A program that focuses on the design of technological information systems, including computing systems, as solutions to business and research data and communications support needs. Includes instruction in the principles of computer hardware and software components, algorithms, databases, telecommunications, user tactics, application testing, and human interface design.
Definition - What doesArtificial
Intelligence (AI)mean?
Artificial intelligence (AI) is an area of
computer science that emphasizes the creation of intelligent machines that work
and react like humans. Some of the activities computers with artificial
intelligence are designed for include speech recognition, learning, planning
and problem solving.
Learn one way to build applications with Angular and reuse your code and abilities to build apps for any deployment target. For web, mobile web, native mobile and native desktop.
These files are simply zipped files using java jar tool. These files are created for different purposes.
.jar files: The .jar files contain the group of .class files and libraries. .war files: The war file contains static resources i.e., html, js, css...etc and dynamic resources jsp, servlets etc and other files (web.xml) for necessary for the development of web applications. Combination of these files zipped in to one module called .War file. .ear files: The .ear file contains anything Java/J2EE (Enterprise) related files zipped in to one module called .ear file. It is deployed in Application server.
URL encoding stands for encoding certain characters in a URL by replacing them with one or more character that consist of the percent character “%“ followed by 2 hexadecimal digits. So URL encoding and decoding is used that a string conform to the the Uniform Resource Locators Specification – RFC 1738.
Class Loader is used to load classes and interfaces.
Types of class loader
Bootstrap class loader : This class loader is responsible for loading core java API classes like rt.jar . Bootstrap class loader is native implementation and so they may differ across different JVMs. Location :- jdk/jre/lib/rt.jar
NumberFormatis the abstract base class for all number formats. This class provides the interface for formatting and parsing numbers. NumberFormat also provides methods for determining which locales have number formats, and what their names are.
NumberFormat helps you to format and parse numbers for any locale. Your code can be completely independent of the locale conventions for decimal points, thousands-separators, or even the particular decimal digits used, or whether the number format is even decimal.
Binary Search: Search a sorted array by repeatedly dividing the search interval in half. Begin with an interval covering the whole array. If the value of the search key is less than the item in the middle of the interval, narrow the interval to the lower half. Otherwise narrow it to the upper half. Repeatedly check until the value is found or the interval is empty.
We basically ignore half of the elements just after one comparison.
Java is an object oriented language and can view everything as an object. A simple file can be treated as an object, an address of a system can be seen as an object.
"wrapper can be used to convert any data type into object"
The primitive data types are not object they do not belongs to any class they are defined in the language itself that's why Java is not
Main method in java is entry point for any core java program. Remember we are not talking about servlet, MIDlet or any other container based managed java program where life cycle method are provided to control the execution.
@Controller is used to mark classes as Spring MVC Controller (e.g. a web controller).
It is typically used in combination with annotated handler methods based on the RequestMapping annotation.
@ExceptionHandler
@ExceptionHandler works at the Controller level and it is only active for that particular Controller, not globally for the entire application.
HandlerExceptionResolver
This will resolve any exception thrown by the application. It is used to resolve standard Spring exceptions to their corresponding HTTP Status Codes. It does not have control over the body of the response, means it does not set anything to the body of the Response.It does map the status code on the response but the body is null.
@ControllerAdvice
@ControllerAdvice used for global error handling in the Spring MVC application.It also has full control over the body of the response and the status code.
Hyper Text Transfer Protocol Secure (HTTPS), which is the encrypted version of its predecessor HTTP. Both of these protocols are used to transfer data from a website's server to the browser on your computer, but when you try to connect to a website using HTTPS, your browser will first ask the web server to identify itself. Then the server will send its unique public key which is used by the browser to create and encrypt a session key. This session key is then sent back to the server which it decrypts with its private key. Now all data sent between the browser and server is encrypted for the remainder of the session. For example, a government could tell that a user is browsing Wikipedia, but couldn't tell that the user is specifically reading the page about Tiananmen Square.
Image: Wikimedia Commons/Shutterstock - Remix by Jason Koebler
Harvard researchers found fewer instances of Wikipedia censorship after the site started encrypting all of its traffic.
"Knowledge is power," as the old saying goes, so it's no surprise that Wikipedia—one of the largest repositories of general knowledge ever created—is a frequent target of government censorship around the world. In Turkey, Wikipedia articles about female genitals have been banned; Russia has censored articles about weed; in the UK, articles about German metal bands have been blocked; in China,
var page =require('webpage').create();//viewportSize being the actual size of the headless browser
page.viewportSize ={ width:1024, height:768};
page.open('http://github.com/',function(){
page.render('github.png');
phantom.exit();});
Autonomous cars have arrived. Major automakers have been investing billions in development, while tech players like Uber and Google’s parent company have been testing their versions in American cities.
How a Car Drives Itself
LIDAR UNIT
CAMERAS
Constantly spinning, it uses laser beams to generate a 360-degree image of the car’s surroundings.
Uses parallax from multiple
images to find the distance to
various objects. Cameras also
detect traffic lights and signs,
and help recognize moving
objects like pedestrians and
bicyclists.
RADAR SENSORS
Measure the distance from the car to obstacles.
MAIN COMPUTER
(LOCATED IN TRUNK)
ADDITIONAL
LIDAR UNITS
Analyzes data from the sensors, and compares its stored maps to assess current conditions.
By Guilbert Gates|Source: Google | Note: Car is a Lexus model modified by Google.
Raspberry Pi, the makers of those affordable single-board computers, and the CoderDojo Foundation, which runs a network of coding clubs for school-age children, have announced they’re merging in order to give more young people opportunities to get into compsci.
CoderDojo is a global phenomenon, with over 1,250 clubs spread across 69 countries. These are attended regularly by 35,000 young coding enthusiasts. Phillip Colligan, CEO of the Raspberry Pi foundation, says it wishes to increase these to 5,000 by 2020.
The CoderDojo will retain its status as an independent charity, registered in the Republic of Ireland. The curricula will also remain the same, and dojos will be able to teach kids coding using whatever tech they see fit, or have available.
But the merger — which is subject to approval by Irish regulators — will see the Raspberry Pi Foundation as a corporate member, as well as providing practical, financial, and back-office support. Colligan will join the CoderDojo foundation as a director.
Given the quality of computer science curriculum in many schools leaves a lot to be desired, it’s amazingly gratifying to see third-sector organizations like the Raspberry Pi Foundation and CoderDojo fill the gap. Both of these organizations have historically been very effective at introducing young people to computer science. This closer collaboration will only increase their efficacy.
You probably don’t always like/share/comment on the stuff that pops up in your Facebook feed, even if it’s something you care to see. Take, for example, a breaking news items about an earthquake on the other side of the world — you’d probably feel weird hitting a button labeled “Like” on that one, and you might not have anything to say… but that doesn’t mean you don’t care.
Realizing this, Facebook is tweaking its algorithms to account for a new metric: the amount of time you spend looking at things in your feed, regardless of whether or not you actively interact with it.
Scroll past something without stopping for long, and Facebook’s algorithms will slowly learn that you don’t particularly care for that sort of content.
Camp out on a post for a bit, though, and Facebook starts the timer behind the scenes. If you spend more time on this story than you spend on most things in your feed — studying a picture, perusing the comment thread — they’ll take that as a signal that it’s something you care about.
In other words: those endless baby photos and motivational fitness memes that you tend to scroll right on past? At least theoretically, this change allows Facebook’s algorithms to take the hint without requiring you to lift a finger.
It’ll be interesting/a little terrifying to see how this actually impacts what shows up in feeds, if only because it’s all so passive. Facebooks algorithm’s have thus far been largely tuned by what you’re liking/sharing/commenting on — actions that all require at least a modicum of conscious effort. Once things shift toward passive behavior analysis, Facebook’s News Feed begins to understand what you care about more than you ever could.
With that said, I wouldn’t expect any dramatic changes to what pops up in your feed — at least, not immediately. It’ll take some time/polish before they can give this data too much weight. They’ll have to account for things like users walking away from their computers with the news feed up but sitting on some random nonsense, and, on the other end, the folks (like me) who just mindlessly flick through the feed when bored without actually looking at much of anything..
Facebook says it’ll be rolling out the algorithm tweak in the coming weeks — but before all you social media managers of the world start panicking and coming up with new strategies involving super-long GIFs to keep people hovering, they also say that they “do not expect Pages to see significant changes in distribution as a result of this update”.
Transforming a graphical user interface screenshot created by
a designer into computer code is a typical task conducted by a developer in
order to build customized software, websites and mobile applications. In this
paper, we show that Deep Learning techniques can be leveraged to automatically
generate code given a graphical user interface screenshot as input. Our model
is able to generate code targeting three different platforms (i.e. iOS, Android
and web-based technologies) from a single input image with over 77% of accuracy.
In mathematics, inclusive OR is given preference to exclusive OR (also called XOR).
For example, when you write p V q which is read "p OR q", this is inclusive OR. This statement is true when p is true, or q is true, or both p and q is true. Inclusive OR is used as the default meaning of OR, and works more often in logic than exclusive OR.
We often see XOR used in sentences. For example, if someone says "This summer, I am going to London, or I am going to Paris", they seem to suggest that they plan to go to one or the other, but not both. Even though their statement wouldn't be considered wrong if they went to both cities, it suggests very strongly that they intend to go to one city. (Of course, in logic, it's hard to convey the notion "suggests very strongly").
You would think XOR wouldn't be that interesting an operator. It's similar to OR, so why should it be any more interesting than OR?
But it is!
Various Views of XOR
You can think of XOR in many ways. Assume that p and q are Boolean variables. Also assume that p1, p2, ...pn are Boolean variables. Let (+) be the XOR operator (this is a circle with a plus sign inside it). In this case, we assume that p and q are boolean values, instead of words, and we assume (+) is plain XOR, not bitwise XOR. Later on, we'll use it as bitwise XOR.
p (+) q is true if exactly one of p and q is true. This is the conventional definition of XOR.
p1 (+) p2 (+) ... (+) pn is true if the number of variables with the value true is odd (and is false if the number of variables with the value true is even). Notice this definition ignores the variables which are assigned to false.This may seem like an odd view of XOR. (No pun intended). However, if you believe that XOR is associative (which it is), it's merely an extension of the first definition of XOR.
This definition makes sense, if you read the next definition.
p1 (+) p2 (+) ... (+) pn is the same as adding modulo 2. If pi is true, then treat it as a 1, otherwise treat it as a 0. Then, XOR operation is equivalent to:
Thus, XOR applied to a bunch of Boolean variables is the same as summing up all the variables' values (where true is 1 and false is 0), and dividing mod 2. Recall that dividing mod 2 is one way to determine if a number is even or odd. Since only the variables that have value 1 contribute to the sum (0 is the identity value in sums), this determines how many variables have value 1.
Parity Check
People often use XOR as a means of doing a parity check. A bitstring has even parity if the number of 1's in the string is even. It has an odd parity if the number of 1's is odd. If you XOR the bits together, you can tell whether a bitstring has even or odd parity.
This can often be used to verify data sent across a network, where there's some probability a bit may be corrupted. For example, suppose you're sending N bytes across the network from a source location to a destination location.
How can you determine whether the bytes were sent correctly? One way is to use a kind of checksum, which uses XOR. Each byte can be written as b7b6...b0. For each byte, XOR all the bits in position bi.
If N was 10, and you're transmitting 10 bytes, then create an 11th byte where bi is the XOR of all 10 bytes ith bit. This 11th byte is called the checksum. This checksum is also sent across the network.
At the destination end, where the data is being received, you can then independently perform the checksum again, and see if the checksum you performed matches the checksum sent across. If so, then you have some confidence that no bytes were corrupted. If it's not the same, then the network has corrupted some bytes, and you may need to retransmit the data.
Clearly the system could have errors. For example, if two bits were flipped, say, bit 3 of bytes 4 and 5, then the checksum would be the same if they hadn't been flipped, but there would still be errors. Nevertheless, it catches some errors.
Properties of XOR
Here are several useful properties of XOR. This applies to plain XOR and bitwise XOR.
x (+) 0 = xXORing with 0 gives you back the same number. Thus, 0 is the identity for XOR.
x (+) 1 = \xXORing with 1 gives you back the negation of the bit. Again, this comes from the truth table. For bitwise XOR, the property is slightly different: x ^ ~0 = ~x . That is, if you XOR with all 1's, the result will be the bitwise negation of x.
x (+) x = 0XORing x with itself gives you 0. That's because x is either 0 or 1, and 0 (+) 0 = 0 and 1 (+) 1 = 0.
XOR is associative.That is: (x (+) y) (+) z = x (+) (y (+) z).
You can verify this by using truth tables.
XOR is commutative.That is: x (+) y = y (+) x.
You can verify this by using truth tables.
Bitwise XOR
The properties of XOR apply to bitwise XOR. Suppose x and y are 32 bit words. Then, x ^ y is basically like performing 32 XORs in parallel on an array of 32 booleans.
Swapping without "temp"
Here's one of those brain-teasers that you can give to your CS friends. One of the classic problems any CS major should be able to solve is writing code to swap two numbers. Here's how it looks in C.
temp = x ;
x = y ;
y = temp ;
To swap, you introduce a "temp" variable. Its name doesn't have to be "temp", but it is nevertheless an additional temporary variable.
Now ask your friend to solve this without using a temp variable. This means you can ONLY use x and y. This does NOT mean that you name the variable temp2.
How can you do this? If you're thinking "perhaps I can use bitwise XOR", you're right! If you're adventuresome, you can think about how to do this on your own, but if not, here's the answer.
x = x ^ y ;
y = x ^ y ;
x = x ^ y ;
Are you convinced this works? Perhaps not. How could you be convinced this works?
The key to convincing yourself this works is to keep track of the original value of x and y. Let A be the original value of x (that is, the value x has just before running these three lines of code). Similarly, let Bbe the original value of y.
We can comment each line of code to see what's happening.
// x == A, y == B
x = x ^ y ;
// x == A ^ B, y == B
y = x ^ y ;
// x == A ^ B // y == (A ^ B) ^ B == A ^ (B ^ B) (by Assoc) // == A ^ 0 (by z ^ z == 0 property) // == A (by z ^ 0 == z property)
x = x ^ y ;
// x == ( A ^ B ) ^ A // == ( A ^ A ) ^ B (by Assoc/Commutativity) // == 0 ^ B (by z ^ z == 0 property) // == B (by z ^ 0 == z property) // y == A
After the second statement has executed, y = A. After the third statement, x = B.
Now it turns out you can do a similar trick using subtraction instead of XOR. Doing swaps with XOR is slightly safer than swapping with subtraction because subtraction can cause overflow. However, usually overflow occurs in a "nice way" that it may still work. Overflow often just "wraps around", so things may still work out fine.
Writing bitwise XOR without ^
Suppose you wanted to implement bitwise XOR, but didn't have ^ operator. What would you do? With bitwise AND (&) and bitwise OR (|), you can do this.
x ^ y == (~x & y) | (x & ~y)
This is the standard definition of XOR as defined in logic books, applied to bitwise operations.
Summary
XOR is an interesting operation. With it, you can do parity checks and swaps without temp variables. source: https://www.cs.umd.edu/
This repository contains a library that allows native Linux programs to load and call functions from a Windows DLL.
How does it work?
The peloader directory contains a custom PE/COFF loader derived from ndiswrapper. The library will process the relocations and imports, then provide a dlopen-like API. The code supports debugging with gdb (including symbols), basic block coverage collection, and runtime hooking and patching.
What works?
The intention is to allow scalable and efficient fuzzing of self-contained Windows libraries on Linux. Good candidates might be video codecs, decompression libraries, virus scanners, image decoders, and so on.
C++ exception dispatch and unwinding.
Loading additional symbols from IDA.
Debugging with gdb (including symbols), breakpoints, stack traces, etc.
Runtime hooking and patching.
Support for ASAN and Valgrind to detect subtle memory corruption bugs.
If you need to add support for any external imports, writing stubs is usually quick and easy.
Why?
Distributed, scalable fuzzing on Windows can be challenging and inefficient. This is especially true for endpoint security products, which use complex interconnected components that span across kernel and user space. This often requires spinning up an entire virtualized Windows environment to fuzz them or collect coverage data.
This is less of a problem on Linux, and I've found that porting components of Windows Antivirus products to Linux is often possible. This allows me to run the code I’m testing in minimal containers with very little overhead, and easily scale up testing.
This is just personal opinion, but I also think Linux has better tools. ¯\_(ツ)_/¯
Windows Defender
MsMpEng is the Malware Protection service that is enabled by default on Windows 8, 8.1, 10, Windows Server 2016, and so on. Additionally, Microsoft Security Essentials, System Centre Endpoint Protection and various other Microsoft security products share the same core engine.
The core component of MsMpEng responsible for scanning and analysis is called mpengine. Mpengine is a vast and complex attack surface, comprising of handlers for dozens of esoteric archive formats, executable packers, full system emulators for various architectures and interpreters for various languages. All of this code is accessible to remote attackers.
Dependencies
Fedora / RedHat
Ubuntu / Debian
Comment
glibc-devel.i686
libc6-dev:i386
libgcc.i686
gcc-multilib
readline-devel.i686
libreadline-dev:i386
Optional, used in mpscript.
cabextract
cabextract
Used to extract definitions.
If you want to know which version you got, try this:
$ exiftool mpengine.dll | grep 'Product Version Number'
Product Version Number : 1.1.13701.0
Debugging
If you want to debug a crash, single step through a routine or set breakpoints, follow these examples. First, you need a map file from IDA.
Microsoft doesn't release public symbols for every build, and sometimes the symbols lag behind for a few months after release. Make sure you're using an mpengine version with public symbols available.
Use the following sample commandline to generate map and idb files.
> idaw -A -P+ -S"createmap.idc mpengine.map" mpengine.dll
If you generate the map files on Windows, you'll get CRLF line terminators, fix them like this:
$ dos2unix mpengine.map
When you run mpclient under gdb, it will detect a debugger and print the commands you need to enter to teach gdb about the symbols:
$ gdb -q ./mpclient
(gdb) r testfile.txt
Starting program: mpclient
main(): GDB: add-symbol-file engine/mpengine.dll 0xf6af4008+0x1000
main(): GDB: shell bash genmapsym.sh 0xf6af4008+0x1000 symbols_19009.o < mpengine.map
main(): GDB: add-symbol-file symbols_19009.o 0
Program received signal SIGTRAP, Trace/breakpoint trap.
0x0804d213 in main (argc=1, argv=0xffffcc64, envp=0xffffcc6c) at mpclient.c:156
156 __debugbreak();
(gdb)
If you enter the commands it shows into gdb, you will have symbols available.
(gdb) add-symbol-file engine/mpengine.dll 0xf6af4008+0x1000
add symbol table from file "engine/mpengine.dll" at
.text_addr = 0xf6af5008
Reading symbols from engine/mpengine.dll...done.
(gdb) shell bash genmapsym.sh 0xf6af4008+0x1000 symbols_19009.o < mpengine.map
(gdb) add-symbol-file symbols_19009.o 0
add symbol table from file "symbols_19009.o" at
.text_addr = 0x0
Reading symbols from symbols_19009.o...done.
(gdb) p as3_parsemetadata_swf_vars_t
$1 = {void (void)} 0xf6feb842 <as3_parsemetadata_swf_vars_t>
Then you can continue, and it will run as normal.
(gdb) c
Breakpoints, watchpoints and backtraces all work as normal, although it may be more reliable to use hardware breakpoints than software breakpoints.
To use hardware breakpoints in gdb, you just use hb or hbreak instead of break. Note that you only get a limited number of hardware breakpoints.
(gdb) b as3_parsemethodinfo_swf_vars_t
Breakpoint 1 at 0xf6feb8da
(gdb) c
Continuing.
main(): Scanning test/input.swf...
EngineScanCallback(): Scanning input
Breakpoint 1, 0xf6feb8da in as3_parsemethodinfo_swf_vars_t ()
(gdb) bt
#0 0xf6feb8da in as3_parsemethodinfo_swf_vars_t ()
#1 0xf6dbad7f in SwfScanFunc ()
#2 0xf6d73ec3 in UfsScannerWrapper__ScanFile_scanresult_t ()
#3 0xf6d6c9e3 in UfsClientRequest__fscan_SCAN_REPLY ()
#4 0xf6d6a818 in UfsNode__ScanLoopHelper_wchar_t ()
#5 0xf6d6a626 in UfsNode__Analyze_UfsAnalyzeSetup ()
#6 0xf6d71f7f in UfsClientRequest__AnalyzeLeaf_wchar_t ()
#7 0xf6d71bb9 in UfsClientRequest__AnalyzePath_wchar_t ()
#8 0xf6dbbd88 in std___String_alloc_std___String_base_types_char_std__allocator_char______Myptr_void_ ()
#9 0xf6d75e72 in UfsCmdBase__ExecuteCmd__lambda_c80a88e180c1f4524a759d69aa15f87e____lambda_c80a88e180c1f4524a759d69aa15f87e__ ()
Backtrace stopped: previous frame inner to this frame (corrupt stack?)
(gdb) x/3i $pc
=> 0xf6feb8da <as3_parsemethodinfo_swf_vars_t+7>: lea ebx,[edx+0x1c]
0xf6feb8dd <as3_parsemethodinfo_swf_vars_t+10>: push esi
0xf6feb8de <as3_parsemethodinfo_swf_vars_t+11>: mov edx,ebx
What about Wine and Winelib?
This project does not replace Wine or Winelib.
Winelib is used to port Windows C++ projects to Linux, and Wine is intended to run full Windows applications. This project is intended to allow native Linux code to load simple Windows DLLs.
The closest analogy would be ndiswrapper but for userspace.
