MACTripleDES MACTripleDES MACTripleDES MACTripleDES Class

Définition

Calcule un code MAC (Message Authentication Code) à l'aide de TripleDES pour les données d'entrée CryptoStream.Computes a Message Authentication Code (MAC) using TripleDES for the input data CryptoStream.

public ref class MACTripleDES : System::Security::Cryptography::KeyedHashAlgorithm
[System.Runtime.InteropServices.ComVisible(true)]
public class MACTripleDES : System.Security.Cryptography.KeyedHashAlgorithm
type MACTripleDES = class
    inherit KeyedHashAlgorithm
Public Class MACTripleDES
Inherits KeyedHashAlgorithm
Héritage
Attributs

Exemples

L’exemple suivant crée un Mac pour un fichier nommé input.txt, qui se trouve dans le dossier qui contient l’exemple d’exécutable.The following example creates a MAC for a file named input.txt, which is located in the folder that contains the example executable. Le Mac et le texte d’origine sont écrits dans un fichier encrypted.hsh nommé dans le même dossier.The MAC and the original text are written to a file named encrypted.hsh in the same folder. Le fichier signé est alors lu et le MAC est calculé pour la partie texte du fichier et comparé au MAC inclus avec le texte.The signed file is then read, and the MAC is calculated for the text portion of the file and compared to the MAC that is included with the text.

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

public class MACTripleDESexample
{

    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[24];
            //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 (MACTripleDES hmac = new MACTripleDES(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 (MACTripleDES hmac = new MACTripleDES(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.IO
Imports System.Security.Cryptography

Public Class MACTripleDESexample

    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](23) {}
            '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

    ' 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 MACTripleDES(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
    ' 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 MACTripleDES(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 'MACTripleDESexample 'end VerifyFile
'end class

Remarques

Un MAC peut être utilisé pour déterminer si un message envoyé sur un canal non sécurisé a été falsifié, à condition que l’expéditeur et le destinataire partagent une clé secrète.A MAC can be used to determine whether a message sent over an insecure channel has been tampered with, provided that the sender and receiver share a secret key. L’expéditeur calcule le MAC pour les données d’origine et les envoie sous forme de message unique.The sender computes the MAC for the original data, and sends both as a single message. Le destinataire recalcule le MAC sur le message reçu et vérifie que le MAC calculé correspond au MAC transmis.The receiver recomputes the MAC on the received message, and checks that the computed MAC matches the transmitted MAC.

Toute modification apportée aux données ou au MAC entraîne une incompatibilité, car la connaissance de la clé secrète est requise pour modifier le message et reproduire le bon MAC.Any change to the data or the MAC results in a mismatch, because knowledge of the secret key is required to change the message and reproduce the correct MAC. Par conséquent, si les codes correspondent, le message est authentifié.Therefore, if the codes match, the message is authenticated.

MACTripleDESutilise une clé d’une longueur de 16 ou 24 octets, et produit une séquence de hachage d’une longueur de 8 octets.MACTripleDES uses a key that is 16 or 24 bytes long, and produces a hash sequence that is 8 bytes long.

Constructeurs

MACTripleDES() MACTripleDES() MACTripleDES() MACTripleDES()

Initialise une nouvelle instance de la classe MACTripleDES.Initializes a new instance of the MACTripleDES class.

MACTripleDES(Byte[]) MACTripleDES(Byte[]) MACTripleDES(Byte[]) MACTripleDES(Byte[])

Initialise une nouvelle instance de la classe MACTripleDES avec les données de clé spécifiées.Initializes a new instance of the MACTripleDES class with the specified key data.

MACTripleDES(String, Byte[]) MACTripleDES(String, Byte[]) MACTripleDES(String, Byte[]) MACTripleDES(String, Byte[])

Initialise une nouvelle instance de la classe MACTripleDES avec les données de clé spécifiées à l'aide de l'implémentation spécifiée de TripleDES.Initializes a new instance of the MACTripleDES class with the specified key data and using the specified implementation of TripleDES.

Propriétés

CanReuseTransform CanReuseTransform CanReuseTransform CanReuseTransform

Obtient une valeur indiquant si la transformation actuelle peut être réutilisée.Gets a value indicating whether the current transform can be reused.

(Inherited from HashAlgorithm)
CanTransformMultipleBlocks CanTransformMultipleBlocks CanTransformMultipleBlocks CanTransformMultipleBlocks

En cas de substitution dans une classe dérivée, obtient une valeur indiquant si plusieurs blocs peuvent être transformés.When overridden in a derived class, gets a value indicating whether multiple blocks can be transformed.

(Inherited from HashAlgorithm)
Hash Hash Hash Hash

Obtient la valeur du code de hachage calculé.Gets the value of the computed hash code.

(Inherited from HashAlgorithm)
HashSize HashSize HashSize HashSize

Obtient la taille, en bits, du code de hachage calculé.Gets the size, in bits, of the computed hash code.

(Inherited from HashAlgorithm)
InputBlockSize InputBlockSize InputBlockSize InputBlockSize

En cas de substitution dans une classe dérivée, obtient la taille du bloc d'entrée.When overridden in a derived class, gets the input block size.

(Inherited from HashAlgorithm)
Key Key Key Key

Obtient ou définit la clé à utiliser dans l'algorithme de hachage.Gets or sets the key to use in the hash algorithm.

(Inherited from KeyedHashAlgorithm)
OutputBlockSize OutputBlockSize OutputBlockSize OutputBlockSize

En cas de substitution dans une classe dérivée, obtient la taille du bloc de sortie.When overridden in a derived class, gets the output block size.

(Inherited from HashAlgorithm)
Padding Padding Padding Padding

Obtient ou définit le mode de remplissage utilisé dans l'algorithme de hachage.Gets or sets the padding mode used in the hashing algorithm.

Méthodes

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

Libère toutes les ressources utilisées par la classe HashAlgorithm.Releases all resources used by the HashAlgorithm class.

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

Calcule la valeur de hachage pour le tableau d'octets spécifié.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)

Calcule la valeur de hachage pour la région spécifiée du tableau d'octets spécifié.Computes the hash value for the specified region of the specified byte array.

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

Calcule la valeur de hachage pour l'objet Stream spécifié.Computes the hash value for the specified Stream object.

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

Libère toutes les ressources utilisées par l'instance actuelle de la classe HashAlgorithm.Releases all resources used by the current instance of the HashAlgorithm class.

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

Libère les ressources utilisées par l'instance de MACTripleDES.Releases the resources used by the MACTripleDES instance.

Equals(Object) Equals(Object) Equals(Object) Equals(Object)

Détermine si l'objet spécifié est identique à l'objet actuel.Determines whether the specified object is equal to the current object.

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

Libère les ressources non managées utilisées par MACTripleDES.Releases the unmanaged resources used by the MACTripleDES.

GetHashCode() GetHashCode() GetHashCode() GetHashCode()

Fait office de fonction de hachage par défaut.Serves as the default hash function.

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

Obtient le Type de l'instance actuelle.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)

Achemine les données écrites dans l'objet vers le chiffreur TripleDES pour le calcul du code MAC (Message Authentication Code).Routes data written to the object into the TripleDES encryptor for computing the Message Authentication Code (MAC).

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

Retourne le code MAC (Message Authentication Code) calculé une fois les données écrites dans l'objet.Returns the computed Message Authentication Code (MAC) after all data is written to the object.

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

Initialise une instance de MACTripleDES.Initializes an instance of MACTripleDES.

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

Crée une copie superficielle de l'objet Object actuel.Creates a shallow copy of the current Object.

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

Retourne une chaîne qui représente l'objet actuel.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)

Calcule la valeur de hachage pour la région spécifiée du tableau d'octets d'entrée et copie la région spécifiée du tableau d'octets d'entrée dans la région spécifiée du tableau d'octets de sortie.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)

Calcule la valeur de hachage pour la région spécifiée du tableau d'octets spécifié.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) Inherited from HashAlgorithm

Champs

HashSizeValue HashSizeValue HashSizeValue HashSizeValue

Représente la taille, en bits, du code de hachage calculé.Represents the size, in bits, of the computed hash code.

(Inherited from HashAlgorithm)
HashValue HashValue HashValue HashValue

Représente la valeur du code de hachage calculé.Represents the value of the computed hash code.

(Inherited from HashAlgorithm)
KeyValue KeyValue KeyValue KeyValue

Clé à utiliser dans l'algorithme de hachage.The key to use in the hash algorithm.

(Inherited from KeyedHashAlgorithm)
State State State State

Représente l'état du calcul du hachage.Represents the state of the hash computation.

(Inherited from HashAlgorithm)

Implémentations d’interfaces explicites

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

Libère les ressources non managées utilisées par HashAlgorithm et libère éventuellement les ressources managées.Releases the unmanaged resources used by the HashAlgorithm and optionally releases the managed resources.

(Inherited from HashAlgorithm)

S’applique à