Is it legal to crack MD5 hashes? I saw a website that involves programming problems. One problem asks to write a program that finds a string whose MD5 hash is given. Is it criminal to crack the MD5 hash by finding those strings?
Is it criminal to find strings whose MD5 hash is known? No, unless the method or purpose involves gaining (or attempting to obtain) unauthorized access to others' computer systems or networks, or causing damage to them. This applies regardless of whether you program some brute-force algorithm rather or query a public [online] database that stores reverse hashes.
So I can block children under 13, but I can't tell them that? You can tell them after they fail, you cannot tell them on the asking screen. Then what is the correct way to block children under 13 to access my website and still comply with COPPA? I agree with you that it is odd that they recommend using a cookie but they do!* So you have a entry page with a simple question, "Please indicate your age" and then block based on the response. That's it. Note that the rule is neutral. This means that you do not need to disguise your purpose or try to trick people into entering their correct age. *I think that what is happening here is that any parent who wants to complain to their legislator can be met with the response, "If your kid is so sneaky that they are using different computers to lie about their age what do you want us to do about it?" The fact is, this scheme keeps innocent kids from seeing stuff they shouldn't; the sneaky ones are going to find a way.
There are no such laws that are specific to rape, but there are general laws about false statements. In every state there is some law against making a false statement to a government official, e.g. Washington RCW 9A.76.175 which says that one who "knowingly makes a false or misleading material statement to a public servant is guilty of a gross misdemeanor". To shift context slightly, if you report to the police that Smith stole your lawn mower when in fact you gave it to him, that is a false statement. However, there would have to be clear proof that you lied in your report, and not that there was a misunderstanding. If Smith stole the mower but the evidence did not support a theft conviction, that does not mean that you can be prosecuted for making a false statement (whereas, if someone has a video of you telling Smith "Here's a mower, which I give to you because I like you", then you could almost be prosecuted for making a false statement, were it not for the fact that the video is illegal in Washington). Perjury is the other related crime: RCW 9A.72.020 "a materially false statement which he or she knows to be false under an oath required or authorized by law". [Addendum] About the video of the mower being given away... Washington is an all-party consent state, meaning that you can't just record people, you have to have their permission (everybody's permission). RCW 9.73.050 says that information obtained by illegal recording shall be inadmissible in any civil or criminal case in all courts of general or limited jurisdiction in this state, except with the permission of the person whose rights have been violated in an action brought for damages under the provisions of RCW 9.73.030 through 9.73.080 which is to say, "unless the person(s) who did not give permission to be recorded now give permission for the evidence to be admitted". Since "you" would be the one making a false statement, "you" would have an interest in suppressing the video, thus "you" could withhold permission for the video to be introduced.
If it was something important to the owner, they would file injunctions/suits against everybody that they find the code in, and make those very public. This isn't unlike what the RIAA did to individual downloaders of pirated music files, filing over 18,000 lawsuits. They could subpoena GitHub for information related to IP addresses for who downloaded the code and go after them. It is unlikely that they would get a financial award but they could have the court order them to stop using it. Eventually the RIAA found that filing these lawsuits was more trouble than it was worth and started going after the internet service providers. These reduced the number of lawsuits and forced ISP's to moderate its own users, blocking some sites and protocols that programs like Napster relied on. Basically they shifted responsibility from themselves to the ISP's.
Content posted to the web is usually openly accessible to all (unless protected by a password, paywall, or similar restriction). But that does not mean it is freely copyable by all. Such content is protected by copyright in just the same way as if it had been published in a book of essays by various contributors. Unless the copyright holders (who are likely to be the original authors, but might not be) give permission, or an exception to copyright applies, copying such content would be clear and obvious copyright infringement, and any copyright holder could sue for damages. Permission could be given by publishing the content under a permissive license, such as a CC-BY-SA license, or any of many other available permissive licenses. Or a would-be reuser could find the copyright holders and ask for permission. If the holder cannot be found or identified, or does not respond, then no permission has been granted. In the US the main exception to copyright is fair use. See this answer and other threads with the fair-use tag here for more on fair use. Since the question seems to contemplate using the whole of the posted content, since it might well damage any potential market for that content, and since the use does not seem to be &quot;transformative&quot;, nor used for criticism or comment, a finding of fair use for this situation seems unlikely. But Fair use findings are very much fact-driven, and the exact facts do matter. Thus I cannot be at all sure whether a court would find this toi be fair use or not. In other countries there are a variety of exceptions to copyright, and I have not come close to reviewing them all. But none of the ones I know of seem to apply to the situation described in the question. Many are narrower than the US concept of fair use. I fear that without permission, copying this content would be infringement. However, it would not be infringement to create a site that includes a link to the existing content, and a summary or description of that content, along with new content, including comments on the old, with brief quotes to indicate what is being commented on.
It is, in most jurisdictions, not a crime to download YouTube videos. For criminal law, the answer is that it is not illegal. In many jurisdictions, downloading music or video of any kind from the internet is not a crime. Thus, police has no power to punish you for downloading, and even less power to shutdown such "downloader" websites. YouTube's Terms of Service seem to disallow such downloads so YouTube has the right to terminate the agreement with the downloader. They may prevent you from viewing any more videos, for example. However, I think Google does not even have a technical measure in place to do that. Google is not interested in preventing you from using YouTube (its servers can handle that) and that is pretty much the only punishment it can use. Google could use the Terms of Services to say that the downloader-websites are breaking them and thus should not have access to YouTube. The websites could be sued for breaking the Terms of Services (and the court could order them to stop) and Google can block those websites from accessing YouTube by technical measures. It appears it did so in at least one case. Google could sue you (or the websites) for advertisement revenue loss, but it is unlikely. In theory, Google loses advertisement revenue from the video playbacks you would have done on YouTube but did not play because you downloaded the video and played it offline (contrary to the Terms of Service). Google might attempt to sue a downloader website on this basis and try to make it give it money. It would be difficult for Google to prove that it deserves such money, though. I cannot imagine how it would prove that "you would have played the video online, again, with advertisements, if you didn't download it. Note that when you replay a video from browser cache, advertisements do not replay. Why Google doesn't sue downloader-website more often? It's expensive. Google could pay a lot of money to shut down a website via court order but if it really wants to do so, they can apply a technical measure (such as IP block) instead. It is much cheaper and has the same effect. This may change in the near future. There's a some talk around about European court rulings and directives that may change this. It is quite possible that in the near future, even viewing illegally uploaded music on YouTube will be criminal. I find this doubtful because of the difficulty of proving knowledge ("How was I supposed to know that it wasn't an official clip?"). As for whether downloading to a file (as opposed to downloading to the browser cache) will become criminal, I really doubt that.
Yes and no. [note, the following is all written about US law. In other jurisdictions laws are, of course, different (though usually not drastically so.)] In the US there are (at least) three different bodies of law that might apply to code: copyright, patents, trade secrets. Copyright covers original expression. Anything you write is automatically, immediately protected under copyright. The copyright applies to the code itself, and anything "derived" from that code. It's up to the courts to decide exactly what "derived" means. One case that's long been viewed as a landmark in this area is Gates Rubber v. Bando Chemicals. The Court of Appeals for the tenth Circuit decision includes a section titled: "The Test for Determining Whether the Copyright of a Computer Program Has Been Infringed." Note that you can register a copyright, and that can be worthwhile, such as helping recover some damages you can't otherwise. Patents are quite different from copyrights. Where a copyright covers expression of an idea, a patent covers a specific invention. Rather than being awarded automatically, a patent has to be applied for, and awarded only after the patent office has determined that there's no relevant prior art to prevent it from being awarded. A patent, however, covers things like somebody else independently discovering/inventing what's covered by the patent. A trade secret could (at least theoretically) apply to some process or procedure embodied in the code. A trade secret mostly applies to a situation where (for example) you're trying to form an alliance with some other company, and in the process tell them things you don't tell the general public. If you've identified the fact that what you're telling them is a trade secret, and they then tell a competitor (or the general public, etc.) or more generally use that information in any way other than the originally intended purpose, it could constitute a trade secret violation. As a side-note: patents and copyright fall under federal law, so they're basically uniform nation-wide. Trade secrets mostly fall under state law, so the exact details vary by state. Absent a reason to believe otherwise, I'd guess your interest here is primarily in copyright infringement. The key here would be showing that one piece of code was derived from the other. That is, it specifically would not apply in a case where there were only a limited number of ways of doing something, so anybody who wanted to do that had to use one of those ways. Since this would not indicate actual derivation, it would not indicate copyright violation.
Unless there is a law or regulation against it, it is legal. However in a big government it can be practically impossible to determine whether something is legal. For example, nobody even knows how many criminal statutes have been promulgated by the U.S. federal government. And that's nothing compared to the volume of executive regulation and judicial case-law that determines whether something is illegal. I.e., in practice determining that something is legal is a bit like proving a negative. Furthermore, if you look long enough some argue that you can probably find some law under which almost any action could be considered illegal. Note also that even if it is not against the law, it could be proscribed by contract (read your Terms and Conditions!), and breach of contract is in general &ndash; but with an astonishing number of exceptions! &ndash; illegal.