Question

Hash a string VB.net

Asked by: CraigLazar

Hi,
Is there a simple method using perhaps a key to hash and unhash a string value using the ,net framework ONLY?
my app is running on Framework 2 and up

I would like to Hash example "Hello World", then be able to pass the "Hashed" value into a function to dehash it back to "Hello World"

thanks allot

This Question has been solved and asker verified All Experts Exchange premium technology solutions are available to subscription members.

Subscribe now for full access to Experts Exchange and get

Instant Access to this Solution

  • Plus...
  • 30 Day FREE access, no risk, no obligation
  • Collaborate with the world's top tech experts
  • Unlimited access to our exclusive solution database
  • Never be left without tech help again

Subscribe Now

Asked On
2009-10-12 at 07:09:14ID24804552
Topics

.NET

,

Visual Studio

,

Microsoft Visual Basic.Net

Participating Experts
4
Points
500
Comments
8

Trusted by hundreds of thousands everyday for fast, accurate and reliable tech support.

  • "The time we save is the biggest benefit of Experts Exchange to Warner Bros. What could take multiple guys 2 hours or more each to find is accessed in around 15 minutes on Experts Exchange." Mike Kapnisakis, Warner Bros.
  • "Our team likes having a resource that is more secure than just using Google and most experts using this service really know their stuff. It's nice to look here first versus using Google." Dayna Sellner, Lockheed Martin
  • "Anytime that I've been stumped with a problem, 9 out of 10 times Experts Exchange has either the accepted solution or an open discussion of the potential solution to the problem." Kenny Red, eBay Inc.

See what Experts Exchange can do for you.

Got a question?

We've got the answer.

Experts Exchange has been collecting answers to technology questions since 1996…3 million and counting! If you have a question, chances are we already have your answer.

Screenshot of Experts Exchange Knowledgebase

Need individual assistance?

Our experts are ready to help.

If you can't find the exact answer you're looking for, ask our exclusive community of 50,000 experts. You’ll get a personalized answer from a trusted professional.

Screenshot of Experts Exchange Knowledgebase

Want to learn from the best?

Read articles from industry experts.

Thousands of free tech tips, tricks, how-to’s and tutorials are available in our peer reviewed articles section. See for yourself how smart our experts are, no login required.

Screenshot of an Article

Working on a long term project?

Store your work and research.

Save solutions to your questions, answers you’ve discovered through searching plus helpful articles in your personal knowledgebase for easy future access.

Screenshot of Experts Exchange Knowledgebase

Access the answers to your technology questions today.

Subscribe Now

30-day free trial. Register in 60 seconds.

What Makes Experts Exchange Unique?

Members of the expert community talk about why the experience at Experts Exchange is different than what you will find anywhere else.

Trusted by the world's most respected brands.

image of each brand's logo

Faithfully serving IT professionals since 1996.

Experts Exchange Logo

Try it out and discover for yourself.

Subscribe Now

30-day free trial. Register in 60 seconds.

Related Solutions

  1. hashing
    How will i make a Hash table? Including its source code?
  2. Hashing
    Hi experts, I have files that consists of a list of passwords, the passwords are to have at least 3 of the following kinds: lower case alpha, upper case alpha, numbers and punctuations. They have length 8 to 14. The problem is that they are in random order. And I do not want...
  3. Comparing MD5 Hashed strings
    Hi, I have some trouble comparing hashed strings between .Net and .Net Compact Framework. I used normal VB.NET to store a MD5 hashed string in a database. I used the following code to create and compare the same hash (at least, that is what i thought) using VB.NET Compact Fr...

Free Tech Articles

  1. WARNING: 5 Reasons why you should NEVER fix a computer for free.
    It is in our nature to love the puzzle. We are obsessed. The lot of us. We love puzzles. We love the challenge. We thrive on finding the answer. We hate disarray. It bothers us deep in our soul. W...
  2. SCCM OSD Basic troubleshooting
    SCCM 2007 OSD is a fantastic way to deploy operating systems, however, like most things SCCM issues can sometimes be difficult to resolve due to the sheer volume of logs to sift through and the dispe...
  3. Migrate Small Business Server 2003 to Exchange 2010 and Windows 2008 R2
    This guide is intended to provide step by step instructions on how to migrate from Small Business Server 2003 to Windows 2008 R2 with Exchange 2010. For this migration to work you will need the fo...
  4. Create a Win7 Gadget
    This article shows you how to create a simple "Gadget" -- a sort of mini-application supported by Windows 7 and Vista. Gadgets can be dropped anywhere on the desktop to provide instant information, ...
  5. Outlook continually prompting for username and password
    There have been a lot of questions recently regarding Outlook prompting for a username and password whilst using Exchange 2007. There are a few reasons why this would happen and I will try to cover t...
  6. Backup Exchange 2010 Information Store using Windows Backup
    There seems to be quite a lot of confusion around the ability to backup Exchange 2010 using the built in Windows Backup feature. This stems from the omission of this feature prior to Exchange 2007 s...

Cloud Class Webinars

  1. Avoiding Bugs in Microsoft Access
    Alison Balter takes and in-depth look at avoiding bugs in Access. In this webinar you will learn about using the immediate window to debug your applications, invoking the debugger, using breakpoints to troubleshoot, stepping through code, setting the next statement to execute, ...
  2. Top 10 Best New Features in Visio 2010
    Scott Helmers gives live demonstrations of the top 10 new features in Visio 2010. This webinar will teach you how to create compelling diagrams by adding shapes to the page with a single click, linking the shapes in a diagram to data in Excel (or SQL Server, or SharePoint), ...
  3. IT Consultant Business Secrets Revealed
    Michael Munger, Experts Exchange tech pro and IT consultant, pulls back the curtain on his very successful businesses and answers question on every IT consultant and business owner should know about. He shares secrets on what he did to solve the 5 most common problems in IT, ...
  4. Disaster Recovery and Business Continuity
    Quest CTO, Mike Billon, gives an overview of the steps involved in building a dunamic disaster recovery plan. Through case studies and an examination of software/hardware tooles for monitoring and testing, you'll gain a better understandin of where you are, where you want ...
  5. Organize Your Visio Diagrams with Containers and Lists
    Scott Helmers uses cross functional flowcharts, wireframe diagrams, data graphic legends and seating charts to teach you: how to ustilize all three new structured diagram components in Visio 2010, the best practices for organizeing shapes in previous version of Visio, how to organize ...
  6. How to Us Objects, Properties, Events and Methods in Microsoft Access
    Alison Dalter gives an in-depbth look at objects, properties, events and methods in Microsoft Access. In this webinar you will learn about using the object browser, referring to objects, working with properties and methods, working with object variables, understanding the ...

Join the Community

Give a Little. Get a Lot.

Join the community of experts here and help other tech pros by answering question in your area of expertise. You can earn FREE access to all Experts Exchange's premium features and resources.

Join the Community

Answers

 

by: akosterPosted on 2009-10-12 at 07:16:24ID: 25551410

You can use a hash code to verify that that a user inputted string matches "Hello world", but a hash cannot be 'dehashed' into its original form.

For that you will need to use encryption or if security is not an issue use binary serialization

 

by: wrmichaelPosted on 2009-10-12 at 07:18:12ID: 25551421

 

by: CodeCruiserPosted on 2009-10-12 at 07:20:19ID: 25551442

I use this class



Imports System
Imports System.IO
Imports System.Text
Imports System.Security.Cryptography
 
Public Class TripleDES
    Private key() As Byte = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24}
    Private iv() As Byte = {65, 110, 68, 26, 69, 178, 200, 219}
 
    Public Function Encrypt(ByVal plainText As String) As Byte()
        ' Declare a UTF8Encoding object so we may use the GetByte
        ' method to transform the plainText into a Byte array.
        Dim utf8encoder As UTF8Encoding = New UTF8Encoding()
        Dim inputInBytes() As Byte = utf8encoder.GetBytes(plainText)
 
        ' Create a new TripleDES service provider
        Dim tdesProvider As TripleDESCryptoServiceProvider = New TripleDESCryptoServiceProvider()
 
        ' The ICryptTransform interface uses the TripleDES
        ' crypt provider along with encryption key and init vector
        ' information
        Dim cryptoTransform As ICryptoTransform = tdesProvider.CreateEncryptor(Me.key, Me.iv)
 
        ' All cryptographic functions need a stream to output the
        ' encrypted information. Here we declare a memory stream
        ' for this purpose.
        Dim encryptedStream As MemoryStream = New MemoryStream()
        Dim cryptStream As CryptoStream = New CryptoStream(encryptedStream, cryptoTransform, CryptoStreamMode.Write)
 
        ' Write the encrypted information to the stream. Flush the information
        ' when done to ensure everything is out of the buffer.
        cryptStream.Write(inputInBytes, 0, inputInBytes.Length)
        cryptStream.FlushFinalBlock()
        encryptedStream.Position = 0
 
        ' Read the stream back into a Byte array and return it to the calling
        ' method.
        Dim result(encryptedStream.Length - 1) As Byte
        encryptedStream.Read(result, 0, encryptedStream.Length)
        cryptStream.Close()
        'Dim myutf As UTF8Encoding = New UTF8Encoding()
        'Return myutf.GetString(result)
        Return result
    End Function
 
    Public Function Decrypt(ByVal inputInBytes() As Byte) As String
        ' UTFEncoding is used to transform the decrypted Byte Array
        ' information back into a string.
        Dim myutf As UTF8Encoding = New UTF8Encoding()
 
        'Dim inputInBytes() As Byte = myutf.GetBytes(input)
 
        Dim utf8encoder As UTF8Encoding = New UTF8Encoding()
        Dim tdesProvider As TripleDESCryptoServiceProvider = New TripleDESCryptoServiceProvider()
 
        ' As before we must provide the encryption/decryption key along with
        ' the init vector.
        Dim cryptoTransform As ICryptoTransform = tdesProvider.CreateDecryptor(Me.key, Me.iv)
 
        ' Provide a memory stream to decrypt information into
        Dim decryptedStream As MemoryStream = New MemoryStream()
        Dim cryptStream As CryptoStream = New CryptoStream(decryptedStream, cryptoTransform, CryptoStreamMode.Write)
        cryptStream.Write(inputInBytes, 0, inputInBytes.Length)
        cryptStream.FlushFinalBlock()
        decryptedStream.Position = 0
 
        ' Read the memory stream and convert it back into a string
        Dim result(decryptedStream.Length - 1) As Byte
        decryptedStream.Read(result, 0, decryptedStream.Length)
        cryptStream.Close()
        Return myutf.GetString(result)
    End Function
End Class
 
 
 
Public NotInheritable Class Encryption
 
    Private TripleDes As New TripleDESCryptoServiceProvider
 
    Private svKey As String = "justsomewordstobeusedasacryptionkey"
 
    Sub New(ByVal key As String)
 
        ' Initialize the crypto provider.
 
        TripleDes.Key = TruncateHash(key, TripleDes.KeySize \ 8)
 
        TripleDes.IV = TruncateHash("", TripleDes.BlockSize \ 8)
 
    End Sub
 
    Sub New()
 
        TripleDes.Key = TruncateHash(svKey, TripleDes.KeySize \ 8)
 
        TripleDes.IV = TruncateHash("", TripleDes.BlockSize \ 8)
 
    End Sub
 
    Private Function TruncateHash(ByVal key As String, ByVal length As Integer) As Byte()
 
        Dim sha1 As New SHA1CryptoServiceProvider
 
        ' Hash the key.
 
        Dim keyBytes() As Byte = System.Text.Encoding.Unicode.GetBytes(key)
 
        Dim hash() As Byte = sha1.ComputeHash(keyBytes)
 
        ' Truncate or pad the hash.
 
        ReDim Preserve hash(length - 1)
 
        Return hash
 
    End Function
 
    Public Function EncryptData(ByVal plaintext As String) As String
 
        ' Convert the plaintext string to a byte array.
 
        Dim plaintextBytes() As Byte = System.Text.Encoding.Unicode.GetBytes(plaintext)
 
        ' Create the stream.
 
        Dim ms As New System.IO.MemoryStream
 
        ' Create the encoder to write to the stream.
 
        Dim encStream As New CryptoStream(ms, TripleDes.CreateEncryptor(), System.Security.Cryptography.CryptoStreamMode.Write)
 
        ' Use the crypto stream to write the byte array to the stream.
 
        encStream.Write(plaintextBytes, 0, plaintextBytes.Length)
 
        encStream.FlushFinalBlock()
 
        ' Convert the encrypted stream to a printable string.
 
        Return Convert.ToBase64String(ms.ToArray)
 
    End Function
 
    Public Function DecryptData(ByVal encryptedtext As String) As String
 
        ' Convert the encrypted text string to a byte array.
 
        Dim encryptedBytes() As Byte = Convert.FromBase64String(encryptedtext)
 
        ' Create the stream.
 
        Dim ms As New System.IO.MemoryStream
 
        ' Create the decoder to write to the stream.
 
        Dim decStream As New CryptoStream(ms, TripleDes.CreateDecryptor(), System.Security.Cryptography.CryptoStreamMode.Write)
 
        ' Use the crypto stream to write the byte array to the stream.
 
        decStream.Write(encryptedBytes, 0, encryptedBytes.Length)
 
        decStream.FlushFinalBlock()
 
        ' Convert the plaintext stream to a string.
 
        Return System.Text.Encoding.Unicode.GetString(ms.ToArray)
 
    End Function
 
End Class

                                              
1:
2:
3:
4:
5:
6:
7:
8:
9:
10:
11:
12:
13:
14:
15:
16:
17:
18:
19:
20:
21:
22:
23:
24:
25:
26:
27:
28:
29:
30:
31:
32:
33:
34:
35:
36:
37:
38:
39:
40:
41:
42:
43:
44:
45:
46:
47:
48:
49:
50:
51:
52:
53:
54:
55:
56:
57:
58:
59:
60:
61:
62:
63:
64:
65:
66:
67:
68:
69:
70:
71:
72:
73:
74:
75:
76:
77:
78:
79:
80:
81:
82:
83:
84:
85:
86:
87:
88:
89:
90:
91:
92:
93:
94:
95:
96:
97:
98:
99:
100:
101:
102:
103:
104:
105:
106:
107:
108:
109:
110:
111:
112:
113:
114:
115:
116:
117:
118:
119:
120:
121:
122:
123:
124:
125:
126:
127:
128:
129:
130:
131:
132:
133:
134:
135:
136:
137:
138:
139:
140:
141:
142:
143:
144:
145:
146:
147:
148:
149:
150:
151:
152:
153:
154:
155:
156:
157:
158:
159:
160:
161:
162:
163:
164:
165:
166:
167:
168:
169:
170:
171:

Select allOpen in new window

 

by: jazz__manPosted on 2009-10-12 at 08:01:39ID: 25551818

Here is a nice simple soloution for you and I have tested it for you .....

First simply create the class

Imports System.Security.Cryptography
Imports System.IO

Public Class Encryptor
   'Supported .Net intrinsic SymmetricAlgorithm classes.
   Public Enum Providers
       [DES]
       [RC2]
       [Rijndael]
   End Enum

   Private _CryptoService As SymmetricAlgorithm

   'Constructor for using an intrinsic .Net SymmetricAlgorithm class.
   Public Sub New(ByVal NetSelected As Providers)
       Select Case NetSelected
           Case Providers.DES
               _CryptoService = New DESCryptoServiceProvider
           Case Providers.RC2
               _CryptoService = New RC2CryptoServiceProvider
           Case Providers.Rijndael
               _CryptoService = New RijndaelManaged
       End Select
   End Sub

   'Constructor for using a customized SymmetricAlgorithm class.
   Public Sub New(ByVal ServiceProvider As SymmetricAlgorithm)
       _CryptoService = ServiceProvider
   End Sub

   'Depending on the legal key size limitations of a specific CryptoService provider
   'and length of the private key provided, padding the secret key with space character
   'to meet the legal size of the algorithm.
   Private Function GetLegalKey(ByVal Key As String) As Byte()
       Dim sTemp As String
       If (_CryptoService.LegalKeySizes.Length > 0) Then
           Dim lessSize As Integer = 0
           Dim moreSize As Integer = _CryptoService.LegalKeySizes(0).MinSize
           'key sizes are in bits
           Do While (Key.Length * 8 > moreSize)
               lessSize = moreSize
               moreSize += _CryptoService.LegalKeySizes(0).SkipSize
           Loop
           sTemp = Key.PadRight(moreSize / 8, " ")
       Else
           sTemp = Key
       End If

       'convert the secret key to byte array
       Return ASCIIEncoding.ASCII.GetBytes(sTemp)
   End Function

   Public Function Encrypt(ByVal Source As String, ByVal Key As String) As String
       Dim bytIn As Byte() = System.Text.ASCIIEncoding.ASCII.GetBytes(Source)
       'create a MemoryStream so that the process can be done without I/O files
       Dim ms As MemoryStream = New MemoryStream

       Dim bytKey As Byte() = GetLegalKey(Key)

       'set the private key
       _CryptoService.Key = bytKey
       _CryptoService.IV = bytKey

       'create an Encryptor from the Provider Service instance
       Dim encrypto As ICryptoTransform = _CryptoService.CreateEncryptor()

       'create Crypto Stream that transforms a stream using the encryption
       Dim cs As CryptoStream = New CryptoStream(ms, encrypto, CryptoStreamMode.Write)

       'write out encrypted content into MemoryStream
       cs.Write(bytIn, 0, bytIn.Length)
       cs.FlushFinalBlock()

       'get the output and trim the '\0' bytes
       Dim bytOut As Byte() = ms.GetBuffer()
       Dim i As Integer = 0
       For i = 0 To bytOut.Length
           If bytOut(i) = 0 Then Exit For
       Next

       'convert into Base64 so that the result can be used in xml
       Return System.Convert.ToBase64String(bytOut, 0, i)
   End Function

   Public Function Decrypt(ByVal Source As String, ByVal Key As String) As String
       'convert from Base64 to binary
       Dim bytIn As Byte() = System.Convert.FromBase64String(Source)
       'create a MemoryStream with the input
       Dim ms As MemoryStream = New MemoryStream(bytIn, 0, bytIn.Length)

       Dim bytKey As Byte() = GetLegalKey(Key)

       'set the private key
       _CryptoService.Key = bytKey
       _CryptoService.IV = bytKey

       'create a Decryptor from the Provider Service instance
       Dim encrypto As ICryptoTransform = _CryptoService.CreateDecryptor()

       'create Crypto Stream that transforms a stream using the decryption
       Dim cs As CryptoStream = New CryptoStream(ms, encrypto, CryptoStreamMode.Read)

       'read out the result from the Crypto Stream
       Dim sr As StreamReader = New StreamReader(cs)
       Return sr.ReadToEnd()
   End Function

End Class




Once you have created this class, you can use it like this....


Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
       Dim EncMyWorld As String = EncryptString("MyWorld")
       Dim DecMyWorld As String = DecryptString(EncMyWorld)
   End Sub '***********Put a break point here and you can examine both encrypted and decrypted values************

   Private Function EncryptString(ByVal StringValue As String) As String
       Dim Enc As New Encryptor(Encryptor.Providers.DES)

       Dim MyWorld As String = StringValue

       Dim EncryptedMyWorld As String = Enc.Encrypt(MyWorld, "MyWorld")

       Return EncryptedMyWorld
   End Function

   Private Function DecryptString(ByVal EncryptedStringValue As String) As String
       Dim Enc As New Encryptor(Encryptor.Providers.DES)
       Dim EncMyWorld As String = EncryptedStringValue

       Dim DecryptedMyWorld As String = Enc.Decrypt(EncMyWorld, "MyWorld")

       Return DecryptedMyWorld
   End Function


I trust this will be helpful

Kind Regards...



 

by: jazz__manPosted on 2009-10-12 at 08:03:15ID: 25551832

Also note you have three different options in which to encrypt your srings...

eg

Public Enum Providers
       [DES]
       [RC2]
       [Rijndael]
   End Enum

Cheers

 

by: CraigLazarPosted on 2009-10-16 at 01:16:15ID: 25587703

Hi Guys,

thanks allot for the input, things have been manic and i will be able to get to this first thing next week.

thanks again

cheers

 

by: jazz__manPosted on 2009-10-16 at 01:23:18ID: 25587717

No problem CraigLazar take your time.

The code I have posted has been tested in vs 2008 and so it should just be a quick and simple copy/paste procedure and you will be up and running.

Kind Regards

Paul

 

by: CraigLazarPosted on 2009-10-20 at 21:04:45ID: 25620746

Hi Guys,
thanks allot for the help, really appreciate it


cheers

20120131-EE-VQP-002

3 Ways to Join

30-Day Free Trial

The Experts

98% positive feedback on 31,087 answers since March 2000. angeliii is a Microsoft Most Valuable Professional for his work with MS SQL Server & Develoment.

He has also proven his knowledge of Visual Basic Programming, PHP Scripting and Oracle Databases.

The Experts

97% positive feedback on 10,752 answers since July 2000. lrmoore has more than 18 years experience in the networking industry.

The six-time Mircosoft MVPs specialties include firewalls, virtual private networking, and network management.

Testimonials

"...and excellent source for support... Kind of like having your very own IT dept." Electriciansnet

Testimonials

"I was apprehensive at signing up at first. However... it has already made my life as an IT administrator much easier." JaCrews

Testimonials

"WOW! You guys have great, active, and knowledgeable people on here." moore50

Business Clients

Business Clients

In the Press

"If you’ve got a question... Experts Exchange can supply an answer.”

In the Press

"...an invaluable aid for both IT professionals and those who require tech support."

In the Press

"where IT professionals provide quick answers on just about any topic"

Business Account Plans

Loading Advertisement...