Assignment for Feb.24

LAMP, stands for:
Linux, the operating system
Apache, the web server
MySQL, the database server
PHP\Perl\Phthon the programming languages

People like the combination of these because they are all open source. And they work pretty well together for building applications especially web applications.

Assignment 2 for Feb 10.

I think there are to reasons for the citizenship for us is quite obvious. Since we are a part in the community, we are responsible to do our work for it (or is that only because I grew up in a Communism county) . After we graduate we will be a essential part or the society and we should play our roll to make it run well.

Even if this is not like a moral rule, it is still quite useful to learn about this. When we go to work, we will face a lot of similar situations as we do during Service Learning, and real experience is the most precious thing for us. College should not only teach us academics but also some real thing we can make use immediately. So I think it is meaningful to have these courses.

Assignment 1 for Feb 10.

Google does a difficult job. It is a company born for the information Age. "Meanwhile, here's Google, which is using the information it collects to build better services that we eagerly consume because they are useful to us"- Tim O'Relly, CEO of O'Reilly Media. Since it is new, if there is a conflict between providing information and keeping information private, there is no rule to follow. Moreover, it is hard to identify the information, which one is all right for some guy, which one is not.

According to the law in any country, there is no way to disallow any one to take any pictures at public places and uploading it on his/her blog or something. The only reason for people concerning about Google is because it is too popular. Too many people would see it, it if is on Google. And sometimes people don't want to be seen by the whole world, especially when they are just coming out from a "Adult Book Store" or something else; or sometimes being caught by friends saying "Hey, you are on Google". However, most of the people don't care or don't even realize fi they are on Google or not. And, for sure, most of the pictures are just regular ones.

In the fact, Google seems to think more about privacy (e.g. at the year year when the DOJ tried to get access to users’ queries, and Google was the only company out of 30+ that said “no” and went to court about it — and won).

In this case, Google also offers a "help" button on all the street-level photos to provide a link for users to request the removal of an image that is objectionable or clearly identifies a person who doesn't want to be included in the visual tapestry. However, company spokeswoman Victoria Grand said Google has fielded "very few" removal requests so far -Michael Liedtke, Associated Press.

In my opinion, it is not a big deal of those photos, it might be for some one, but they have the choice to tell Google the case.

Assignment 2

After I have finished my undergraduate degree I'm pretty sure I will work on a master degree. After that, which might be 4 years later, I think I am going to work for a couple of years, maybe in the States maybe back in China, probably as a software engineer. Then I think I will try to run my own company in China, after I have this experiences. That is my dream and I already have some friends who have this same goal. To reach this goal, I should not only focus on the technology part of software or hardware or something like that, the main issue for me to learn is how to manager a group, a team and a company as well. Which makes this course quite important for it tells me the social issue within this field. Which might be quite important.

Assignment 1

Symmetric keys are exchanged by private communications, such as through a private meeting or something similar. Once the key is distributed, it could be used multiple times,
but no one can change to another key anymore - Not until they meet another time.

Symmetric keys could only be cracked by trying all the possibilities of the keyspace, which often turns out to be very big. And even if the cracked tries out all the possible keys, it still may or may not generate multiple understandable meanings, which could confuse the cracker.

Since it is the same key used both on encryption and decryption, so the only one that can send a code which could be decrypted by the key in the receiver's hand, is the one that owns the same key(What a sentence!). In other words, only the ones that share keys can communicate.

The advantage of the symmetric key technique is that it is fast and safe. Increasing key space doesn't make many performance changes for the sender and receiver who owns the key. But it would be like impossible to crack a 256-bit keyspace. However, the key distributing may cost a lot, especially in the cases where the two objects don't need to communicate a lot of times. And communicating between strangers is also hard to fix in this method.

In the Asymmetric method, the public key can be know by everyone, it can be posted at public places, or mainpages, or everywhere possible. The private key is kept by oneself ,which doen't need to be distributed.

The security of cryptographic in this case is based on the well admitted assumption that it is hard to factor large numbers.

The only message that a public key can decrypt is the one that is encrypted by the owner of the private key. And it is same the other way, which provides the way to send messages and signature documents.

The advantage of asymmetric keys is that there is neither risk or cost by sharing public keys. And if we want, we can change our public key and private key at any time. Which is convenient for totally strangers. However, the encryption and decryption turned out to be much slower and the keys are also larger. And it is not safe enough in the "Man sit in the middle case".