RIPEMD160Managed Costruttore

Definizione

Spazio dei nomi:

System.Security.Cryptography

Assembly:

mscorlib.dll

Inizializza una nuova istanza della classe RIPEMD160.

public:
 RIPEMD160Managed();

public RIPEMD160Managed ();

Public Sub New ()

Eccezioni

InvalidOperationException

I criteri non sono conformi all'algoritmo FIPS.

Esempio

Nell'esempio di codice seguente viene calcolato l'hash della RIPEMD160Managed classe per tutti i file in una 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 RIPE160 hash object.
      RIPEMD160 ^ myRIPEMD160 = RIPEMD160Managed::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 = myRIPEMD160->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 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();
    }
}

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
End Class

Commenti

L'hash viene usato come valore univoco di dimensioni fisse che rappresentano una grande quantità di dati. Gli hash di due set di dati devono corrispondere se e solo se i dati corrispondenti corrispondono anche. Le piccole modifiche apportate ai dati comportano modifiche imprevedibili di grandi dimensioni nell'hash.

Le dimensioni hash per l'algoritmo RIPEMD160 sono 160 bit.

Vedi anche

• servizi crittografici