí)現(xiàn)幾十億次的加密時(shí)，（算法帶來的）網(wǎng)絡(luò)開銷的節(jié)省將是巨大的?！?</p><p>　　為AES選擇算法的過程是以其公開性和透明度稱著。這標(biāo)志著政府從以往

93、討論加密標(biāo)準(zhǔn)時(shí)傾向于保密的做法一刀兩斷，它導(dǎo)致了政府在斷言DES 標(biāo)準(zhǔn)仍是安全時(shí)被公開破譯。</p><p>　　NIST在1997年9月開始這個(gè)選擇過程。1998年8月和 1999年3月召開了會(huì)議，來自全世界的密碼專家討論了候選的算法，幫助把算法縮小到15 個(gè)，最后到了5個(gè)：IBM的MARS算法，RSA實(shí)驗(yàn)室的RC6算法、Joan Daemen和Vincent Rijmen兩人的Rijndael算法、Eli B

94、aham和Lars Knudsen兩人的Serpent算法以及Counterpane 實(shí)驗(yàn)室的Twofish算法。 </p><p>　　大多數(shù)算法鑒定者都選擇一個(gè)作標(biāo)準(zhǔn)以避免復(fù)雜性，但也有一小部分人要選擇多個(gè)算法。</p><p><b>　　數(shù)字錢包</b></p><p>　　數(shù)字錢包是一種能使用戶在Web網(wǎng)上支付貨款的軟件。它保存信用

95、卡號(hào)碼和其它個(gè)人信息，如送貨地址。數(shù)據(jù)一旦被輸入，就自動(dòng)轉(zhuǎn)移到商家網(wǎng)站的訂貨域。</p><p>　　使用數(shù)字錢包時(shí)，當(dāng)消費(fèi)者購買物品時(shí)，不需要填寫每個(gè)站點(diǎn)上的訂單，因?yàn)樾畔⒁呀?jīng)存儲(chǔ)了，并自動(dòng)更新和進(jìn)入到廠商站點(diǎn)的訂貨域。消費(fèi)者使用數(shù)字錢包時(shí)也能得到好處，因?yàn)樗麄兊男畔⒈患用芰耍从伤饺塑浖a加以保護(hù)。商家也避免了受騙而得到保護(hù)，也從中獲益。</p><p>　　對(duì)消費(fèi)者來說，數(shù)字錢包是

96、免費(fèi)的，可以相當(dāng)容易得到。例如，當(dāng)消費(fèi)者在建立了處理服務(wù)器端數(shù)字錢包的商家網(wǎng)站上購買東西時(shí)，他把其名字、付款額和送貨信息輸入到商家自己的表格中。在購買結(jié)束時(shí)，他被要求為他選擇的錢包簽上用戶名和今后購買時(shí)的口令。用戶也能從錢包供應(yīng)商的站點(diǎn)上得到錢包。</p><p>　　雖然錢包對(duì)消費(fèi)者是免費(fèi)的，但(錢包)供應(yīng)商對(duì)商家使用錢包要收費(fèi)。 </p><p>　　數(shù)字錢包分兩大類型：客戶端和服務(wù)器

97、端（數(shù)字錢包）。在這些分類中是那些只在某些商家網(wǎng)站上工作的錢包和那些商家不可知的錢包。</p><p>　　基于客戶的數(shù)字錢包是兩種錢包中較陳舊的一種，據(jù)分析人士稱，這類錢包已開始沒人理睬了，因?yàn)樗鼈円笥脩粝螺d和安裝軟件。用戶下載錢包的應(yīng)用程序和輸入付款額和郵寄信息。在這個(gè)意義上，信息是安全的，并在用戶的硬盤上進(jìn)行了加密。用戶在本地獲得對(duì)其信用卡和個(gè)人信息的控制。</p><p>　　使

98、用基于服務(wù)器的錢包時(shí)，用戶填寫其個(gè)人信息，并自動(dòng)下載點(diǎn)心文件（點(diǎn)心文件是一個(gè)包括了有關(guān)用戶信息的文本文件）。在這種情況下，消費(fèi)者的信息駐留在金融機(jī)構(gòu)或者數(shù)字錢包供應(yīng)商的服務(wù)器上，而不是用戶的PC機(jī)上。</p><p>　　服務(wù)器端錢包提供了針對(duì)商家欺騙的安全措施，因?yàn)樗鼈兪褂米C書，來驗(yàn)明各方的身份。當(dāng)一方進(jìn)行交易時(shí)，它向涉及的另一方提交證書。證書附著在電子報(bào)文上，用于驗(yàn)明另一方身份，并向接收方提供對(duì)回答進(jìn)行編碼的

99、手段。</p><p>　　另外，信用卡持有人的敏感信息一般保存在金融機(jī)構(gòu)內(nèi)，由于金融環(huán)境通常提供最高等級(jí)的安全性，因而這又是一種額外的安全措施。</p><p>　　但是即使錢包提供了方便的網(wǎng)上購物，尚未被廣泛采用。</p><p>　　標(biāo)準(zhǔn)化是數(shù)字錢包能否成功的關(guān)鍵。</p><p><b>　　新的無線局域網(wǎng)標(biāo)準(zhǔn)</b&

100、gt;</p><p>　　有了便攜式和無線局域網(wǎng)，用戶在離開其辦公桌的時(shí)候，不管是在會(huì)議室、公共區(qū)域還是在遠(yuǎn)處辦公室，都能享有更高的生產(chǎn)效率。</p><p>　　然而，時(shí)至今日，無線局域網(wǎng)對(duì)多數(shù)企業(yè)應(yīng)用來說還是太慢。依據(jù)IEEE802.11標(biāo)準(zhǔn)，他們運(yùn)行速度為1兆至2兆位/秒。</p><p>　　現(xiàn)在對(duì)此標(biāo)準(zhǔn)的一個(gè)新的更高速擴(kuò)展，能讓無線網(wǎng)支持高達(dá)11兆位/秒