I have 2 questions regarding security issues related to initialization vectors used in AES CBC   Consider that I'm using a sequence number (which increments with every encryption) as an initialization vector. Would this be a security issue? Is there some way that an attacker who knows the sequence numbers and in turn knows the IV, be able to decrypt even some part of the data, if not the whole?    I'm asking this question because some of the comments on the 1st answer in the following link seem to suggest that using a counter for an IV would not be a good choice.   If it is possible to perform such an attack, can you provide an explanation of how this would be possible? I tried searching. But, none of the sources I found seem to answer why the IV cannot take values from a counter. They only talk about safety in terms of storage.   The other question is related to transmission of IVs. I searched quite a bit and everyone says that the IV need not be secret. But, if IV is exposed, isn't it possible for a man in the middle to change the IV so that the end result at the decryption end will fail?
I just learned that using CBC encryption with an IV which is predictable is not secure.  From what I understand, using certain plain texts, and then guessing the IV that it uses, the attacker can verify if the IV he guessed was right. How does this qualify as an attack?
Is there any way to tell Google to use a particular account for all Google services by default? I typically use 2 Google accounts simultaneously in my browser. So whenever I fire up any Google service like Google Maps or YouTube or Google Search, it uses one of the accounts. The problem is that I don't want that account to be used and no matter how many times I switch the account for these services, they seem to default to same account.  Is there any way to tell Google to use a particular account for all Google services by default?    I am not talking about using Google account to sign in to third party websites. I am talking only about Google's own services.  I am using Chrome if anyone is going to suggest client-side solution. How is the skillset of an evolution being chosen? You may already know that if you catch two Pidgeys, they may have a different skillset.  I've also seen that evolving them from different skillsets will also create Pidgeottos with different skillsets.  Are those skills chosen randomly or do they follow a specific pattern? (Like Pidgey pattern 1 will always evolve into Pidgeotto pattern 1.)  If they are specific, is there a website to check for them? Change equation font in Pages During a Pages update which was pushed out a few months ago, Pages obtained the ability to write equations using LaTeX or MathML commands. According to an Apple Support article, the size and color of the equation can be changed ():  The equation appears at the insertion point in your document (or before the selected text). The equation is an inline object, the same size and color as the surrounding text. If you change the size or color of the surrounding text, the size and color of the equation’s font also change.  This does not mention anything about the font used for the equation itself, which seems to be something similar to a Times New Roman font. Is there any way to change the font used, preferably to something like Latin Modern Math? I was considering the possibility of replacing the font file Pages uses with a downloaded Latin Modern Math font file, but I'm not sure what to replace. Could I replace Times New Roman in /System/Library/Fonts/ or something like that? Explain briefly What is meant by interpolation.How is it related to the concept of regression?  interpolation is art of reading between the lines of a table and in elementary mathematics the term usually denotes the process of computing the intermediate values of a function from a set of given or tabular values of that function.  I can't give the answer of second question. The MathJax code in Mathematics Stack Exchange doesn't render after I updated to the new version (It used to):     App Version: 1.6.2.5 Device: iPhone 6s OS Version: Version 9.0 (Build 13A342) Can a union be initialized in the declaration? In the Phone app (iPhone 5, iOS 6.1.2), I click on a contact's number, the call is initiated and starts ringing.   For a brief moment at this point, the label of the number (home / work / etc…) is displayed alongside the contact's name, but it quickly is removed and replaced with the call timer counting up and only the name (and picture of the contact) are shown.      How can I see the number that is being called during a phone call? How can I remove malicious spyware, malware, adware, viruses, trojans or rootkits from my PC? What should I do if my Windows computer seems to be infected with a virus or malware?  What are the symptoms of an infection? What should I do after noticing an infection? What can I do to get rid of it? how to prevent from infection by malware?   This question comes up frequently, and the suggested solutions are usually the same. This community wiki is an attempt to serve as the definitive, most comprehensive answer possible. Feel free to add your contributions via edits. Inequality involving $\limsup$ and $\liminf$: $ \liminf(a_{n+1}/a_n) \le \liminf((a_n)^{(1/n)}) \le \limsup((a_n)^{(1/n)}) \le \limsup(a_{n+1}/a_n)$ Create violine plots I use pgfplots for most of my plots. Now I need to add a . Is this possible with pgfplots or any other package? Manually clear saved question drafts I've seen lately that new question editing is stored somewhere for later use if we wander off the new question without posting it and then return back to the page. Which is a good functionality addition in it's own right.  What I'd like to also have is the Discard this draft functionality that would clear form data and forget it. Somehow we find an answer in the meantime and the question isn't valid any more.  So having a Discard saved draft or something similar would be a nice contra-functionality to auto-save to remove stored data. The way it's implemented now seems too hidden hidden and unpredictable to users.  Additional edit  When adding hidden auto functionality usually means creating the opposite as well by either giving the possibility to preference of not having automatism at all or giving the possibility to clear what's been auto saved.  Let's see how GMail doesn't work (and I think we all agree that from UX perspective it does the job as expected:   User clicks Compose message User starts writing a new email message User decides to not send the message and checks their inbox User clicks Compose message again A clean form is presented to user (old one being part of drafts)   I'm not suggesting we should have something like Saved drafts but we surely should have the possibility to clear previous question draft.  Since this new functionality was introduced I should point out that I would use the discard functionality more frequently than the saved one. I do welcome saving messages, but discarding of saved drafts is anything but a rare situation one might want to do. It wouldn't be a problem if this was a 1% against 99%. To me it's more like 50/50.  Best possible solution  When providing saved drafts there should (from the UX perspective) be the opposite functionality as well. Namely discarding of it. But first thing we should be asking ourselves is:    do users more frequently need pre-filled saved question draft or do users more frequently need empty form with the possibility to populate it with a saved draft   User testing should provide the usage frequency between the two and the one that's more likely to happen (my guess is that there would be a big difference between the two) should be implemented. So one of these:   Pre-populate question fields with saved draft on question form load, while also providing a button to clear the draft and start writing anew without the need to manually clear all the fields (which would be the optimal solution in case of a single field form) Question form should always load empty while also having a button that would pre-populate it with a saved draft.   I think this would be the best consensus related to saved question drafts and their usage. But as we've seen this issue has been swept under the rug for an indefinite time. Sometimes, when I upgrade a system via do-release-upgrade, the update process fails and the script tells me to finish the process manually via dpkg --configure -a. This is a not serious problem - after manually solving the dependencies problem and the finishing upgrade process all works well.  But the do-release-upgrade script has a cleanup process after finishing the upgrade:  Remove obsolete packages?   XXX packages are going to be removed.   Continue [yN]  Details [d]y   which removes some obsolete packages from old version of system.  Seems that this process doesn't execute when the automatic upgrade fails and I finish upgrade manually, so obsolete packages from old version remain installed in the system.  How I can run the "Remove obsolete packages" process manually after finishing the upgrade by hand? Is there a practical gain from elliptical/oval chainrings? I have seen competitive (amateur) cyclists with oval chainrings (front). What is the deal? Are they just for showing off, or is there a practical gain from it (different force transfer). How to tell whether two graphs are isomorphic? If tenured staff are virtually unsackable, why is the drive to find funding so strong? Sql Server string to date conversion I want to convert a string like this:  '10/15/2008 10:06:32 PM'   into the equivalent DATETIME value in Sql Server.  In Oracle, I would say this:  TO_DATE('10/15/2008 10:06:32 PM','MM/DD/YYYY HH:MI:SS AM')    implies that I must parse the string into one of the , and then convert using one of those codes.  That seems ludicrous for such a mundane operation.  Is there an easier way? Childrens fantasy, blind monk leading boy who can control the elements Product of square of distances from vertices of a polygon of radius a I want to find out the following product.  $\prod_0^{n-1}  (r^2 + a^2 -2ra\cos(2k\pi/n - \theta))$ I have been trying to use complex numbers but did not work out. The book I am reading the result is directly stated as $r^{2n} + a^{2n} -2r^na^n\cos(\theta)$. Please help. Finding the search terms behind 'not provided' We use Google Analytics to track the vistors to our websites, were currently putting together a big audit of our SEO and one of the things we want to see is what search terms are working for us.  About 90% of our organic search traffic comes under 'not provided' which as i understand means a user is signed into a Google account when coming to our site, thus Google doesn't track their search terms.   This makes it really hard to conduct a meaningful study, (i suppose we could get the data of the 10% that we do have search terms for and multiply them it but i dont think thats a particularly good or meaningful approach).  Is there a workaround to see behind the 'not provided' data and see the search terms actually used ?    UPDATE  I read  last night from Hacker news, which states :     [using https will allow you] more complete referrer information in Google Analytics for people   visiting from sites already using HTTPS   and contained a link to this , it seems to say that because Google's users are using https that an https site cannot pass data to an http site, as the http site is not secure, none of the sites i manage have https / sll setup, could some one confirm if Google will pass you more referrer data if your site has https implemented ? sometimes when writing mathematical expression with partial derivatives, one needs to write a vertical bar afterwards and write the value at the which the partial derivatives are being computed as subscripts. See for example the bottom post here:    However, the \mid symbol doesn't produce a tall bar that corresponds to the size of the partial derivatives term. Is there a way to have a taller bar?   PS: Some other posts here mention \middle| but this doesn't compile on my computer.  Thanks in advance....