HMACRIPEMD160 コンストラクタ

.NET Framework クラス ライブラリ リファレンス

HMACRIPEMD160 コンストラクタ (Byte[])

メモ : このコンストラクタは、.NET Framework version 2.0 で新しく追加されたものです。

キー データを指定して、HMACRIPEMD160 クラスの新しいインスタンスを初期化します。

名前空間: System.Security.Cryptography
アセンブリ: mscorlib (mscorlib.dll 内)
構文

Visual Basic (宣言)

Public Sub New ( _
    key As Byte() _
)

Visual Basic (使用法)

Dim key As Byte()

Dim instance As New HMACRIPEMD160(key)

C#

public HMACRIPEMD160 (
    byte[] key
)

C++

public:
HMACRIPEMD160 (
    array<unsigned char>^ key
)

J#

public HMACRIPEMD160 (
    byte[] key
)

JScript

public function HMACRIPEMD160 (
    key : byte[]
)

パラメータ

key

HMACRIPEMD160 暗号化の共有キー。キーは任意の長さにできますが、64 バイトを超えた場合は、SHA-1 を使用してハッシュされ、最終的には 64 バイトのキーが生成されます。したがって、共有キーの推奨サイズは 64 バイトです。

例外

例外の種類	条件
ArgumentNullException	key パラメータが null 参照 (Visual Basic では Nothing) です。

解説

HMACRIPEMD160 は、RIPEMD160 ハッシュ関数から構築され、ハッシュ メッセージ認証コード (HMAC) として使用されるキー付きハッシュ アルゴリズムの一種です。HMAC プロセスでは、共有キーとメッセージ データを合成して、その結果にハッシュ関数を適用し、ハッシュ値と共有キーを再び合成した上で、もう一度ハッシュ関数を適用します。出力されるハッシュは 160 バイト長になります。

使用例

HMACRIPEMD160 を使用してファイルをエンコードしたり、エンコード済みのファイルをデコードしたりする方法を次のコード例に示します。

C#

using System;
using System.IO;
using System.Security.Cryptography;

public class HMACRIPEMD160example
{
    // Computes a keyed hash for a source file, creates a target file
 with the keyed hash
    // prepended to the contents of the source file, then decrypts the
 file and compares
    // the source and the decrypted files.
    public static void EncodeFile(byte[]
 key, String sourceFile, String destFile)
    {
        // Initialize the keyed hash object.
        HMACRIPEMD160 myhmacRIPEMD160 = new HMACRIPEMD160(key);
        FileStream inStream = new FileStream(sourceFile, FileMode.Open);
        FileStream outStream = new FileStream(destFile, FileMode.Create);
        // Compute the hash of the input file.
        byte[] hashValue = myhmacRIPEMD160.ComputeHash(inStream);
        // Reset inStream to the beginning of the file.
        inStream.Position = 0;
        // Write the computed hash value to the output file.
        outStream.Write(hashValue, 0, hashValue.Length);
        // Copy the contents of the sourceFile to the destFile.
        int bytesRead;
        // read 1K at a time
        byte[] buffer = new byte[1024]; 
        do
        {
            // Read from the wrapping CryptoStream.
            bytesRead = inStream.Read(buffer,0,1024); 
            outStream.Write(buffer, 0, bytesRead);
        } while (bytesRead > 0); 
        myhmacRIPEMD160.Clear();
        // Close the streams
        inStream.Close();
        outStream.Close();
        return;
    } // end EncodeFile


    // Decrypt the encoded file and compare to original file.
    public static bool DecodeFile(byte[]
 key, String sourceFile)
    {
        // Initialize the keyed hash object. 
        HMACRIPEMD160 hmacRIPEMD160 = new HMACRIPEMD160(key);
        // Create an array to hold the keyed hash value read from the
 file.
        byte[] storedHash = new byte[hmacRIPEMD160.HashSize/8];
        // Create a FileStream for the source file.
        FileStream inStream = new FileStream(sourceFile, FileMode.Open);
        // Read in the storedHash.
        inStream.Read(storedHash, 0, storedHash.Length);
        // Compute the hash of the remaining contents of the file.
        // The stream is properly positioned at the beginning of the
 content, 
        // immediately after the stored hash value.
        byte[] computedHash = hmacRIPEMD160.ComputeHash(inStream);
        // compare the computed hash with the stored value
        for (int i =0; i < storedHash.Length;
 i++)
        {
            if (computedHash[i] != storedHash[i])
            {
                Console.WriteLine("Hash values differ! Encoded file has been
 tampered with!");
                return false;
            }
        }
        Console.WriteLine("Hash values agree -- no tampering occurred.");
        return true;
    } //end DecodeFile

    private const string
 usageText = "Usage: HMACRIPEMD160 inputfile.txt encryptedfile.hsh\nYou must
 specify the two file names. Only the first file must exist.\n";
    public static void Main(string[]
 Fileargs)
    {
        //If no file names are specified, write usage text.
        if (Fileargs.Length < 2)
        {
            Console.WriteLine(usageText);
        }
        else
        {
            try
            {
                // Create a random key using a random number generator.
 This would be the
                //  secret key shared by sender and receiver.
                byte[] secretkey = new Byte[64];
                //RNGCryptoServiceProvider is an implementation of a
 random number generator.
                RNGCryptoServiceProvider rng = new RNGCryptoServiceProvider();
                // The array is now filled with cryptographically strong
 random bytes.
                rng.GetBytes(secretkey); 

                // Use the secret key to encode the message file.
                EncodeFile(secretkey, Fileargs[0], Fileargs[1]);

                // Take the encoded file and decode
                DecodeFile(secretkey, Fileargs[1]);
            }
            catch (IOException e)
            {
                Console.WriteLine("Error: File not found",e);
            }
        } //end if-else

    }  //end main
} //end class

C++

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

// Computes a keyed hash for a source file, creates a target file with
 the keyed hash
// prepended to the contents of the source file, then decrypts the file
 and compares
// the source and the decrypted files.
void EncodeFile( array<Byte>^key, String^ sourceFile, String^
 destFile )
{
   
   // Initialize the keyed hash object.
   HMACRIPEMD160^ myhmacRIPEMD160 = gcnew HMACRIPEMD160( key );
   FileStream^ inStream = gcnew FileStream( sourceFile,FileMode::Open );
   FileStream^ outStream = gcnew FileStream( destFile,FileMode::Create );
   
   // Compute the hash of the input file.
   array<Byte>^hashValue = myhmacRIPEMD160->ComputeHash( inStream );
   
   // Reset inStream to the beginning of the file.
   inStream->Position = 0;
   
   // Write the computed hash value to the output file.
   outStream->Write( hashValue, 0, hashValue->Length );
   
   // Copy the contents of the sourceFile to the destFile.
   int bytesRead;
   
   // read 1K at a time
   array<Byte>^buffer = gcnew array<Byte>(1024);
   do
   {
      
      // Read from the wrapping CryptoStream.
      bytesRead = inStream->Read( buffer, 0, 1024 );
      outStream->Write( buffer, 0, bytesRead );
   }
   while ( bytesRead > 0 );

   myhmacRIPEMD160->Clear();
   
   // Close the streams
   inStream->Close();
   outStream->Close();
   return;
} // end EncodeFile



// Decrypt the encoded file and compare to original file.
bool DecodeFile( array<Byte>^key, String^ sourceFile )
{
   
   // Initialize the keyed hash object. 
   HMACRIPEMD160^ hmacRIPEMD160 = gcnew HMACRIPEMD160( key );
   
   // Create an array to hold the keyed hash value read from the file.
   array<Byte>^storedHash = gcnew array<Byte>(hmacRIPEMD160->HashSize
 / 8);
   
   // Create a FileStream for the source file.
   FileStream^ inStream = gcnew FileStream( sourceFile,FileMode::Open );
   
   // Read in the storedHash.
   inStream->Read( storedHash, 0, storedHash->Length );
   
   // Compute the hash of the remaining contents of the file.
   // The stream is properly positioned at the beginning of the content,
 
   // immediately after the stored hash value.
   array<Byte>^computedHash = hmacRIPEMD160->ComputeHash( inStream );
   
   // compare the computed hash with the stored value
   for ( int i = 0; i < storedHash->Length;
 i++ )
   {
      if ( computedHash[ i ] != storedHash[ i ] )
      {
         Console::WriteLine( "Hash values differ! Encoded file has been tampered
 with!" );
         return false;
      }

   }
   Console::WriteLine( "Hash values agree -- no tampering occurred." );
   return true;
} //end DecodeFile


int main()
{
   array<String^>^Fileargs = Environment::GetCommandLineArgs();
   String^ usageText = "Usage: HMACRIPEMD160 inputfile.txt encryptedfile.hsh\nYou
 must specify the two file names. Only the first file must exist.\n";
   
   //If no file names are specified, write usage text.
   if ( Fileargs->Length < 3 )
   {
      Console::WriteLine( usageText );
   }
   else
   {
      try
      {
         
         // Create a random key using a random number generator. This
 would be the
         //  secret key shared by sender and receiver.
         array<Byte>^secretkey = gcnew array<Byte>(64);
         
         //RNGCryptoServiceProvider is an implementation of a random
 number generator.
         RNGCryptoServiceProvider^ rng = gcnew RNGCryptoServiceProvider;
         
         // The array is now filled with cryptographically strong random
 bytes.
         rng->GetBytes( secretkey );
         
         // Use the secret key to encode the message file.
         EncodeFile( secretkey, Fileargs[ 1 ], Fileargs[ 2 ] );
         
         // Take the encoded file and decode
         DecodeFile( secretkey, Fileargs[ 2 ] );
      }
      catch ( IOException^ e ) 
      {
         Console::WriteLine( "Error: File not found", e );
      }

   }
} //end main

J#

import System.*;
import System.IO.*;
import System.Security.Cryptography.*;

public class HMACRIPEMD160Example
{
    // Computes a keyed hash for a source file, creates a target file
 with the
    //  keyed hash prepended to the contents of the source file, then
 decrypts
    //  the file and compares the source and the decrypted files.
    public static void EncodeFile(ubyte
 key[], String sourceFile, 
        String destFile)
    {
        // Initialize the keyed hash object.
        HMACRIPEMD160 myhmacRIPEMD160 = new HMACRIPEMD160(key);
        FileStream inStream = new FileStream(sourceFile, FileMode.Open);
        FileStream outStream = new FileStream(destFile, FileMode.Create);

        // Compute the hash of the input file.
        ubyte hashValue[] = myhmacRIPEMD160.ComputeHash(inStream);

        // Reset inStream to the beginning of the file.
        inStream.set_Position(0);

        // Write the computed hash value to the output file.
        outStream.Write(hashValue, 0, hashValue.length);

        // Copy the contents of the sourceFile to the destFile.
        int bytesRead;

        // read 1K at a time
        ubyte buffer[] = new ubyte[1024];
        do {
            // Read from the wrapping CryptoStream.
            bytesRead = inStream.Read(buffer, 0, 1024);
            outStream.Write(buffer, 0, bytesRead);
        } while (bytesRead > 0);
        myhmacRIPEMD160.Clear();

        // Close the streams
        inStream.Close();
        outStream.Close();
        return;
    } // end EncodeFile
    
    // Decrypt the encoded file and compare to original file.
    public static boolean DecodeFile(ubyte[]
 key, String sourceFile)
    {
        // Initialize the keyed hash object. 
        HMACRIPEMD160 hmacRIPEMD160 = new HMACRIPEMD160(key);

        // Create an array to hold the keyed hash value read from the
 file.
        ubyte storedHash[] = new ubyte[hmacRIPEMD160.get_HashSize()
 / 8];

        // Create a FileStream for the source file.
        FileStream inStream = new FileStream(sourceFile, FileMode.Open);

        // Read in the storedHash.
        inStream.Read(storedHash, 0, storedHash.length);

        // Compute the hash of the remaining contents of the file.
        // The stream is properly positioned at the beginning of the
 content, 
        // immediately after the stored hash value.
        ubyte computedHash[] = hmacRIPEMD160.ComputeHash(inStream);

        // compare the computed hash with the stored value
        for (int i = 0; i < storedHash.length;
 i++) {
            if (computedHash.get_Item(i) != storedHash.get_Item(i))
 {
                Console.WriteLine("Hash values differ! Encoded file has been"
 
                    + "tampered with!");
                return false;
            }
        }
        Console.WriteLine("Hash values agree -- no tampering occurred.");
        return true;
    } //end DecodeFile

    private static String usageText = "Usage:
 HMACRIPEMD160 inputfile.txt " 
        + "encryptedfile.hsh\nYou must specify the two file names. Only the
 " 
        + " first file must exist.\n";

    public static void main(String[]
 fileargs)
    {
        //If no file names are specified, write usage text.
        if (fileargs.length < 2) {
            Console.WriteLine(usageText);
        }
        else {
            try {
                // Create a random key using a random number generator.
 This 
                // would be the secret key shared by sender and receiver.
                ubyte secretKey[] = new ubyte[64];

                //RNGCryptoServiceProvider is an implementation of a
 random
                // number generator.
                RNGCryptoServiceProvider rng = new RNGCryptoServiceProvider();

                // The array is now filled with cryptographically strong
                // random bytes.
                rng.GetBytes(secretKey);

                // Use the secret key to encode the message file.
                EncodeFile(secretKey, fileargs[0], fileargs[1]);

                // Take the encoded file and decode
                DecodeFile(secretKey, fileargs[1]);
            }
            catch (IOException e) {
                Console.WriteLine("Error: File not found", e);
            }
        }//end if-else
    } //end main
} //end class HMACRIPEMD160Example

プラットフォーム

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

開発プラットフォームの中には、.NET Framework によってサポートされていないバージョンがあります。サポートされているバージョンについては、「システム要件」を参照してください。

バージョン情報

.NET Framework
サポート対象 : 2.0

参照

関連項目
HMACRIPEMD160 クラス
HMACRIPEMD160 メンバ
System.Security.Cryptography 名前空間
その他の技術情報
暗号サービス

HMACRIPEMD160 コンストラクタ

HMACRIPEMD160 クラスの新しいインスタンスを初期化します。
オーバーロードの一覧

名前	説明
HMACRIPEMD160 ()	ランダムに生成された 64 バイトのキーを指定して、HMACRIPEMD160 クラスの新しいインスタンスを初期化します。
HMACRIPEMD160 (Byte[])	キー データを指定して、HMACRIPEMD160 クラスの新しいインスタンスを初期化します。

参照

関連項目

HMACRIPEMD160 クラス
HMACRIPEMD160 メンバ
System.Security.Cryptography 名前空間

その他の技術情報

暗号サービス

HMACRIPEMD160 コンストラクタ ()

メモ : このコンストラクタは、.NET Framework version 2.0 で新しく追加されたものです。

ランダムに生成された 64 バイトのキーを指定して、HMACRIPEMD160 クラスの新しいインスタンスを初期化します。

名前空間: System.Security.Cryptography
アセンブリ: mscorlib (mscorlib.dll 内)
構文

Visual Basic (宣言)

Public Sub New

Visual Basic (使用法)

Dim instance As New HMACRIPEMD160

C#

public HMACRIPEMD160 ()

C++

public:
HMACRIPEMD160 ()

J#

public HMACRIPEMD160 ()

JScript

public function HMACRIPEMD160 ()

解説

HMACRIPEMD160 は、RIPEMD160 ハッシュ関数から構築され、ハッシュ メッセージ認証コード (HMAC) として使用されるキー付きハッシュ アルゴリズムの一種です。HMAC プロセスでは、共有キーとメッセージ データを合成して、その結果にハッシュ関数を適用し、ハッシュ値と共有キーを再び合成した上で、もう一度ハッシュ関数を適用します。出力されるハッシュは 160 バイト長になります。

このコンストラクタでは、64 バイトのランダムに生成されたキーが使用されます。

使用例

HMACRIPEMD160 を使用してファイルをエンコードしたり、エンコード済みのファイルをデコードしたりする方法を次のコード例に示します。

C#

using System;
using System.IO;
using System.Security.Cryptography;

public class HMACRIPEMD160example
{
    // Computes a keyed hash for a source file, creates a target file
 with the keyed hash
    // prepended to the contents of the source file, then decrypts the
 file and compares
    // the source and the decrypted files.
    public static void EncodeFile(byte[]
 key, String sourceFile, String destFile)
    {
        // Initialize the keyed hash object.
        HMACRIPEMD160 myhmacRIPEMD160 = new HMACRIPEMD160(key);
        FileStream inStream = new FileStream(sourceFile, FileMode.Open);
        FileStream outStream = new FileStream(destFile, FileMode.Create);
        // Compute the hash of the input file.
        byte[] hashValue = myhmacRIPEMD160.ComputeHash(inStream);
        // Reset inStream to the beginning of the file.
        inStream.Position = 0;
        // Write the computed hash value to the output file.
        outStream.Write(hashValue, 0, hashValue.Length);
        // Copy the contents of the sourceFile to the destFile.
        int bytesRead;
        // read 1K at a time
        byte[] buffer = new byte[1024]; 
        do
        {
            // Read from the wrapping CryptoStream.
            bytesRead = inStream.Read(buffer,0,1024); 
            outStream.Write(buffer, 0, bytesRead);
        } while (bytesRead > 0); 
        myhmacRIPEMD160.Clear();
        // Close the streams
        inStream.Close();
        outStream.Close();
        return;
    } // end EncodeFile


    // Decrypt the encoded file and compare to original file.
    public static bool DecodeFile(byte[]
 key, String sourceFile)
    {
        // Initialize the keyed hash object. 
        HMACRIPEMD160 hmacRIPEMD160 = new HMACRIPEMD160(key);
        // Create an array to hold the keyed hash value read from the
 file.
        byte[] storedHash = new byte[hmacRIPEMD160.HashSize/8];
        // Create a FileStream for the source file.
        FileStream inStream = new FileStream(sourceFile, FileMode.Open);
        // Read in the storedHash.
        inStream.Read(storedHash, 0, storedHash.Length);
        // Compute the hash of the remaining contents of the file.
        // The stream is properly positioned at the beginning of the
 content, 
        // immediately after the stored hash value.
        byte[] computedHash = hmacRIPEMD160.ComputeHash(inStream);
        // compare the computed hash with the stored value
        for (int i =0; i < storedHash.Length;
 i++)
        {
            if (computedHash[i] != storedHash[i])
            {
                Console.WriteLine("Hash values differ! Encoded file has been
 tampered with!");
                return false;
            }
        }
        Console.WriteLine("Hash values agree -- no tampering occurred.");
        return true;
    } //end DecodeFile

    private const string
 usageText = "Usage: HMACRIPEMD160 inputfile.txt encryptedfile.hsh\nYou must
 specify the two file names. Only the first file must exist.\n";
    public static void Main(string[]
 Fileargs)
    {
        //If no file names are specified, write usage text.
        if (Fileargs.Length < 2)
        {
            Console.WriteLine(usageText);
        }
        else
        {
            try
            {
                // Create a random key using a random number generator.
 This would be the
                //  secret key shared by sender and receiver.
                byte[] secretkey = new Byte[64];
                //RNGCryptoServiceProvider is an implementation of a
 random number generator.
                RNGCryptoServiceProvider rng = new RNGCryptoServiceProvider();
                // The array is now filled with cryptographically strong
 random bytes.
                rng.GetBytes(secretkey); 

                // Use the secret key to encode the message file.
                EncodeFile(secretkey, Fileargs[0], Fileargs[1]);

                // Take the encoded file and decode
                DecodeFile(secretkey, Fileargs[1]);
            }
            catch (IOException e)
            {
                Console.WriteLine("Error: File not found",e);
            }
        } //end if-else

    }  //end main
} //end class

C++

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

// Computes a keyed hash for a source file, creates a target file with
 the keyed hash
// prepended to the contents of the source file, then decrypts the file
 and compares
// the source and the decrypted files.
void EncodeFile( array<Byte>^key, String^ sourceFile, String^
 destFile )
{
   
   // Initialize the keyed hash object.
   HMACRIPEMD160^ myhmacRIPEMD160 = gcnew HMACRIPEMD160( key );
   FileStream^ inStream = gcnew FileStream( sourceFile,FileMode::Open );
   FileStream^ outStream = gcnew FileStream( destFile,FileMode::Create );
   
   // Compute the hash of the input file.
   array<Byte>^hashValue = myhmacRIPEMD160->ComputeHash( inStream );
   
   // Reset inStream to the beginning of the file.
   inStream->Position = 0;
   
   // Write the computed hash value to the output file.
   outStream->Write( hashValue, 0, hashValue->Length );
   
   // Copy the contents of the sourceFile to the destFile.
   int bytesRead;
   
   // read 1K at a time
   array<Byte>^buffer = gcnew array<Byte>(1024);
   do
   {
      
      // Read from the wrapping CryptoStream.
      bytesRead = inStream->Read( buffer, 0, 1024 );
      outStream->Write( buffer, 0, bytesRead );
   }
   while ( bytesRead > 0 );

   myhmacRIPEMD160->Clear();
   
   // Close the streams
   inStream->Close();
   outStream->Close();
   return;
} // end EncodeFile



// Decrypt the encoded file and compare to original file.
bool DecodeFile( array<Byte>^key, String^ sourceFile )
{
   
   // Initialize the keyed hash object. 
   HMACRIPEMD160^ hmacRIPEMD160 = gcnew HMACRIPEMD160( key );
   
   // Create an array to hold the keyed hash value read from the file.
   array<Byte>^storedHash = gcnew array<Byte>(hmacRIPEMD160->HashSize
 / 8);
   
   // Create a FileStream for the source file.
   FileStream^ inStream = gcnew FileStream( sourceFile,FileMode::Open );
   
   // Read in the storedHash.
   inStream->Read( storedHash, 0, storedHash->Length );
   
   // Compute the hash of the remaining contents of the file.
   // The stream is properly positioned at the beginning of the content,
 
   // immediately after the stored hash value.
   array<Byte>^computedHash = hmacRIPEMD160->ComputeHash( inStream );
   
   // compare the computed hash with the stored value
   for ( int i = 0; i < storedHash->Length;
 i++ )
   {
      if ( computedHash[ i ] != storedHash[ i ] )
      {
         Console::WriteLine( "Hash values differ! Encoded file has been tampered
 with!" );
         return false;
      }

   }
   Console::WriteLine( "Hash values agree -- no tampering occurred." );
   return true;
} //end DecodeFile


int main()
{
   array<String^>^Fileargs = Environment::GetCommandLineArgs();
   String^ usageText = "Usage: HMACRIPEMD160 inputfile.txt encryptedfile.hsh\nYou
 must specify the two file names. Only the first file must exist.\n";
   
   //If no file names are specified, write usage text.
   if ( Fileargs->Length < 3 )
   {
      Console::WriteLine( usageText );
   }
   else
   {
      try
      {
         
         // Create a random key using a random number generator. This
 would be the
         //  secret key shared by sender and receiver.
         array<Byte>^secretkey = gcnew array<Byte>(64);
         
         //RNGCryptoServiceProvider is an implementation of a random
 number generator.
         RNGCryptoServiceProvider^ rng = gcnew RNGCryptoServiceProvider;
         
         // The array is now filled with cryptographically strong random
 bytes.
         rng->GetBytes( secretkey );
         
         // Use the secret key to encode the message file.
         EncodeFile( secretkey, Fileargs[ 1 ], Fileargs[ 2 ] );
         
         // Take the encoded file and decode
         DecodeFile( secretkey, Fileargs[ 2 ] );
      }
      catch ( IOException^ e ) 
      {
         Console::WriteLine( "Error: File not found", e );
      }

   }
} //end main

J#

import System.*;
import System.IO.*;
import System.Security.Cryptography.*;

public class HMACRIPEMD160Example
{
    // Computes a keyed hash for a source file, creates a target file
 with the
    //  keyed hash prepended to the contents of the source file, then
 decrypts
    //  the file and compares the source and the decrypted files.
    public static void EncodeFile(ubyte
 key[], String sourceFile, 
        String destFile)
    {
        // Initialize the keyed hash object.
        HMACRIPEMD160 myhmacRIPEMD160 = new HMACRIPEMD160(key);
        FileStream inStream = new FileStream(sourceFile, FileMode.Open);
        FileStream outStream = new FileStream(destFile, FileMode.Create);

        // Compute the hash of the input file.
        ubyte hashValue[] = myhmacRIPEMD160.ComputeHash(inStream);

        // Reset inStream to the beginning of the file.
        inStream.set_Position(0);

        // Write the computed hash value to the output file.
        outStream.Write(hashValue, 0, hashValue.length);

        // Copy the contents of the sourceFile to the destFile.
        int bytesRead;

        // read 1K at a time
        ubyte buffer[] = new ubyte[1024];
        do {
            // Read from the wrapping CryptoStream.
            bytesRead = inStream.Read(buffer, 0, 1024);
            outStream.Write(buffer, 0, bytesRead);
        } while (bytesRead > 0);
        myhmacRIPEMD160.Clear();

        // Close the streams
        inStream.Close();
        outStream.Close();
        return;
    } // end EncodeFile
    
    // Decrypt the encoded file and compare to original file.
    public static boolean DecodeFile(ubyte[]
 key, String sourceFile)
    {
        // Initialize the keyed hash object. 
        HMACRIPEMD160 hmacRIPEMD160 = new HMACRIPEMD160(key);

        // Create an array to hold the keyed hash value read from the
 file.
        ubyte storedHash[] = new ubyte[hmacRIPEMD160.get_HashSize()
 / 8];

        // Create a FileStream for the source file.
        FileStream inStream = new FileStream(sourceFile, FileMode.Open);

        // Read in the storedHash.
        inStream.Read(storedHash, 0, storedHash.length);

        // Compute the hash of the remaining contents of the file.
        // The stream is properly positioned at the beginning of the
 content, 
        // immediately after the stored hash value.
        ubyte computedHash[] = hmacRIPEMD160.ComputeHash(inStream);

        // compare the computed hash with the stored value
        for (int i = 0; i < storedHash.length;
 i++) {
            if (computedHash.get_Item(i) != storedHash.get_Item(i))
 {
                Console.WriteLine("Hash values differ! Encoded file has been"
 
                    + "tampered with!");
                return false;
            }
        }
        Console.WriteLine("Hash values agree -- no tampering occurred.");
        return true;
    } //end DecodeFile

    private static String usageText = "Usage:
 HMACRIPEMD160 inputfile.txt " 
        + "encryptedfile.hsh\nYou must specify the two file names. Only the
 " 
        + " first file must exist.\n";

    public static void main(String[]
 fileargs)
    {
        //If no file names are specified, write usage text.
        if (fileargs.length < 2) {
            Console.WriteLine(usageText);
        }
        else {
            try {
                // Create a random key using a random number generator.
 This 
                // would be the secret key shared by sender and receiver.
                ubyte secretKey[] = new ubyte[64];

                //RNGCryptoServiceProvider is an implementation of a
 random
                // number generator.
                RNGCryptoServiceProvider rng = new RNGCryptoServiceProvider();

                // The array is now filled with cryptographically strong
                // random bytes.
                rng.GetBytes(secretKey);

                // Use the secret key to encode the message file.
                EncodeFile(secretKey, fileargs[0], fileargs[1]);

                // Take the encoded file and decode
                DecodeFile(secretKey, fileargs[1]);
            }
            catch (IOException e) {
                Console.WriteLine("Error: File not found", e);
            }
        }//end if-else
    } //end main
} //end class HMACRIPEMD160Example

プラットフォーム

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

開発プラットフォームの中には、.NET Framework によってサポートされていないバージョンがあります。サポートされているバージョンについては、「システム要件」を参照してください。

バージョン情報

.NET Framework
サポート対象 : 2.0

参照

関連項目
HMACRIPEMD160 クラス
HMACRIPEMD160 メンバ
System.Security.Cryptography 名前空間
その他の技術情報
暗号サービス