Bouncy Castle C#

by Jesse 29. July 2009 11:54

It has been really long time since my last post. And finally I get a few minutes to write this post on using BouncyCacle encryption in C#, hopefully it can help some one.

BouncyCastle is a encryption library widely used in Java, and has been porting to C# ages ago. But due to lack of documentation, I believe many people including myself have much trouble on implement any encrypt/decrypt functions by using it. Right, let's start.

 

First of all, you need to get BouncyCastle library from its website on http://www.bouncycastle.org/csharp/. It is not necessary to get the source code. Also, there are two type of binary format libraries you can download. One is with IDEA, and another is not. If you dont know which one you need, just download the one without IDEA. As IDEA is patented in many country, so you must be more careful when choosing to use.

My implementation consist of two  parts: block cipher encryption engine, and encryption/decryption interface.

BCEngine class (Block cipher engine)

public class BCEngine
    {
        private readonly Encoding _encoding;
        private readonly IBlockCipher _blockCipher;
        private PaddedBufferedBlockCipher _cipher;
        private IBlockCipherPadding _padding;

        public BCEngine(IBlockCipher blockCipher, Encoding encoding)
        {
            _blockCipher = blockCipher;
            _encoding = encoding;
        }

        public void SetPadding(IBlockCipherPadding padding)
        {
            if(padding != null)
                _padding = padding;
        }

        public string Encrypt(string plain, string key)
        {
            byte[] result = BouncyCastleCrypto(true, _encoding.GetBytes(plain), key);
            return Convert.ToBase64String(result);
        }

        public string Decrypt(string cipher, string key)
        {
            byte[] result = BouncyCastleCrypto(false, Convert.FromBase64String(cipher), key);
            return _encoding.GetString(result);
        }

        /// <summary>
        ///
        /// </summary>
        /// <param name="forEncrypt"></param>
        /// <param name="input"></param>
        /// <param name="key"></param>
        /// <returns></returns>
        /// <exception cref="CryptoException"></exception>


        private byte[] BouncyCastleCrypto(bool forEncrypt, byte[] input, string key)
        {
            try
            {
                _cipher = _padding == null ? new PaddedBufferedBlockCipher(_blockCipher) : new PaddedBufferedBlockCipher(_blockCipher, _padding);
                byte[] keyByte = _encoding.GetBytes(key);
                _cipher.Init(forEncrypt, new KeyParameter(keyByte));
                return _cipher.DoFinal(input);
            }
            catch (Org.BouncyCastle.Crypto.CryptoException ex)
            {
                throw new CryptoException(ex);
            }
        }
    }

 

The encryption/decryption interface:

public string AESEncryption(string plain, string key, bool fips)
        {
            BCEngine bcEngine = new BCEngine(new AesEngine(), _encoding);
            bcEngine.SetPadding(_padding);
            return bcEngine.Encrypt(plain, key);
        }

        public string AESDecryption(string cipher, string key, bool fips)
        {
            BCEngine bcEngine = new BCEngine(new AesEngine(), _encoding);
            bcEngine.SetPadding(_padding);
            return bcEngine.Decrypt(cipher, key);
        }

 

You can easily change the BouncyCastle engine to Blowfish, DES, TripleDES, TwoFish, etc.

TinyMCE IE 8 usability issue

by Jesse 12. June 2009 09:06

I am a big TinyMCE fan, and moved from FCKEditor years ago due to its light-weight, fast and compability with different browsers. But recently found a usability issue when using its browsing server functions, the popup browsing window is behand TinyMCE windows. I though it was something wrong with my custom image browser, but it is actually happening on its demo site.

http://tinymce.moxiecode.com/examples_im/example_01.php

I am hoping TinyMCE developers can fix it asap.

 

Bug is reported on https://sourceforge.net/tracker/?func=detail&aid=2805302&group_id=103281&atid=635682

 

update:

It looks like developing team not interesting the bug reported. I found a work around by enabling inlinepopup plugin. Basic it makes the TinyMCE popup windows always on the top of parent windown, same to showmodal method.

Tags: , , , ,
Categories: Coding | ASP .NET

Make "Repository Factory" work on VS 2008

by Jesse 5. June 2009 13:33

I am writing another post at the same time to compare several MS ORM technic. Put the result first, I finally decide to use "Repository Factory". Well, it is NOT really a ORM, but a code generator like "MyGeneration". The reason I like it is: 1. it is open-source. it is very important if you want to use a long-last technic, and not need to worry about MS abandoning it during your projects are still going. 2. it is light-weight. comparing ADO.NET EF, it doesnt eat into your performance lots. There are so many reason I want to use it, even Patterns & Practice team gave up this project.

I download the source code from https://RepositoryFactory.svn.codeplex.com/svn, the last commition is Feb this year! The good news, or say best news, is the solution is compilable. But the bad news is it is not working!!!! I can tell the code in SVN trunk is a incomplete/bugy copy of RF. You have to change couple things to make it. The issues mentioned in below posts on Codeplex are still there, I put my patch in or find a workaround.

http://repositoryfactory.codeplex.com/Thread/View.aspx?ThreadId=32194
http://repositoryfactory.codeplex.com/Thread/View.aspx?ThreadId=46567

The main changes are done in "t4" files (template file, Im interesting to know where the name t4 comes from if anyone knows). Download them as you will, and use it as your risk. If you know other fixs, please do leave comments. It will benifit all of us.

Repository Factory VS 2008 Fix.rar (8.13 kb)

Fix W3C validation failure on ImageButton control (Server-wise)

by Jesse 18. May 2009 19:55

Recently runs into a problem on passing validation my .NET pages on W3C validator(http://validator.w3.org). Generally speaking the HTML code rendered from ImageButton control contains a invalid html tag border="0" which caused failure on passing XHTML 1.0 Transitional check.

Microsoft claimed it is not their issue, as it is not appear in "View code" of IE, which sounds more like an excuse to me. Dig several pages in google, one guy in asp.net forume suggested to use app_browser file which is working for me. Following is my w3c.browser file which sits in ~/App_Browsers folder


<browsers>
    <browser id="W3C" parentID="default">
        <identification>
            <userAgent match="^W3C_Validator" />
        </identification>

        <capture>
            <userAgent match="^W3C_Validator/(?'version'(?'major'\d+)(?'minor'\.\d+)\w*).*" />
        </capture>

        <capabilities>
          <capability name="browser" value="w3cValidator" />
          <capability name="majorversion" value="${major}" />
          <capability name="minorversion" value="${minor}" />
          <capability name="version" value="${version}" />
          <capability name="w3cdomversion" value="1.0" />
          <capability name="xml" value="true" />
          <capability name="tagWriter" value="System.Web.UI.HtmlTextWriter" />
        </capabilities>
    </browser>
</browsers>

However, there are many websites running on my server, it is not a enjoyable jobs to copy it to every website. A server-wise solution will be a big time-saver. Read the post about "Browser Definition File Schema" (http://msdn.microsoft.com/en-us/library/ms228122.aspx) carefully, I mean line by line and word by word. You may find following paragraph

However, if changes are made to .browser files in the %SystemRoot%\Microsoft.NET\Framework\version\CONFIG\Browsers directory, you must manually recompile the application by using the %SystemRoot%\Microsoft.NET\Framework\version\aspnet_regbrowsers.exe tool

Haha, this sounds like a server-wise solution. I copied my w3c.browser to both C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\CONFIG\Browsers and C:\WINDOWS\Microsoft.NET\Framework64\v2.0.50727\CONFIG\Browsers, if you cannot find the second folder, you may be running on a 32 bit system, so don't need to worry about it. And the last thing needs to do

C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\aspnet_regbrowsers.exe -i

The assembly will automatically installed into GAC. ^_^

Just out of curiosity, I reflected the code aspnet_regbrowsers generated. If you are a "dead cat" like me, here is the code

private bool W3cProcess(NameValueCollection headers, HttpBrowserCapabilities browserCaps)
{
    IDictionary capabilities = browserCaps.Capabilities;
    string target = browserCaps[string.Empty];
    RegexWorker worker = new RegexWorker(browserCaps);
    if (!worker.ProcessRegex(target, "^W3C_Validator"))
    {
        return false;
    }
    worker.ProcessRegex(browserCaps[string.Empty], @"^W3C_Validator/(?'version'(?'major'\d+)(?'minor'\.\d+)\w*).*");
    capabilities["browser"] = "w3cValidator";
    capabilities["majorversion"] = worker["${major}"];
    capabilities["minorversion"] = worker["${minor}"];
    capabilities["version"] = worker["${version}"];
    capabilities["w3cdomversion"] = "1.0";
    capabilities["xml"] = "true";
    capabilities["tagWriter"] = "System.Web.UI.HtmlTextWriter";
    browserCaps.AddBrowser("W3C");
    this.W3cProcessGateways(headers, browserCaps);
    bool ignoreApplicationBrowsers = false;
    this.W3cProcessBrowsers(ignoreApplicationBrowsers, headers, browserCaps);
    return true;
}

protected virtual void W3cProcessBrowsers(bool ignoreApplicationBrowsers, NameValueCollection headers, HttpBrowserCapabilities browserCaps)
{
}

protected virtual void W3cProcessGateways(NameValueCollection headers, HttpBrowserCapabilities browserCaps)
{
}

Good post about BlogEngine.NET

by Jesse 8. May 2009 11:14

BlogEngine .NET is getting interested me. Believe or not, it uses quite a lot advanced coding technic, such as MVC, provider-based model, open search, extensible api, etc.

If you are interested to know more, and you can read chinese, try the following page. or using google translate tool, you won't regret the time spending on it

http://www.cnblogs.com/Thriving-Country/archive/2008/11/14/1333739.html

Tags: , , ,
Categories: .NET | Coding | ASP .NET

Powered by BlogEngine.NET 1.5.0.7
Theme by Mads Kristensen | Modified by Mooglegiant