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HashAlgorithm.ComputeHash Method (Stream)

Computes the hash value for the specified Stream object.

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

public byte[] ComputeHash(
	Stream inputStream
)

Parameters

inputStream
Type: System.IO.Stream

The input to compute the hash code for.

Return Value

Type: System.Byte[]
The computed hash code.

ExceptionCondition
ObjectDisposedException

The object has already been disposed.

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

using System;
using System.IO;
using System.Security.Cryptography;
using System.Windows.Forms;

public class HashDirectory
{

    [STAThreadAttribute]
    public static void Main(String[] args)
    {
        string directory = "";
        if (args.Length < 1)
        {
            FolderBrowserDialog fbd = new FolderBrowserDialog();
            DialogResult dr = fbd.ShowDialog();
            if (dr == DialogResult.OK)
                directory = fbd.SelectedPath;
            else
            {
                Console.WriteLine("No directory selected.");
                return;
            }
        }
        else
            directory = args[0];
        try
        {
            // Create a DirectoryInfo object representing the specified directory.
            DirectoryInfo dir = new DirectoryInfo(directory);
            // Get the FileInfo objects for every file in the directory.
            FileInfo[] files = dir.GetFiles();
            // Initialize a RIPE160 hash object.
            RIPEMD160 myRIPEMD160 = RIPEMD160Managed.Create();
            byte[] hashValue;
            // Compute and print the hash values for each file in directory. 
            foreach (FileInfo fInfo in files)
            {
                // Create a fileStream for the file.
                FileStream 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();
            }
            return;
        }
        catch (DirectoryNotFoundException)
        {
            Console.WriteLine("Error: The directory specified could not be found.");
        }
        catch (IOException)
        {
            Console.WriteLine("Error: A file in the directory could not be accessed.");
        }
    }
    // Print the byte array in a readable format. 
    public static void PrintByteArray(byte[] array)
    {
        int i;
        for (i = 0; i < array.Length; i++)
        {
            Console.Write(String.Format("{0:X2}", array[i]));
            if ((i % 4) == 3) Console.Write(" ");
        }
        Console.WriteLine();
    }
}

.NET Framework

Supported in: 4.5.3, 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Supported in: Windows Phone 8.1

Supported in: Windows Phone Silverlight 8.1

Supported in: Windows Phone Silverlight 8

Windows Phone 8.1, Windows Phone 8, Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

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

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