computer science

Qihoo 360

Qihoo 360 is a computer science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Qihoo 360 rather than just read about it. In short: 360 Security Technology Inc., also branded as Qihoo 360 (CHEE-hoo, 奇虎 qíhǔ), is a Chinese internet security company that has developed the antivirus software programs 360 Safeguard and 360 Mobile Safe, the Web browser 360 Secure Browser, and the mobile application store 360 Mobile Assistant. It was founded by Zhou Hongyi and Qi Xiangdong in June 2005.

Key takeaways

Qihoo 360 belongs to computer science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Qihoo 360 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Qihoo 360 from memory before moving on to harder problems.

Reference excerpt

360 Security Technology Inc., also branded as Qihoo 360 (CHEE-hoo, 奇虎 qíhǔ), is a Chinese internet security company that has developed the antivirus software programs 360 Safeguard and 360 Mobile Safe, the Web browser 360 Secure Browser, and the mobile application store 360 Mobile Assistant. It was founded by Zhou Hongyi and Qi Xiangdong in June 2005. The company's head office is in Chaoyang, Beijing.

History In the summer of 2012, Qihoo 360 entered the smartphone market by launching the Battleship phone together with the large Chinese electronics company Haier. Qihoo 360 stated that Haier will provide the hardware while Qihoo 360 will focus on customising the software, albeit the main operating system will be Android. Qihoo 360 received over 220,000 pre-orders for the phone the first day. Later in 2012, Qihoo 360 launched the search engine so.com, thereby directly competing with Baidu, the most prominent search engine in China. Qihoo's share of unique visitors grew to 10.52% of the total search engine market in China. At the end of July 2013, Qihoo was in early talks to acquire Sohu.com’s Sogou.com search engine for around $1.4 billion. In early 2015, Qihoo rebranded its so.com search engine as haosou.com. "Hao" in Chinese means good; Haosou directly translated to English means "good search engine". In December 2013, the company increased its stake in the Brazilian tech company PSafe. On July 11, 2014, the company set up a venture capital fund in Silicon Valley. On December 18, 2015, Qihoo 360 agreed to be acquired by a group of investors in a deal valued at about $9.3 billion. On July 18, 2016, Qihoo 360 bought most of Opera Software for US$600 million. In 2018, Qihoo 360 invested in Shanghai-based i-Soon. In June 2026, at the ISC.AI 2026 cybersecurity conference in Beijing, founder Zhou Hongyi unveiled two AI security tools under the banner "Yitian Tulong": Tulongfeng, an automated software-vulnerability discovery system that the company described as China's answer to Anthropic's Mythos model, and Yitianzhen, a system for automating cyber defence and incident response. The company said Tulongfeng had found 3,432 software vulnerabilities, 105 of them confirmed by Chinese authorities. Cybersecurity researcher Alan Woodward of the University of Surrey commented that the system might not match Mythos but that its emergence showed such tools were likely to proliferate regardless.

U.S. sanctions

In May 2020, Qihoo 360 and other Chinese companies were placed on the Bureau of Industry and Security's Entity List due to U.S. national security concerns. The U.S. accused Qihoo 360 and others of playing roles in the crackdown in Xinjiang by "enabling China’s high-technology surveillance" in Xinjiang. On 25 May, Chinese Foreign Ministry spokesman Zhao Lijian strongly criticized the step, asking the US to "revoke the relevant decision and stop interfering in China’s internal affairs". In October 2022, the United States Department of Defense added Qihoo 360 to a list of "Chinese military companies" operating in the U.S.

Controversies

Lawsuits Qihoo has been described by Forbes as a confrontational and litigious company due to its involvement in various anti-competition lawsuits. The company was involved in lawsuits with Tencent, starting with the 360 v. Tencent dispute, as well as other companies such as Baidu, Emiage, and Sogou.

Traffic data The company has been accused by Anonymous of overstating the volume of traffic to its site to attract advertisers.

Antivirus test results The antivirus testing companies AV-Comparatives of Austria, Germany's AV-Test, and Virus Bulletin of the UK have accused Qihoo of providing for testing its anti-virus equipped with a Bitdefender engine, while the consumer version uses Qihoo's own QVM engine.

Certificates According to documents released by the Mozilla Corporation in 2016, Qihoo appears to have acquired a controlling interest in the previously Israeli-run Certificate Authority "StartCom", through a chain of acquisitions, including the Chinese-owned company WoSign. WoSign also has a certificate authority business; WoSign has been accused of poor control and of misissuing certificates. Furthermore, Mozilla alleges that WoSign and StartCom violate their obligations as Certificate Authorities in respect of their failure to disclose the change in ownership of StartCom; Mozilla is threatening to take action, to protect their users. Google have stated that their Chrome product will no longer trust by default any certificates signed by StartCom or Wosign roots, starting with Chrome 61. Mozilla have stated that their Firefox product will no longer trust by default any certificates signed by StartCom or WoSign roots, starting with Firefox version 58.

Hidden backdoors

In 2012, a whistleblower reported a hidden backdoor in 360 Secure Browser. The Product Director of 360 Secure Browser, Tao Weihua, responded that "Whoever has a mind to beat a dog will always be able to find a stick" and accused the whistleblower of "smearing 360 on behalf of Baidu", which the whistleblower said was "the worst professional response in history". Independent analysis of the claim showed that the browser has an "undeclared mechanism (i.e., via ExtSmartWiz.dll) which regularly connects to the server (e.g., every 5 minutes), and allows it to download files of any type (including executables) from the server." In October 2020, Mnemonic reported the existence of a backdoor affecting a line of children's watches under the Xplora brand manufactured by Qihoo.

Samsung device cleaner In January 2020, a Reddit user reported Qihoo's presence in Samsung mobile phones as a pre-installed storage cleaner in the device settings, from where it sends data packages to Chinese servers. The user could not identify which information is sent specifically. Later, Samsung representative declared that the only data sent back to Qihoo is generic information needed to optimize storage — specifically naming OS version, phone model, and storage capacity, among other data. Qihoo's main contribution is a reference library for identifying junk files, but that library is stored locally in the utility, and Qihoo never receives data that would allow it to identify a particular file on a user's device.

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Qihoo 360

Start with the simplest possible case. Write down what Qihoo 360 claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In computer science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Qihoo 360 before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Qihoo 360 ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Qihoo 360

In research: Qihoo 360 appears in computer science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Qihoo 360 in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Qihoo 360 is common in secondary-school and first-year university syllabi. It links to neighbouring topics 2005 establishments in Beijing, 2011 initial public offerings, 2016 mergers and acquisitions, so understanding it makes those chapters shorter.
In everyday life: Look for Qihoo 360 outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

Ask Teacher Smith questions about this articleOpens your AI tutor with a question about “Qihoo 360” →

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study Qihoo 360 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Qihoo 360 means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Qihoo 360 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Qihoo 360 in simple terms?

Why does Qihoo 360 matter?

Because it connects several computer science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Qihoo 360?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Qihoo 360.