identity based encryption-Private key
How are private keys handed to users in Identity-based Encryption?
Add folder name to beginning of filename Reducing Lion OS Footprint by removing unnecessary files/folders I am trying to downsize my iMac 640Gb disk to make it fit onto a 120Gb (113Gb usable) SSD.  The total size of use files is currently approximately 340Gb, of which my home folder accounts for 265Gb (which I intend to not put on the SSD, or at least not all of it).  Very rough calculations suggest that my OS and application files are taking up roughly 75Gb, which puts me approximately 2/3rds full - not bad.  But, I would like to reduce this a little further if possible, to ensure that as and when I continue to use the computer (and I have a number of large apps that do not currently have installed including music production apps with a lot of data) I am not worried about running out of space on the boot drive.  To this end I already own XSlimmer which I will use periodically to remove PowerPC and language variants from my apps, but I was wondering if there are any areas of the Base OS that I can safely remove to save further space?  I am thinking about things like OS localisation, the location of the included screensavers and wallpapers, the voice files that are used for text-to-speech etc.  Is there a significant amount of such data that can be easily removed to save a few extra Gb on the boot disk? If $x^n=y^n$ and $n$ is odd then $x=y$ Here, we suppose that $x,y\in\mathbb{R}$ and that $x^n=y^n$, where $n$ is odd. I want to prove that $x=y$.  Maybe we can use that $x^n-y^n=(x-y)(x^{n-1}+x^{n-2}y+...+xy^{n-2}+y^{n-1})$  So, it suffices to show that if $x^n=y^n$ then $x^{n-1}+x^{n-2}y+...+xy^{n-2}+y^{n-1}\neq 0$  Any hint? How should "do my homework" questions be closed? (Missing "demonstrate minimal understanding") Just recently,  question was posted. Here's the body of the question:     Write a function called highlight() that prompts the user for a string. Your code should ensure that the string is all lower case. Next, prompt the user for a smaller 'substring' of one or more characters. Then replace every occurrence of the substring in the first string with an upper case. Finally, report to the user how many changes were made (i.e., how many occurrences of the substring there were).      What would a script for this be?   This is basically a "do my homework for me" style question. In the past, I would have voted to close this question for lacking minimal understanding and moved on. However, it looks like this close reason was removed, and I'm having difficulty figuring out which alternative to use (if at all).  Here were some of the close reasons I was considering, and ultimately decided against since they didn't seem to precisely match:   Duplicate of    I sort of doubt there exists a precise duplicate of this question -- the question is a fairly specific request for some code. I could maybe link to a duplicate question that answers a part of the original (for example, checking if the string is lowercase), but it wouldn't answer every aspect of the problem. Problem that can't be reproduced/typographical error    This sort of matches, since it asks the user to produce a SSCCEE, but doesn't really match since there isn't even a problem to begin with (and closing a question because I couldn't "reproduce" a non-existent problem feels a bit silly to me) Unclear what you're asking    It's pretty obvious what the user is asking -- I could produce a 5 line script in about 20 seconds that precisely matches his spec. Too broad    The text for "Too broad" states that "There are either too many possible answers, or good answers would be too long for this format". This doesn't apply to this question -- once again, the answer I could give would be fairly short and would closely resemble solutions other people would give.   So, what should I do here? Am I misunderstanding how the close reasons should now be used? Should I use the "other" close reason and explain that the OP should have put in more effort? Should I simply downvote, perhaps leave a comment, and move on? Or is the new policy to embrace these kinds of questions and just post an answer? How to restore file copy / transfer status window? Is it possible for information to be transmitted faster than light by using a rigid pole? Is it possible for information (like 1 and 0s) to be transmitted faster than light?   For instance, take a rigid pole of several AU in length. Now say you have a person on each end, and one of them starts pulling and pushing on his/her end.   The person on the opposite end should receive the pushes and pulls instantaneously as no particle is making the full journey.  Would this actually work? Modus Operandi. Formulae for Maximum and Minimum of two numbers with a + b and $|a - b|$ I came across the following problem in my self-study of real analysis:     For any real numbers $a$ and $b$, show that $$\max \{a,b \} = \frac{1}{2}(a+b+|a-b|)$$ and $$\min\{a,b \} = \frac{1}{2}(a+b-|a-b|)$$   So $a \geq b$ iff $a-b \ge0$ and $b \ge a$ iff $b-a \ge 0$. At first glance, it seems like an average of distances. For the first case, go to the point $a+b$, add $|a-b|$ and divide by $2$. Similarly with the second case.   Would you just break it up in cases and verify the formulas? Or do you actually need to come up with the formulas? Proof that the One-Dimensional Simple Harmonic Oscillator is Non-Degenerate? The standard treatment of the one-dimensional  (SHO) using the raising and lowering operators arrives at the countable basis of eigenstates $\{\vert n \rangle\}_{n = 0}^{\infty}$ each with corresponding eigenvalue $E_n = \omega \left(n + \frac{1}{2}\right)$. Refer to this construction as the abstract solution.  How does the abstract solution also prove uniqueness? Why is there only one unique sequence of countable eigenstates? In particular, can one prove the state $\vert 0\rangle$ is the unique ground state without resorting to coordinate representation? (It would then follow that the set $\{\vert n \rangle\}_{n = 0}^{\infty}$ is also unique.)  The uniqueness condition is obvious if one solves the problem in coordinate representation since then one works in the realm of differential equations where uniqueness theorems abound. Most textbooks ignore this detail (especially since they often solve the problem both in coordinate representation and abstractly), however I have found two exceptions:   Shankar appeals to a theorem which proves one-dimensional systems are non-degenerate, however this is unsatisfactory for two reasons:   Not every one-dimensional system is non-degenerate, however a general result can be proven for a large class of potentials (the SHO potential is in such a class). The proof requires a departure from the abstract solution since it classifies the potentials according to their functional properties.  Griffiths addresses this concern in a footnote stating that the equation $a \vert 0\rangle = 0$ uniquely determines the state $\vert 0\rangle$. Perhaps this follows from the abstract solution, however I do not see how. Debian users have a kind of "wayback machine":  , which is really great.  There are regressions sometimes, and if I don't have local deb package with old version, I'm getting sad sometimes. Having a wayback machine like this is very helpful.  I can't find analogue of it for Ubuntu. Have I missed it? Just like if we have any quadratic equation which has complex roots, then we are not able to factorize it easily. So we apply quadratic formula and get the roots.  Similarly if we have a cubic equation which has two complex roots (which we know conjugate of each other) and one fractional root, then we are not able to find its first root by hit &amp; trial.  So my question is like quadratic formula, is there exist any thing like cubic formula which help in solving cubic equations?  For example, I have an equation $$2x^3+9x^2+9x-7=0\tag{1}$$ and I have to find its solution which I am not able to find because it has no integral solution. Its solutions are $\dfrac {1}{2}$, $\dfrac{-5\pm \sqrt{3}i}{2} $, I know these solutions because this equation is generated by myself.  So how can I solve equations like these?  Also while typing this question, I thought about the derivation of quadratic formula, which is derived by completing the square method.  So I tried to apply ‘completing the cube’ method on the general equation $ax^3+bx^2+cx+d=0$ but it didn't help.  So please help me in finding a cubic formula or to solve the equations like given in example by an alternative method. How do I reset a lost password (using recovery mode requires me to type the password)? I need to reset my password. I have followed these steps:    However, then I go to "root" or "netroot" recovery options, it tells me:  Give root password for maintenance (or type Control-D to continue)   Clearly, I do not know the root password. If I type CTRL+D, I return to the list of options. From  I read:  Under chapter 'The Other Way':  4. Highlight the line that begins kernel and press 'e' to edit`   But in the grub configuration file I have no line that starts with kernel. Only:  setparams 'Ubuntu...' recordfail set gxfpayload... insmod part_msdos insmod ext2 set root=... search --no-floppy... linux /boot/vmlinuz-2.6.38... initrd /boot/initrd.img-2.6....   Those are all lines in my GRUB. Which line should I edit? Or is there another way to reset my password? Is there any freely available pointcloud data?   I'm especially interested in dense clouds of small areas(5m to 100m radius) but anything else would be fine too.   I've found that these pages have very nice and easy to access point cloud data. Skyrim - Companions attacked me for no reason? How to tell whether two graphs are isomorphic? How small does a land-mass have to be before you live "on" it, rather than "in" it? I'm sure virtually everyone agrees that people live on the Isle of Wight, but in Ireland.  Apparently the usage depends somewhat on physical size, but that can't be the whole story. How exactly do we decide which form to use? And are there any really glaring 'outliers' that don't fit the normal pattern?  LATER - I must just add that the most uncertain case I've found so far is The Falklands. Most people go for in there, but a substantial minority (about 1 in 3) opt for on. Why is the \bf command applied to more than I asked? MWE:  \documentclass{article}  \usepackage{bm}  \begin{document} $$x(t), \bf{x}(t), \bf{x(t)}$$ \end{document}   Result:    Question:  Why are the second and third x(t) typeset the same? In the second  expression, it was asked to apply \bf to only x.  EDIT:  I had not payed attention to it when asking the question, but I would like to have a bold and italic x. How do I change a close vote to a duplicate? Voted to close a question based on "lack of minimal understanding".  Later realized the question was a duplicate.  How to I change vote to mark as duplicate instead? Why is my voice command missing from the ok glass menu in XE16? If $A|B$ and $B|A$ then prove $A=\pm B$ If $A|B$ and $B|A$ then prove $A=\pm B$   So far I have $A|B \iff AX=B$ and $B|A \iff BY=A$ with $X,Y \in \mathbb{Z}$  Not sure how to finish, any help. UITextField - capture return button event