Finally I found an implementation of scrypt in C# in the [CryptSharp library][2].&lt;br&gt;
The library is open source and uses the [ISC license][1].

 - [**CryptSharp**][2]

&gt; **Version History**
&gt;
&gt; 1.2.0 January 23, 2011:&lt;br&gt;
&gt; The SCrypt KDF is now supported as CryptSharp.Utility.SCrypt.&lt;br&gt;
&gt; Added djb&#39;s Salsa20, required by SCrypt.


  [1]: http://en.wikipedia.org/wiki/ISC_license
  [2]: http://www.zer7.com/software.php?page=cryptsharp

In case, like me, you came to this question via a quick google (came up as the top link) you can now download SCrypt as a Nuget package into your project.

    PM&gt; Install-Package Scrypt.NET

Use as follows:

    ScryptEncoder encoder = new ScryptEncoder();
    string hashsedPassword = encoder.Encode(&quot;mypassword&quot;);

and comparing

    ScryptEncoder encoder = new ScryptEncoder();
    bool areEquals = encoder.Compare(&quot;mypassword&quot;, hashedPassword);

[Github link here][1]


  [1]: https://github.com/viniciuschiele/scrypt

There&#39;s a new implementation of SCrypt for .NET here: https://github.com/replicon/Replicon.Cryptography.SCrypt

Unlike CryptoSharp, which is a great library, this one is implemented as a packaged wrapper around a native library.  This allows it to use native-level instructions (like SSE2) to improve the performance of the implementation quite a bit.

The downside is that it has to contain native compiled assemblies, detect the right one to use, unpackage it, and then load it.  That means it&#39;s not ideal for all environments, but it works great where it works.

I am studying for an undergraduate databases course.

I&#39;d like to know if there are any online sites that allow me to do queries against an already built and populated database (with a known schema), so I didn&#39;t have to install SQL and populate it with data myself.

I am currently doing some exercises by hand on a workbook I have here, but I&#39;m a bit afraid that I might be doing them wrong and it&#39;s hard to check their correctness without testing them against the &quot;real thing&quot;.

Thanks

(In our course we are using Oracle)

Online databases for trying out Oracle SQL queries?

I have a Rails 3 application and I want to print in the view the request parameters. How do I do it?


Edit:

The purpose is to see what is being sent in a Form.

Rails: How do I print the request parameters?

I&#39;ve read about [scrypt][1] and some of its advantages over the [bcrypt][2] hashing algorithm in certain circumstances. 

Anyhow, it seems scrypt isn&#39;t as widely used yet. Has anyone seen so far a .NET implementation of it (favored in C#)?

  [1]: http://www.tarsnap.com/scrypt.html
  [2]: http://en.wikipedia.org/wiki/Bcrypt

.NET implementation of scrypt

<p>I've read about <a href="http://www.tarsnap.com/scrypt.html" target="_blank" rel="noopener noreferrer">scrypt</a> and some of its advantages over the <a href="http://en.wikipedia.org/wiki/Bcrypt" target="_blank" rel="noopener noreferrer">bcrypt</a> hashing algorithm in certain circumstances.</p>
<p>Anyhow, it seems scrypt isn't as widely used yet. Has anyone seen so far a .NET implementation of it (favored in C#)?</p>


i am trying to find total pages in building a pager on a website (so i want the result to be an integer.  i get a list of records and i want to split into 10 per page (the page count)

when i do this:

    list.Count() / 10

 or

    list.Count() / (decimal)10

and the `list.Count() =12`, i get a result of `1`. 

How would I code it so i get `2` in this case (the remainder should always add `1`) 

how to always round up to the next integer

VS2010: 

In VB I can place the cursor inside an existing method&#39;s parameter brackets and type a &#39;space&#39;, which will bring up the tooltip with description of the parameter I&#39;m at. This is not the case in C#. I have to delete the whole brackets including the parameters, and retype the left bracket, for this tooltip to show. Is there some shortcut or setting to change this behavior? I tried hitting ctrl, shift, alt, but it has no effect. 

How to show method parameter tooltip in C#?

When I fill a DataGridView with data, there is always an empty row at the bottom.
How do I disable this?

How do I remove the empty row from the bottom of a DataGridView control?

I was of the impression that in C#, struct elements are allocated on the stack and thus disappear when returning from a method in which they were created. But what happens if I place the struct-values in a list and return that? The elements survives. **Are struct instances sometimes allocated on the heap?**


    internal struct Stru
    {
      public int i;
    }
  
    internal class StruTry
    {
      public List&lt;Stru&gt; Get(int max)
      {
        var l = new List&lt;Stru&gt;();
        for (int i = 0; i &lt; max; i++)
          l.Add(new Stru {i=i});

        return l;
      }
    }


code printing 0, 1, 2

    [Test]
    public void T()
    {
      var ll = new StruTry().Get(3);
      foreach (var stru in ll)
        Console.WriteLine(&quot;* &quot;+ stru.i);
    }



Are Structs always stack allocated or sometimes heap allocated?

I have a byte, specifically one byte from a byte array which came in via UDP sent from another device. This byte stores the on/off state of 8 relays in the device.

How do I get the value of a specific bit in said byte? Ideally an extension method would look the most elegant and returning a bool would make the most sense to me.

    public static bool GetBit(this byte b, int bitNumber)
    {
        //black magic goes here
    }



Get a specific bit from byte

If I have code like this

    if(true){

and I add

    }

it is transformed into

    if (true)
    {
    }

but I would like it to stay in format

    if (true) {
    }

Even if I copy code that has `if` like this, it is transformed into the longer version.

P.S. I understand that it&#39;s a C++ and C# standard to use the longer version, however I do come from a different standard, and it&#39;s easier for me to use the shorter version.

**I bet there is some formatter option that can be turned off or changed.**

How to make Visual Studio not put { on a new line?

I am writing a prototype TCP connection and I am having some trouble homogenizing the data to be sent.

  At the moment, I am sending nothing but strings, but in the future we want to be able to send any object. 

 The code is quite simple at the moment, because I thought everything could be cast into a byte array:

    void SendData(object headerObject, object bodyObject)
    {
      byte[] header = (byte[])headerObject;  //strings at runtime, 
      byte[] body = (byte[])bodyObject;      //invalid cast exception

      // Unable to cast object of type &#39;System.String&#39; to type &#39;System.Byte[]&#39;.
      ...
    }

This of course is easily enough solved with a 

    if( state.headerObject is System.String ){...}

The problem is, if I do it that way, I need to check for EVERY type of object that can&#39;t be cast to a byte[] at runtime.

  Since I do not know every object that can&#39;t be cast into a byte[] at runtime, this really isn&#39;t an option.

How does one convert any object at all into a byte array in C# .NET 4.0?

Convert any object to a byte[]

&gt; **Possible Duplicate:**  
&gt; [ReSharper and var](https://stackoverflow.com/questions/737835/resharper-and-var)  

&lt;!-- End of automatically inserted text --&gt;

After I have installed ReSharper it demands(by warnings) that I use var whenever possible, for example

    UnhandledExceptionEventArgs ue = (UnhandledExceptionEventArgs) t;

ReSharper wants to turn it into

    var ue = (UnhandledExceptionEventArgs) t;

I like the first version better, is there any reason to prefer **var**? better performance? anything? or is it just a code style?

Why should I use var instead of a type?

may be it is a simple question but I&#39;m try all of conversion method! and it still has error!
would you help me?

decimal? (nullable decimal) to decimal

How can I convert decimal? to decimal

I have a simple android client which needs to &#39;talk&#39; to a simple C# HTTP listener. I want to provide a basic level of authentication by passing username/password in POST requests.

MD5 hashing is trivial in C# and provides enough security for my needs but I can&#39;t seem to find how to do this at the android end.

EDIT: Just to address the concerns raised about MD5 weakness - the C# server runs on the PCs of the users of my android client. In many cases, they&#39;ll be accessing the server using wi-fi on their own LANs but, at their own risk, they may choose to access it from the internet. Also the service on the server needs to use pass-through for the MD5 to a 3rd party application I have no control over.

MD5 hashing in Android

I see a lot of confusion between hashes and encryption algorithms and I would like to hear some more expert advice about:

1. When to use hashes vs encryptions

2. What makes a hash or encryption algorithm different (from a theoretical/mathematical level)
   i.e. what makes hashes irreversible (without aid of a rainbow tree) 

Here are some *similar* SO Questions that didn&#39;t go into as much detail as I was looking for:

https://stackoverflow.com/questions/184328/what-is-the-difference-between-obfuscation-hashing-and-encryption  
https://stackoverflow.com/questions/3080976/difference-between-encryption-and-hashing

Fundamental difference between Hashing and Encryption algorithms

I need to parse .PEM files.  
I know that the standard for &quot;Privacy-enhanced Electronic Mail&quot; is defined in RFCs 1421-24. But they don&#39;t seem to mention some text I find inside OpenSSL .pem files (eg. &quot;Key Attributes&quot;, &quot;BEGIN CERTIFICATE&quot;, etc...) 
Is this an OpenSSL-specific format?




Where is the PEM file format specified?

How can I hash some string with `sha256` in Java?

How to hash some string with sha256 in Java?

How good are algorithms used in Javascript `Math.random()` in different browsers? Is it okay to use it for generating salts and one-time passwords?

How many bits from one `random` I can use?

Is Math.random() cryptographically secure?

Let&#39;s say I have a dictionary in which the keys map to integers like:

    d = {&#39;key1&#39;: 1,&#39;key2&#39;: 14,&#39;key3&#39;: 47}

Is there a syntactically minimalistic way to return the sum of the values in `d`—i.e. `62` in this case?


How to sum all the values in a dictionary?

I am trying to compare two Ruby Hashes using the following code:

    #!/usr/bin/env ruby
    
    require &quot;yaml&quot;
    require &quot;active_support&quot;
    
    file1 = YAML::load(File.open(&#39;./en_20110207.yml&#39;))
    file2 = YAML::load(File.open(&#39;./locales/en.yml&#39;))
    
    arr = []
    
    file1.select { |k,v|
      file2.select { |k2, v2|
        arr &lt;&lt; &quot;#{v2}&quot; if &quot;#{v}&quot; != &quot;#{v2}&quot;
      }
    }
    
    puts arr

The output to the screen is the full file from file2. I know for a fact that the files are different, but the script doesn&#39;t seem to pick it up.


How do I compare two hashes?

The `boost::hash_combine` template function takes a reference to a hash (called `seed`) and an object `v`. According to the [docs][1], it combines `seed` with the hash of `v` by

&lt;!-- language: cpp --&gt;
    seed ^= hash_value(v) + 0x9e3779b9 + (seed &lt;&lt; 6) + (seed &gt;&gt; 2);

I can see that this is deterministic. I see why a XOR is used.

I bet the addition helps in mapping similar values widely apart so probing hash tables won&#39;t break down, but can someone explain what the magic constant is?


  [1]: http://www.boost.org/doc/libs/release/doc/html/hash/reference.html#boost.hash_combine

Magic number in boost::hash_combine

I&#39;m looking at some code that I have not written myself. The code tries to hash a password with SHA512 and uses just `time()` as the salt. Is `time()` too simple a salt for this or is this code safe?

Thanks for the answers and comments. I will sum it up here for the new readers:

- salt should be different for each user, so if 2 users register at the same time, their salts won&#39;t be unique. This is a problem, but not a big one. 
- but salt shouldn&#39;t be in any way related to the user, so time() is not a good salt. 
- &quot;*Use a random, evenly distributed, high entropy salt.*&quot; -- That&#39;s a mouthful, so what code could possibly generate a `random, evenly distributed, high entropy` salt?

Ok, so how about I replace time() with a random string 32 char long. The random string could be generated from looping 32 times over a set of alphabet chars. Does that sound good?

Is time() a good salt?

I&#39;m using a [Java scrypt library](https://github.com/wg/scrypt) for password storage. It calls for an `N`, `r` and `p` value when I encrypt things, which its documentation refers to as &quot;CPU cost&quot;, &quot;memory cost&quot; and &quot;parallelization cost&quot; parameters. Only problem is, I don&#39;t actually know what they specifically mean, or what good values would be for them; perhaps they correspond somehow to the -t, -m and -M switches on [Colin Percival&#39;s original app](http://www.tarsnap.com/scrypt.html)?

Does anyone have any suggestions for this? The library itself lists N = 16384, r = 8 and p = 1, but I don&#39;t know if this is strong or weak or what.

Content Type	Original Author	Original Content on Stackoverflow
Question	Martin Buberl	View Question on Stackoverflow
Solution 1 - C#	Martin Buberl	View Answer on Stackoverflow
Solution 2 - C#	VictorySaber	View Answer on Stackoverflow
Solution 3 - C#	mfenniak	View Answer on Stackoverflow

.NET implementation of scrypt

C# Problem Overview

C# Solutions

Solution 1 - C#

Solution 2 - C#

Solution 3 - C#

Rails: How do I print the request parameters?

Online databases for trying out Oracle SQL queries?

Attributions