step_by_step_3000 第一册第4单元ppt

合集下载

MD4 散列算法step-by-step

MD4 散列算法step-by-step

下面给出MD4 下面给出MD4中,轮1,2,3的完整描述 的完整描述: MD4中的第一轮: 中的第一轮: 中的第一轮 1°A=(A+f(B,C,D)+X[0])<<3, 2°D=(D+f(A,B,C)+X[1])<<7, 3°C=(C+f(D,A,B)+X[2])<<11, 4°B=(B+f(C,D,A)+X[3])<<19, 5°A=(A+f(B,C,D)+X[4])<<3, 6°D=(D+f(A,B,C)+X[5])<<7, 7°C=(C+f(D,A,B)+X[6])<<11, 8°B=(B+f(C,D,A)+X[7])<<19; 9°A=(A+f(B,C,D)+X[8])<<3, 10°D=(D+f(A,B,C)+X[9])<<7,
MD4散列算法(或称信息摘要算法) MD4散列算法(或称信息摘要算法) 散列算法
Rivest(RSA公司首度科学家,MIT博士,1990年提出 MD4,1991年提出增强版MD5。1992年提出SHA公布 于1992年1月31日的联帮记录上,并于1993年5月11日采 纳作为标准。这些散列函数运算起来非常快,都源于同 一思想。它们对于签名非常长的消息是适用的。 为了讲清Rivest的想法,还是从MD4讲起。 MD4:给定一个消息比特串x,使用如下算法来构造M: • 设d=447-(|x|(mod 512)) • l表示|x|(mod 264)的二进制表示,|l|=64 • M=x||1||Od||l
f(X,Y,Z)=(X∧Y)V( X ∧Z) g(X,Y,Z)=(X∧Y)V(X∧Z)V(Y∧Z) h(X,Y,Z)=X⊕Y⊕Z 设计的MD4是非常快的,且实际上在Sun SPARC工作 站上软实现可达速度1.4M bytes/S。另一方面,具体地谈 论象MD4这样的散列函数的安全性是困难的,因为它不 是基于一个已经很好研究过的问题,如大整数分解,离 散对数问题。所以,象采用DES的情况一样,仅能在一段 时间内取得对该体制的安全性的信任。 另外,MD4的增强版本称为MD5,于1991年提出。 MD5使用了四轮来代替MD4的三轮,且运算速度大约比 MD4慢30%。(在SPARC工作站上大约为0.9Mbytes/S)。

step-by-step-3000-第一册第5单元ppt

step-by-step-3000-第一册第5单元ppt

A
• Now we often hear network used in connections with broadcasting. The Barnhart Dictionary of New English says that as early as 1914, people used it to mean a connected system of radio stations. This meaning continues to be popular. A more modern use of the word “network” is linked to computers. A network is a system that links a number of computers together. Networks make it possible for people who use computers to share information in costly equipment. Many companies and government agencies share the same computer network. The computers are linked through a main computer or through special lines. Some people are able to do their jobs from their home computers.
• Since time is getting short, has the Net given us truly short and clear ways to say good-bye? Try TAFN (that’s all for now), and BCNU (be seein’ you).

英语外研版第一册课件:Unit 4 Meeting the muse Secti_1

英语外研版第一册课件:Unit 4 Meeting the muse Secti_1

.Hale Waihona Puke Such developments are making the line between art
and technology 4. less distinct .
We don't know where technology will take art next, but we can definitely 5. expect the unexpected .
Step 3 Reading for the details. Choose the best answer according to the text.
1.What have caused a combination of art and technology? A.The advances of technology. B.The thoughts of modern artists. C.Roman sculptures in the Louvre. D.Chinese paintings in the Palace Museum.
Positive effects Art is 1. more accessible fore.
Possible problems to us than ever be- It has raised questions over 3. its overall quality .
We can take part in 2. its creation
答案 D
Step 2 Reading for the structure.
Fill in the following blanks with proper words.
Today, technological advances have led to a combination of art and technology.

step by step 3000 第四册Unit 4课件

step by step 3000 第四册Unit 4课件

4.
Depending on your major. Liberal arts grads including English, and psychology majors once snapped up by marketing firms and dot coms will now likely have a tougher time finding work. But majors like computer science, nursing, accounting and finance are still hot, and salaries for those jobs are on the rise.
2.
In a study done by the National Association of Colleges and Employers last fall, companies surveyed planned to hire 25% more college grads this year. In an updated study this spring, those same companies reduced projections to 18%, still a significant increase.
Companies
renege on
in tech sector slow college recruiting /
(Intel,
Dell, etc. ) job offers
M
-- Michael Hallkas K -- Keren Aloya C Chris Peterson B -- Bill Coleman

step-by-step3000-Unit4答案幻灯片课件

step-by-step3000-Unit4答案幻灯片课件

▪ 3) image: to produce a picture especially by means of other than visible light; to cause (light or shadow) to fall into space or (a picture) to fall on a surface
▪ E.g.The company has an annual turnover of $75 million
▪ 8) in excess of: more than
▪ 9) audit 审计, 查帐: to make an official examination of (the accounts of a business)
Teaching focuses and difficulties:
▪ The grasping of the listening skills of giving outline;
▪ The grasping of new expressions and language points;
▪ The understanding of the background knowledge;
▪ 4) administration: the management or direction of the affairs of a business, government, etc.
▪ 5) dynamic: (esp. of people) full of activity, new ideas, the will to succeed, etc.
▪ Section A ▪ Step 1 New words and phrases

step by step 3000 Unit 4

step by step 3000 Unit 4

Part 1 Warming up A 1. To Mars / March of next year. 2. Because of a mechanical problem. 3. 5 males and 2 females. 4. NASA / At the end of September, 83 days after landing. 5. To return home at the Kennedy Space Center after completing repairs on the Hubble Telescope.
Part 1 Warming up A 4.The United States Space Agency NASA says it’s given up any real hope of reviving its space probe on Mars. The spacecraft Pathfinder made its last transmission of scientific data from the surface of Mars at the end of September, 83 days after landing. 5.The U.S. space shuttle Endeavor is preparing to return home in triumph after completing repairs on the Hubble Telescope. The Endeavor’s scheduled to land Monday at the Kennedy Space Center on Florida’s Atlantic coast, returning to the site where the mission began eleven days ago.

step_by_step_3000_第一册第12单元ppt分解

step_by_step_3000_第一册第12单元ppt分解
Some people learn best by listening. They are called hearing learners. And others learn best by reading or looking at pictures. They are called visual learners. And some learn best by touching and doing things. They are called tactile learners. Now scientists don’t know why people use one sense more than the others. Maybe the sense they use most just works best for them.
Unit 12
Dictation
Item one vocabulary
Sense Hearing learner Visual learner Tactile learner Scientist
感官 听觉学习者 视觉学习者 触觉学习者 科学家
Item one
Different people have different ways of learning. We call this your “learning style”, and it’s based on your senses. To learn, you need to use your different senses – hearing, seeing, touching, etc., to bring information to your brain. Now, most people use one of their senses more than the others.

最新step by step 3000 第一册第1单元ppt上课讲义

最新step by step 3000 第一册第1单元ppt上课讲义

favor Canada spectacular west coast British Columbia New Zealand Auckland
喜爱 加拿大 壮观的,雄伟的 西海岸 英国的,大不列颠的 哥伦比亚 新西兰(太平洋南部岛国) 奥克兰(新西兰一港市)
A Vocabulary continue
A Vocabulary continue
innovation excel debate drama excellence Victoria serve approximately
改革 优于,擅长于 辩论 戏剧文学,戏剧 卓越,杰出 维多利亚 为……服务 大约,近似
A Vocabulary continue
step by step 3000 第一册 第1单元ppt
Education Is a key
• Part I Warming up • Part II Educational systems • Part III University life • Part VI University campus
situate cosmopolban Boston enrollment
使位于……的地位 世界性的 刺激,激励 哈佛 英亩(1英亩=4046.856 平方 米) 城市的,市区的 波士顿 登记,注册,招收
A Vocabulary continue
African entire continent spaceship Voyage Secretary General
The United Nations
非洲的 全部的 洲,大陆 宇宙飞船,太空船 这里指太空船的名字航天号 秘书长 联合国
B answers
1. 2,700 languages / 7,000 dialects / regional / pronunciation
  1. 1、下载文档前请自行甄别文档内容的完整性,平台不提供额外的编辑、内容补充、找答案等附加服务。
  2. 2、"仅部分预览"的文档,不可在线预览部分如存在完整性等问题,可反馈申请退款(可完整预览的文档不适用该条件!)。
  3. 3、如文档侵犯您的权益,请联系客服反馈,我们会尽快为您处理(人工客服工作时间:9:00-18:30)。

B
2. A hug When good friends meet in Russia, they often hug each other. This is true for both women and men. Russia isn't the only place where friends hug. In Brazil, for example, friends also hug each other in greeting. In Brazil, the hug is called an abraco.
B
1. A bow Around the world, there are many different ways to greet people. Bowing is the traditional way of greeting in Northeast Asian countries like Korea and Japan. This picture, for example, shows how Japanese women bow. In Japan, when you bow, you don't look directly at the other person's eyes. But in Korea, it's important to see the other person's face when you bow. In both countries, people bow to show respect.
B
3. A strong, short handshake You know how to shake hands. This is common in many countries. But it isn't always done the same way. In the United States and Canada, for example, people usually give a strong, short handshake. It's short but rather firm.
A
4. Japan • Woman: May I help you? • Man: I'm going to stay with a family in Japan. I need to get something for them. • Woman: Pen sets are always a good gift. • Man: Oh, that's a good idea. Let's see ... There are sets with a pen and pencil ... And bigger sets with four pens. • Woman: Don't give a set of four pens ---- in fact, don't give four of anything. It's bad luck. The Japanese word for "four" sounds like the word for "death". • Man: Thanks for telling me. I'll take the pen and pencil set. • Woman: Good choice. These sets make very good gifts. After all, pens write in any language. • Man: Uh ... Yeah. Right.
anything as a
A
1. Argentina • Woman: This is interesting. Did you know that in Argentina you should never give clothing unless you know the person really well? • Man: Don't give clothing? Why not? • Woman: Clothing ---- even things like ties ----- are too personal. Only good friends give them. • Man: Huh? I never thought of a tie as being personal ... Just uncomfortable. What should you bring? • Woman: I don't know. Maybe something for the house.
C
• The word "holiday" comes from the words "holy" and "day". Originally holidays were holy or religious days. Nowadays holidays include national, seasonal and historical days of celebration. Here are some traditional holidays in some countries. February 14 is Valentine's Day. It is observed in some European and North American countries. People send cars or gifts expressing love and affection sometimes anonymously to their sweethearts or friends. Feast of Dolls in Japan falls on March 2. It is observed there in honor of girls. Feast of Banners in Japan is on May 5. It is observed in honor of boys. May 5 is Dragon Boat Festival in China and is held according to the Chinese Lunar Calendar. People eat rice cakes and hold dragon boat races to commemorate the ancient scholar ---- statesman Qu Yuan. August 15 is Mid-Autumn Festival in China. It is held according to the Chinese Lunar Calendar. People eat moon cakes while looking at the bright full moon.
C vocabulary
Holy Originally Religious Historical Valentine’s day Observe Affection Anonymously 神圣的,圣洁的 起初,原本 宗教 历史的 情人节 遵守,遵循 感情,喜爱 匿名地
C vocabulary
Sweetheart Feast Doll In honor of Banner Dragon Boat Festival Chinese Lunar Calendar Commemorate 情人,爱人 盛会,宴会 玩偶,娃娃 为了向……表示敬意 旗帜,横幅 龙舟节,端午节 中国农历 纪念
Unit 4
Approaching Culture
Approaching Culture
Part I Warming up Part II Places to enjoy Part III Life here and there Part IV International business
Part I Warming up
C vocabulary
Sew Parade Reception Saint Patrick Ireland AnniveБайду номын сангаасsary Missionary Patron saint 缝纫 游行 接待,接见 圣帕特里克 爱尔兰岛 周年纪念 传教士 守护神
C vocabulary
Saint Movable Philadelphia Sweden Denmark 圣徒,圣人 可移动的 费城 瑞典 丹麦
A vocabulary
Argentina Switzerland Symbol Candy Italy 阿根廷 瑞士 象征,标志 糖果 意大利
A answers
1. Argentina A tie is too personal 2. Switzerland Roses mean love 2. Italy Even numbers(2,4,6,etc.) are unlucky 3. Japan Japanese people usually don’t give four of gift.
B vocabulary
Bow Greet Asian Russia Brazil Abraco Firm Egypt 鞠躬 问候 亚洲的 俄国的 巴西 拥抱 坚硬的 埃及
B answers
1. 2. 3. 4. A bow: Japan, Korea a hug: Brazil, Russia a strong, short handshake: Canada, the U.S. a softer, longer handshake: Egypt, Mexico
C vocabulary
相关文档
最新文档