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RIPEMD160 Class
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RIPEMD160 Class

Updated: February 2009

Represents the abstract class from which all implementations of the MD160 hash algorithm inherit.

Namespace:  System.Security.Cryptography
Assembly:  mscorlib (in mscorlib.dll)

'Declaration
<ComVisibleAttribute(True)> _
Public MustInherit Class RIPEMD160 _
	Inherits HashAlgorithm
'Usage
Dim instance As RIPEMD160

Hash functions map binary strings of an arbitrary length to small binary strings of a fixed length. A cryptographic hash function has the property that it is computationally infeasible to find two distinct inputs that hash to the same value; that is, hashes of two sets of data should match if the corresponding data also matches. Small changes to the data result in large unpredictable changes in the hash.

RIPEMD-160 is a 160-bit cryptographic hash function. It is intended for use as a replacement for the 128-bit hash functions MD4, MD5, and RIPEMD. RIPEMD was developed in the framework of the EU project RIPE (RACE Integrity Primitives Evaluation, 1988-1992).

NoteNote:

Newer hash functions, such as the Secure Hash Algorithms SHA-256 and SHA-512, are available. Consider using the SHA256 class or the SHA512 class instead of the RIPEMD160 class.

The following code example calculates the RIPEMD160 hash for all files in a directory.

Imports System
Imports System.IO
Imports System.Security.Cryptography
Imports System.Windows.Forms

Public Class HashDirectory

    Public Shared Sub Main(ByVal args() As String)
        Dim directory As String 
        If args.Length < 1 Then 
            Dim fdb As New FolderBrowserDialog
            Dim dr As DialogResult = fdb.ShowDialog()
            If (dr = DialogResult.OK) Then
                directory = fdb.SelectedPath
            Else
                Console.WriteLine("No directory selected")
                Return 
            End If 
        Else
            directory = args(0)
        End If 
        Try 
            ' Create a DirectoryInfo object representing the specified directory. 
            Dim dir As New DirectoryInfo(directory)
            ' Get the FileInfo objects for every file in the directory. 
            Dim files As FileInfo() = dir.GetFiles()
            ' Initialize a RIPE160 hash object. 
            Dim myRIPEMD160 As RIPEMD160 = RIPEMD160Managed.Create()
            Dim hashValue() As Byte
            ' Compute and print the hash values for each file in directory. 
            Dim fInfo As FileInfo
            For Each fInfo In files
                ' Create a fileStream for the file. 
                Dim fileStream As FileStream = fInfo.Open(FileMode.Open)
                ' Be sure it's positioned to the beginning of the stream.
                fileStream.Position = 0
                ' Compute the hash of the fileStream.
                hashValue = myRIPEMD160.ComputeHash(fileStream)
                ' Write the name of the file to the Console.
                Console.Write(fInfo.Name + ": ")
                ' Write the hash value to the Console.
                PrintByteArray(hashValue)
                ' Close the file.
                fileStream.Close()
            Next fInfo
            Return 
        Catch DExc As DirectoryNotFoundException
            Console.WriteLine("Error: The directory specified could not be found.")
        Catch IOExc As IOException
            Console.WriteLine("Error: A file in the directory could not be accessed.")
        End Try 

    End Sub 

    ' Print the byte array in a readable format. 
    Public Shared Sub PrintByteArray(ByVal array() As Byte)
        Dim i As Integer 
        For i = 0 To array.Length - 1
            Console.Write(String.Format("{0:X2}", array(i)))
            If i Mod 4 = 3 Then
                Console.Write(" ")
            End If 
        Next i
        Console.WriteLine()

    End Sub 'PrintByteArray
End Class

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 3.5, 3.0, 2.0

Date

History

Reason

February 2009

Added note about newer hash functions SHA-256 and SHA-512.

Information enhancement.

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