SHA256Managed SHA256Managed SHA256Managed SHA256Managed Class

Definition

Computes the SHA256 hash for the input data using the managed library.

public ref class SHA256Managed : System::Security::Cryptography::SHA256
[System.Runtime.InteropServices.ComVisible(true)]
public class SHA256Managed : System.Security.Cryptography.SHA256
type SHA256Managed = class
    inherit SHA256
Public Class SHA256Managed
Inherits SHA256
Inheritance
Attributes

Examples

The following example calculates the SHA-256 hash for all files in a directory.

using namespace System;
using namespace System::IO;
using namespace System::Security::Cryptography;

// Print the byte array in a readable format.
void PrintByteArray( array<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();
}

int main()
{
   array<String^>^args = Environment::GetCommandLineArgs();
   if ( args->Length < 2 )
   {
      Console::WriteLine( "Usage: hashdir <directory>" );
      return 0;
   }

   try
   {

      // Create a DirectoryInfo object representing the specified directory.
      DirectoryInfo^ dir = gcnew DirectoryInfo( args[ 1 ] );

      // Get the FileInfo objects for every file in the directory.
      array<FileInfo^>^files = dir->GetFiles();

      // Initialize a SHA256 hash object.
      SHA256 ^ mySHA256 = SHA256Managed::Create();
      array<Byte>^hashValue;

      // Compute and print the hash values for each file in directory.
      System::Collections::IEnumerator^ myEnum = files->GetEnumerator();
      while ( myEnum->MoveNext() )
      {
         FileInfo^ fInfo = safe_cast<FileInfo^>(myEnum->Current);

         // Create a fileStream for the file.
         FileStream^ fileStream = fInfo->Open( FileMode::Open );

         // Compute the hash of the fileStream.
         hashValue = mySHA256->ComputeHash( fileStream );

         // Write the name of the file to the Console.
         Console::Write( "{0}: ", fInfo->Name );

         // Write the hash value to the Console.
         PrintByteArray( hashValue );

         // Close the file.
         fileStream->Close();
      }
      return 0;
   }
   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." );
   }

}
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 SHA256 hash object.
            SHA256 mySHA256 = SHA256Managed.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 = mySHA256.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();
    }
}
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 SHA256 hash object.
            Dim mySHA256 As SHA256 = SHA256Managed.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 = mySHA256.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

Remarks

The hash is used as a unique value of fixed size representing a large amount of data. Hashes of two sets of data should match if and only if the corresponding data also matches. Small changes to the data result in large unpredictable changes in the hash.

The hash size for the SHA256Managed algorithm is 256 bits.

Constructors

SHA256Managed() SHA256Managed() SHA256Managed() SHA256Managed()

Initializes a new instance of the SHA256Managed class using the managed library.

Methods

Clear() Clear() Clear() Clear()

Releases all resources used by the HashAlgorithm class.

(Inherited from HashAlgorithm)
ComputeHash(Byte[]) ComputeHash(Byte[]) ComputeHash(Byte[]) ComputeHash(Byte[])

Computes the hash value for the specified byte array.

(Inherited from HashAlgorithm)
ComputeHash(Byte[], Int32, Int32) ComputeHash(Byte[], Int32, Int32) ComputeHash(Byte[], Int32, Int32) ComputeHash(Byte[], Int32, Int32)

Computes the hash value for the specified region of the specified byte array.

(Inherited from HashAlgorithm)
ComputeHash(Stream) ComputeHash(Stream) ComputeHash(Stream) ComputeHash(Stream)

Computes the hash value for the specified Stream object.

(Inherited from HashAlgorithm)
Dispose() Dispose() Dispose() Dispose()

Releases all resources used by the current instance of the HashAlgorithm class.

(Inherited from HashAlgorithm)
Dispose(Boolean) Dispose(Boolean) Dispose(Boolean) Dispose(Boolean)
Equals(Object) Equals(Object) Equals(Object) Equals(Object)

Determines whether the specified object is equal to the current object.

(Inherited from Object)
Finalize() Finalize() Finalize() Finalize()
GetHashCode() GetHashCode() GetHashCode() GetHashCode()

Serves as the default hash function.

(Inherited from Object)
GetType() GetType() GetType() GetType()

Gets the Type of the current instance.

(Inherited from Object)
HashCore(Byte[], Byte[], Int32, Int32) HashCore(Byte[], Byte[], Int32, Int32) HashCore(Byte[], Byte[], Int32, Int32) HashCore(Byte[], Byte[], Int32, Int32)

When overridden in a derived class, routes data written to the object into the SHA256 hash algorithm for computing the hash.

HashCore(Byte[], Int32, Int32) HashCore(Byte[], Int32, Int32) HashCore(Byte[], Int32, Int32) HashCore(Byte[], Int32, Int32)

When overridden in a derived class, routes data written to the object into the hash algorithm for computing the hash.

(Inherited from HashAlgorithm)
HashCore(ReadOnlySpan<Byte>) HashCore(ReadOnlySpan<Byte>) HashCore(ReadOnlySpan<Byte>) HashCore(ReadOnlySpan<Byte>)
HashFinal() HashFinal() HashFinal() HashFinal()

When overridden in a derived class, finalizes the hash computation after the last data is processed by the cryptographic stream object.

Initialize() Initialize() Initialize() Initialize()

Initializes an instance of SHA256Managed.

MemberwiseClone() MemberwiseClone() MemberwiseClone() MemberwiseClone()

Creates a shallow copy of the current Object.

(Inherited from Object)
ToString() ToString() ToString() ToString()

Returns a string that represents the current object.

(Inherited from Object)
TransformBlock(Byte[], Int32, Int32, Byte[], Int32) TransformBlock(Byte[], Int32, Int32, Byte[], Int32) TransformBlock(Byte[], Int32, Int32, Byte[], Int32) TransformBlock(Byte[], Int32, Int32, Byte[], Int32)

Computes the hash value for the specified region of the input byte array and copies the specified region of the input byte array to the specified region of the output byte array.

(Inherited from HashAlgorithm)
TransformFinalBlock(Byte[], Int32, Int32) TransformFinalBlock(Byte[], Int32, Int32) TransformFinalBlock(Byte[], Int32, Int32) TransformFinalBlock(Byte[], Int32, Int32)

Computes the hash value for the specified region of the specified byte array.

(Inherited from HashAlgorithm)
TryComputeHash(ReadOnlySpan<Byte>, Span<Byte>, Int32) TryComputeHash(ReadOnlySpan<Byte>, Span<Byte>, Int32) TryComputeHash(ReadOnlySpan<Byte>, Span<Byte>, Int32) TryComputeHash(ReadOnlySpan<Byte>, Span<Byte>, Int32) Inherited from HashAlgorithm
TryHashFinal(Span<Byte>, Int32) TryHashFinal(Span<Byte>, Int32) TryHashFinal(Span<Byte>, Int32) TryHashFinal(Span<Byte>, Int32)

Properties

CanReuseTransform CanReuseTransform CanReuseTransform CanReuseTransform

Gets a value indicating whether the current transform can be reused.

(Inherited from HashAlgorithm)
CanTransformMultipleBlocks CanTransformMultipleBlocks CanTransformMultipleBlocks CanTransformMultipleBlocks

When overridden in a derived class, gets a value indicating whether multiple blocks can be transformed.

(Inherited from HashAlgorithm)
Hash Hash Hash Hash

Gets the value of the computed hash code.

(Inherited from HashAlgorithm)
HashSize HashSize HashSize HashSize

Gets the size, in bits, of the computed hash code.

(Inherited from HashAlgorithm)
InputBlockSize InputBlockSize InputBlockSize InputBlockSize

When overridden in a derived class, gets the input block size.

(Inherited from HashAlgorithm)
OutputBlockSize OutputBlockSize OutputBlockSize OutputBlockSize

When overridden in a derived class, gets the output block size.

(Inherited from HashAlgorithm)

Fields

HashSizeValue HashSizeValue HashSizeValue HashSizeValue

Represents the size, in bits, of the computed hash code.

(Inherited from HashAlgorithm)
HashValue HashValue HashValue HashValue

Represents the value of the computed hash code.

(Inherited from HashAlgorithm)
State State State State

Represents the state of the hash computation.

(Inherited from HashAlgorithm)

Explicit Interface Implementations

IDisposable.Dispose() IDisposable.Dispose() IDisposable.Dispose() IDisposable.Dispose() Inherited from HashAlgorithm

Applies to