HMACSHA384 HMACSHA384 HMACSHA384 HMACSHA384 Class

Definice

Pomocí ověřování kódu metoda HMAC (Message) Hash-based výpočetní prostředí SHA384 funkce hash.Computes a Hash-based Message Authentication Code (HMAC) using the SHA384 hash function.

public ref class HMACSHA384 : System::Security::Cryptography::HMAC
[System.Runtime.InteropServices.ComVisible(true)]
public class HMACSHA384 : System.Security.Cryptography.HMAC
type HMACSHA384 = class
    inherit HMAC
Public Class HMACSHA384
Inherits HMAC
Dědičnost
Atributy

Příklady

Následující příklad ukazuje, jak podepsat soubor pomocí HMACSHA384 objektu a postup pro ověření souboru.The following example shows how to sign a file by using the HMACSHA384 object, and then how to verify the file.

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.
   HMACSHA384^ myhmacsha384 = gcnew HMACSHA384( 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 = myhmacsha384->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 );

   myhmacsha384->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. 
   HMACSHA384^ hmacsha384 = gcnew HMACSHA384( key );
   
   // Create an array to hold the keyed hash value read from the file.
   array<Byte>^storedHash = gcnew array<Byte>(hmacsha384->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 = hmacsha384->ComputeHash( inStream );
   
   // compare the computed hash with the stored value
   bool err = false;
   for ( int i = 0; i < storedHash->Length; i++ )
   {
      if ( computedHash[ i ] != storedHash[ i ] )
      {
         err = true;
      }
   }
   if (err)
        {
            Console::WriteLine("Hash values differ! Encoded file has been tampered with!");
            return false;
        }
        else
        {
            Console::WriteLine("Hash values agree -- no tampering occurred.");
            return true;
        }

} //end DecodeFile


int main()
{
   array<String^>^Fileargs = Environment::GetCommandLineArgs();
   String^ usageText = "Usage: HMACSHA384 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


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

public class HMACSHA384example
{

    public static void Main(string[] Fileargs)
    {
        string dataFile;
        string signedFile;
        //If no file names are specified, create them.
        if (Fileargs.Length < 2)
        {
            dataFile = @"text.txt";
            signedFile = "signedFile.enc";

            if (!File.Exists(dataFile))
            {
                // Create a file to write to.
                using (StreamWriter sw = File.CreateText(dataFile))
                {
                    sw.WriteLine("Here is a message to sign");
                }
            }

        }
        else
        {
            dataFile = Fileargs[0];
            signedFile = Fileargs[1];
        }
        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.
            using (RNGCryptoServiceProvider rng = new RNGCryptoServiceProvider())
            {
                // The array is now filled with cryptographically strong random bytes.
                rng.GetBytes(secretkey);

                // Use the secret key to sign the message file.
                SignFile(secretkey, dataFile, signedFile);

                // Verify the signed file
                VerifyFile(secretkey, signedFile);
            }
        }
        catch (IOException e)
        {
            Console.WriteLine("Error: File not found", e);
        }

    }  //end main
    // Computes a keyed hash for a source file and creates a target file with the keyed hash
    // prepended to the contents of the source file. 
    public static void SignFile(byte[] key, String sourceFile, String destFile)
    {
        // Initialize the keyed hash object.
        using (HMACSHA384 hmac = new HMACSHA384(key))
        {
            using (FileStream inStream = new FileStream(sourceFile, FileMode.Open))
            {
                using (FileStream outStream = new FileStream(destFile, FileMode.Create))
                {
                    // Compute the hash of the input file.
                    byte[] hashValue = hmac.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);
                }
            }
        }
        return;
    } // end SignFile


    // Compares the key in the source file with a new key created for the data portion of the file. If the keys 
    // compare the data has not been tampered with.
    public static bool VerifyFile(byte[] key, String sourceFile)
    {
        bool err = false;
        // Initialize the keyed hash object. 
        using (HMACSHA384 hmac = new HMACSHA384(key))
        {
            // Create an array to hold the keyed hash value read from the file.
            byte[] storedHash = new byte[hmac.HashSize / 8];
            // Create a FileStream for the source file.
            using (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 = hmac.ComputeHash(inStream);
                // compare the computed hash with the stored value

                for (int i = 0; i < storedHash.Length; i++)
                {
                    if (computedHash[i] != storedHash[i])
                    {
                        err = true;
                    }
                }
            }
        }
        if (err)
        {
            Console.WriteLine("Hash values differ! Signed file has been tampered with!");
            return false;
        }
        else
        {
            Console.WriteLine("Hash values agree -- no tampering occurred.");
            return true;
        }

    } //end VerifyFile

} //end class
Imports System
Imports System.IO
Imports System.Security.Cryptography

Public Class HMACSHA384example

    Public Shared Sub Main(ByVal Fileargs() As String)
        Dim dataFile As String
        Dim signedFile As String
        'If no file names are specified, create them.
        If Fileargs.Length < 2 Then
            dataFile = "text.txt"
            signedFile = "signedFile.enc"

            If Not File.Exists(dataFile) Then
                ' Create a file to write to.
                Using sw As StreamWriter = File.CreateText(dataFile)
                    sw.WriteLine("Here is a message to sign")
                End Using
            End If

        Else
            dataFile = Fileargs(0)
            signedFile = Fileargs(1)
        End If
        Try
            ' Create a random key using a random number generator. This would be the
            '  secret key shared by sender and receiver.
            Dim secretkey() As Byte = New [Byte](63) {}
            'RNGCryptoServiceProvider is an implementation of a random number generator.
            Using rng As New RNGCryptoServiceProvider()
                ' The array is now filled with cryptographically strong random bytes.
                rng.GetBytes(secretkey)

                ' Use the secret key to encode the message file.
                SignFile(secretkey, dataFile, signedFile)

                ' Take the encoded file and decode
                VerifyFile(secretkey, signedFile)
            End Using
        Catch e As IOException
            Console.WriteLine("Error: File not found", e)
        End Try

    End Sub 'Main

    ' Computes a keyed hash for a source file and creates a target file with the keyed hash
    ' prepended to the contents of the source file. 
    Public Shared Sub SignFile(ByVal key() As Byte, ByVal sourceFile As String, ByVal destFile As String)
        ' Initialize the keyed hash object.
        Using myhmac As New HMACSHA384(key)
            Using inStream As New FileStream(sourceFile, FileMode.Open)
                Using outStream As New FileStream(destFile, FileMode.Create)
                    ' Compute the hash of the input file.
                    Dim hashValue As Byte() = myhmac.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.
                    Dim bytesRead As Integer
                    ' read 1K at a time
                    Dim buffer(1023) As Byte
                    Do
                        ' Read from the wrapping CryptoStream.
                        bytesRead = inStream.Read(buffer, 0, 1024)
                        outStream.Write(buffer, 0, bytesRead)
                    Loop While bytesRead > 0
                End Using
            End Using
        End Using
        Return

    End Sub 'SignFile
    ' end SignFile

    ' Compares the key in the source file with a new key created for the data portion of the file. If the keys 
    ' compare the data has not been tampered with.
    Public Shared Function VerifyFile(ByVal key() As Byte, ByVal sourceFile As String) As Boolean
        Dim err As Boolean = False
        ' Initialize the keyed hash object. 
        Using hmac As New HMACSHA384(key)
            ' Create an array to hold the keyed hash value read from the file.
            Dim storedHash(hmac.HashSize / 8) As Byte
            ' Create a FileStream for the source file.
            Using inStream As New FileStream(sourceFile, FileMode.Open)
                ' Read in the storedHash.
                inStream.Read(storedHash, 0, storedHash.Length - 1)
                ' 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.
                Dim computedHash As Byte() = hmac.ComputeHash(inStream)
                ' compare the computed hash with the stored value
                Dim i As Integer
                For i = 0 To storedHash.Length - 2
                    If computedHash(i) <> storedHash(i) Then
                        err = True
                    End If
                Next i
            End Using
        End Using
        If err Then
            Console.WriteLine("Hash values differ! Signed file has been tampered with!")
            Return False
        Else
            Console.WriteLine("Hash values agree -- no tampering occurred.")
            Return True
        End If

    End Function 'VerifyFile 
End Class 'HMACSHA384example 'end VerifyFile
'end class

Poznámky

HMACSHA384 je typ klíčovaný algoritmus hash, který je vytvořen z funkce hash SHA-384 a použít jako Hash-based kódu (metoda HMAC Message Authentication).HMACSHA384 is a type of keyed hash algorithm that is constructed from the SHA-384 hash function and used as a Hash-based Message Authentication Code (HMAC). Proces HMAC s daty zprávy zkombinuje tajný klíč a vytvoří.The HMAC process mixes a secret key with the message data and hashes the result. Hodnota hash je přimíchán tajný klíč znovu a pak mají hodnotu hash podruhé.The hash value is mixed with the secret key again, and then hashed a second time. Výchozí hodnota hash má 384 bitů.The output hash is 384 bits long.

Kódu HMAC s lze použít k určení, zda zpráva odeslaná přes nezabezpečený kanál bylo manipulováno, za předpokladu, že odesílatel a příjemce sdílet tajný klíč.An HMAC can be used to determine whether a message sent over a nonsecure channel has been tampered with, provided that the sender and receiver share a secret key. Odesílatel vypočítá hodnotu hash pro původní data a odešle na původní data a hodnota hash jako jedna zpráva.The sender computes the hash value for the original data and sends both the original data and the hash value as a single message. Příjemce přepočítá hodnoty hash na přijatou zprávu a zkontroluje, že odpovídá Vypočítaný algoritmus HMAC přenášená HMAC.The receiver recalculates the hash value on the received message and checks that the computed HMAC matches the transmitted HMAC.

Pokud se shodují se hodnoty hash původního a vypočítané, je zpráva ověřena.If the original and computed hash values match, the message is authenticated. Pokud shodné nejsou, data nebo hodnoty hash se změnil.If they do not match, either the data or the hash value has been changed. HMAC poskytují zabezpečení před manipulací vzhledem k tomu, že znalost tajného klíče je potřeba změnit zprávu a reprodukovat správným hashovacím hodnotu.HMACs provide security against tampering because knowledge of the secret key is required to change the message and reproduce the correct hash value.

HMACSHA384 přijímá všech velikostí klíče a vytvoří hodnotu hash sekvence, která je 384 bitů.HMACSHA384 accepts all key sizes and produces a hash sequence that is 384 bits long.

Konstruktory

HMACSHA384() HMACSHA384() HMACSHA384() HMACSHA384()

Inicializuje novou instanci třídy HMACSHA384 pomocí náhodně vygenerovaný klíč.Initializes a new instance of the HMACSHA384 class by using a randomly generated key.

HMACSHA384(Byte[]) HMACSHA384(Byte[]) HMACSHA384(Byte[]) HMACSHA384(Byte[])

Inicializuje novou instanci třídy HMACSHA384 pomocí zadaného klíče dat třídy.Initializes a new instance of the HMACSHA384 class by using the specified key data.

Vlastnosti

BlockSizeValue BlockSizeValue BlockSizeValue BlockSizeValue

Získá nebo nastaví velikost bloku pro použití v hodnotě hash.Gets or sets the block size to use in the hash value.

(Inherited from HMAC)
CanReuseTransform CanReuseTransform CanReuseTransform CanReuseTransform

Získá hodnotu označující, zda lze znovu použít aktuální transformace.Gets a value indicating whether the current transform can be reused.

(Inherited from HashAlgorithm)
CanTransformMultipleBlocks CanTransformMultipleBlocks CanTransformMultipleBlocks CanTransformMultipleBlocks

Při přepisu v odvozené třídě získá hodnotu, která udává, zda je možné transformovat více bloků.When overridden in a derived class, gets a value indicating whether multiple blocks can be transformed.

(Inherited from HashAlgorithm)
Hash Hash Hash Hash

Získá hodnotu kód Vypočítaný algoritmus hash.Gets the value of the computed hash code.

(Inherited from HashAlgorithm)
HashName HashName HashName HashName

Získá nebo nastaví název hashovacího algoritmu pro algoritmus hash.Gets or sets the name of the hash algorithm to use for hashing.

(Inherited from HMAC)
HashSize HashSize HashSize HashSize
InputBlockSize InputBlockSize InputBlockSize InputBlockSize

Při přepisu v odvozené třídě, získá velikost vstupní blok.When overridden in a derived class, gets the input block size.

(Inherited from HashAlgorithm)
Key Key Key Key
OutputBlockSize OutputBlockSize OutputBlockSize OutputBlockSize

Při přepisu v odvozené třídě, získá výstupní velikost bloku.When overridden in a derived class, gets the output block size.

(Inherited from HashAlgorithm)
ProduceLegacyHmacValues ProduceLegacyHmacValues ProduceLegacyHmacValues ProduceLegacyHmacValues

Poskytuje řešení pro .NET Framework 2.0.NET Framework 2.0 provádění HMACSHA384 algoritmus, který je konzistentní s .NET Framework 2.0 Service Pack 1.NET Framework 2.0 Service Pack 1 provádění algoritmu.Provides a workaround for the .NET Framework 2.0.NET Framework 2.0 implementation of the HMACSHA384 algorithm, which is inconsistent with the .NET Framework 2.0 Service Pack 1.NET Framework 2.0 Service Pack 1 implementation of the algorithm.

Metody

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

Uvolní všechny prostředky používané HashAlgorithm třídy.Releases all resources used by the HashAlgorithm class.

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

Vypočítá hodnotu hash pro zadané bajtové pole.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)

Vypočítá hodnotu hash pro zadané oblasti zadané bajtové pole.Computes the hash value for the specified region of the specified byte array.

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

Vypočítá hodnotu hash pro zadaná Stream objektu.Computes the hash value for the specified Stream object.

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

Uvolní všechny prostředky používané aktuální instancí třídy HashAlgorithm třídy.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)

Určuje, zda se zadaný objekt rovná aktuálnímu objektu.Determines whether the specified object is equal to the current object.

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

Slouží jako výchozí funkce hash.Serves as the default hash function.

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

Získá Type aktuální instance.Gets the Type of the current instance.

(Inherited from Object)
HashCore(Byte[], Int32, Int32) HashCore(Byte[], Int32, Int32) HashCore(Byte[], Int32, Int32) HashCore(Byte[], Int32, Int32)
HashCore(ReadOnlySpan<Byte>) HashCore(ReadOnlySpan<Byte>) HashCore(ReadOnlySpan<Byte>) HashCore(ReadOnlySpan<Byte>)
HashFinal() HashFinal() HashFinal() HashFinal()
Initialize() Initialize() Initialize() Initialize()
MemberwiseClone() MemberwiseClone() MemberwiseClone() MemberwiseClone()

Vytvoří Mělkou kopii aktuální Object.Creates a shallow copy of the current Object.

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

Vrací řetězec, který představuje aktuální objekt.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)

Vypočítá hodnotu hash pro zadané oblasti vstupního bajtového pole a zkopíruje do zadané oblasti výstupního bajtového pole zadané oblasti vstupního bajtového pole.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)

Vypočítá hodnotu hash pro zadané oblasti zadané bajtové pole.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)

Pole

HashSizeValue HashSizeValue HashSizeValue HashSizeValue

Představuje velikost v bitech, vypočtená hodnota hash.Represents the size, in bits, of the computed hash code.

(Inherited from HashAlgorithm)
HashValue HashValue HashValue HashValue

Představuje hodnotu kód Vypočítaný algoritmus hash.Represents the value of the computed hash code.

(Inherited from HashAlgorithm)
KeyValue KeyValue KeyValue KeyValue

Klíč pro použití v algoritmu hash.The key to use in the hash algorithm.

(Inherited from KeyedHashAlgorithm)
State State State State

Představuje stav výpočet hodnoty hash.Represents the state of the hash computation.

(Inherited from HashAlgorithm)

Explicitní implementace rozhraní

IDisposable.Dispose() IDisposable.Dispose() IDisposable.Dispose() IDisposable.Dispose()

Uvolní nespravované prostředky využívané třídou HashAlgorithm a volitelně také spravované prostředky.Releases the unmanaged resources used by the HashAlgorithm and optionally releases the managed resources.

(Inherited from HashAlgorithm)

Platí pro

Viz také