HashAlgorithm.ComputeHash Méthode

Référence

Définition

Espace de noms:: System.Security.Cryptography

Assembly:: System.Security.Cryptography.Primitives.dll

Assembly:: netstandard.dll

Assembly:: mscorlib.dll

Important

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Calcule la valeur de hachage pour les données d'entrée.

Surcharges

ComputeHash(Byte[])	Calcule la valeur de hachage pour le tableau d'octets spécifié.
ComputeHash(Stream)	Calcule la valeur de hachage pour l'objet Stream spécifié.
ComputeHash(Byte[], Int32, Int32)	Calcule la valeur de hachage pour la région spécifiée du tableau d'octets spécifié.

ComputeHash(Byte[])

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

public:
 cli::array <System::Byte> ^ ComputeHash(cli::array <System::Byte> ^ buffer);

public byte[] ComputeHash (byte[] buffer);

member this.ComputeHash : byte[] -> byte[]

Public Function ComputeHash (buffer As Byte()) As Byte()

Paramètres

buffer: Byte[]

Entrée pour laquelle le code de hachage doit être calculé.

Retours

Byte[]

Code de hachage calculé.

Exceptions

ArgumentNullException

buffer est null.

ObjectDisposedException

L'objet a déjà été supprimé.

Exemples

L’exemple suivant calcule la SHA256 valeur de hachage d’une chaîne et retourne le hachage sous la forme d’une chaîne de 64 caractères au format hexadécimal. La chaîne de hachage créée par cet exemple de code est compatible avec toute fonction de hachage SHA256 (sur n’importe quelle plateforme) qui crée une chaîne de hachage au format hexadécimal de 64 caractères.

using System;
using System.Security.Cryptography;
using System.Text;

public class Program
{
    public static void Main()
    {
        string source = "Hello World!";
        using (SHA256 sha256Hash = SHA256.Create())
        {
            string hash = GetHash(sha256Hash, source);

            Console.WriteLine($"The SHA256 hash of {source} is: {hash}.");

            Console.WriteLine("Verifying the hash...");

            if (VerifyHash(sha256Hash, source, hash))
            {
                Console.WriteLine("The hashes are the same.");
            }
            else
            {
                Console.WriteLine("The hashes are not same.");
            }
        }
    }

    private static string GetHash(HashAlgorithm hashAlgorithm, string input)
    {

        // Convert the input string to a byte array and compute the hash.
        byte[] data = hashAlgorithm.ComputeHash(Encoding.UTF8.GetBytes(input));

        // Create a new Stringbuilder to collect the bytes
        // and create a string.
        var sBuilder = new StringBuilder();

        // Loop through each byte of the hashed data
        // and format each one as a hexadecimal string.
        for (int i = 0; i < data.Length; i++)
        {
            sBuilder.Append(data[i].ToString("x2"));
        }

        // Return the hexadecimal string.
        return sBuilder.ToString();
    }

    // Verify a hash against a string.
    private static bool VerifyHash(HashAlgorithm hashAlgorithm, string input, string hash)
    {
        // Hash the input.
        var hashOfInput = GetHash(hashAlgorithm, input);

        // Create a StringComparer an compare the hashes.
        StringComparer comparer = StringComparer.OrdinalIgnoreCase;

        return comparer.Compare(hashOfInput, hash) == 0;
    }
}
// The example displays the following output:
//    The SHA256 hash of Hello World! is: 7f83b1657ff1fc53b92dc18148a1d65dfc2d4b1fa3d677284addd200126d9069.
//    Verifying the hash...
//    The hashes are the same.

Imports System.Security.Cryptography
Imports System.Text

Public Module Program
    Public Sub Main()
        Dim source As String = "Hello World!"
        Using sha256Hash As SHA256 = SHA256.Create()

            Dim hash As String = GetHash(sha256Hash, source)

            Console.WriteLine($"The SHA256 hash of {source} is: {hash}.")

            Console.WriteLine("Verifying the hash...")

            If VerifyHash(sha256Hash, source, hash) Then
                Console.WriteLine("The hashes are the same.")
            Else
                Console.WriteLine("The hashes are not same.")
            End If
        End Using
    End Sub 

    Private Function GetHash(ByVal hashAlgorithm As HashAlgorithm, ByVal input As String) As String

        ' Convert the input string to a byte array and compute the hash.
        Dim data As Byte() = hashAlgorithm.ComputeHash(Encoding.UTF8.GetBytes(input))

        ' Create a new Stringbuilder to collect the bytes
        ' and create a string.
        Dim sBuilder As New StringBuilder()

        ' Loop through each byte of the hashed data 
        ' and format each one as a hexadecimal string.
        For i As Integer = 0 To data.Length - 1
            sBuilder.Append(data(i).ToString("x2"))
        Next

        ' Return the hexadecimal string.
        Return sBuilder.ToString()
    End Function

    ' Verify a hash against a string.
    Private Function VerifyHash(hashAlgorithm As HashAlgorithm, input As String, hash As String) As Boolean
        ' Hash the input.
        Dim hashOfInput As String = GetHash(hashAlgorithm, input)

        ' Create a StringComparer an compare the hashes.
        Dim comparer As StringComparer = StringComparer.OrdinalIgnoreCase

        Return comparer.Compare(hashOfInput, hash) = 0
    End Function
End Module
' The example displays the following output:
'    The SHA256 hash of Hello World! is: 7f83b1657ff1fc53b92dc18148a1d65dfc2d4b1fa3d677284addd200126d9069.
'    Verifying the hash...
'    The hashes are the same.

S’applique à

ComputeHash(Stream)

Calcule la valeur de hachage pour l'objet Stream spécifié.

public:
 cli::array <System::Byte> ^ ComputeHash(System::IO::Stream ^ inputStream);

public byte[] ComputeHash (System.IO.Stream inputStream);

member this.ComputeHash : System.IO.Stream -> byte[]

Public Function ComputeHash (inputStream As Stream) As Byte()

Paramètres

inputStream: Stream

Entrée pour laquelle le code de hachage doit être calculé.

Retours

Byte[]

Code de hachage calculé.

Exceptions

ObjectDisposedException

L'objet a déjà été supprimé.

Exemples

L’exemple suivant calcule le SHA256 hachage de tous les fichiers d’un répertoire.

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

public class HashDirectory
{
    public static void Main(string[] args)
    {
        if (args.Length < 1)
        {
            Console.WriteLine("No directory selected.");
            return;
        }

        string directory = args[0];
        if (Directory.Exists(directory))
        {
            // Create a DirectoryInfo object representing the specified directory.
            var dir = new DirectoryInfo(directory);
            // Get the FileInfo objects for every file in the directory.
            FileInfo[] files = dir.GetFiles();
            // Initialize a SHA256 hash object.
            using (SHA256 mySHA256 = SHA256.Create())
            {
                // Compute and print the hash values for each file in directory.
                foreach (FileInfo fInfo in files)
                {
                    using (FileStream fileStream = fInfo.Open(FileMode.Open))
                    {
                        try
                        {
                            // Create a fileStream for the file.
                            // Be sure it's positioned to the beginning of the stream.
                            fileStream.Position = 0;
                            // Compute the hash of the fileStream.
                            byte[] hashValue = mySHA256.ComputeHash(fileStream);
                            // Write the name and hash value of the file to the console.
                            Console.Write($"{fInfo.Name}: ");
                            PrintByteArray(hashValue);
                        }
                        catch (IOException e)
                        {
                            Console.WriteLine($"I/O Exception: {e.Message}");
                        }
                        catch (UnauthorizedAccessException e)
                        {
                            Console.WriteLine($"Access Exception: {e.Message}");
                        }
                    }
                }
            }
        }
        else
        {
            Console.WriteLine("The directory specified could not be found.");
        }
    }

    // Display the byte array in a readable format.
    public static void PrintByteArray(byte[] array)
    {
        for (int i = 0; i < array.Length; i++)
        {
            Console.Write($"{array[i]:X2}");
            if ((i % 4) == 3) Console.Write(" ");
        }
        Console.WriteLine();
    }
}

Imports System.IO
Imports System.Security.Cryptography

Public Module HashDirectory

    Public Sub Main(ByVal args() As String)
        If args.Length < 1 Then
            Console.WriteLine("No directory selected")
            Return
        End If

        Dim targetDirectory As String = args(0)
        If Directory.Exists(targetDirectory) Then
            ' Create a DirectoryInfo object representing the specified directory.
            Dim dir As New DirectoryInfo(targetDirectory)
            ' Get the FileInfo objects for every file in the directory.
            Dim files As FileInfo() = dir.GetFiles()
            ' Initialize a SHA256 hash object.
            Using mySHA256 As SHA256 = SHA256.Create()
                ' Compute and print the hash values for each file in directory.
                For Each fInfo  As FileInfo In files
                    Try
                        ' Create a fileStream for the file.
                        Dim 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.
                        Dim hashValue() As Byte = 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()
                    Catch e As IOException
                        Console.WriteLine($"I/O Exception: {e.Message}")
                    Catch e As UnauthorizedAccessException 
                        Console.WriteLine($"Access Exception: {e.Message}")
                    End Try    
                Next 
            End Using
        Else
           Console.WriteLine("The directory specified could not be found.")
        End If
    End Sub

    ' Print the byte array in a readable format.
    Public Sub PrintByteArray(array() As Byte)
        For i As Integer = 0 To array.Length - 1
            Console.Write($"{array(i):X2}")
            If i Mod 4 = 3 Then
                Console.Write(" ")
            End If
        Next 
        Console.WriteLine()

    End Sub 
End Module

S’applique à

ComputeHash(Byte[], Int32, Int32)

Calcule la valeur de hachage pour la région spécifiée du tableau d'octets spécifié.

public:
 cli::array <System::Byte> ^ ComputeHash(cli::array <System::Byte> ^ buffer, int offset, int count);

public byte[] ComputeHash (byte[] buffer, int offset, int count);

member this.ComputeHash : byte[] * int * int -> byte[]

Public Function ComputeHash (buffer As Byte(), offset As Integer, count As Integer) As Byte()

Paramètres

buffer: Byte[]

Entrée pour laquelle le code de hachage doit être calculé.

offset: Int32

Offset dans le tableau d'octets à partir duquel l'utilisation de données commence.

count: Int32

Nombre d'octets dans le tableau à utiliser comme données.

Retours

Byte[]

Code de hachage calculé.

Exceptions

ArgumentException

count n’est pas une valeur valide.

ou -

buffer a une longueur non valide.

ArgumentNullException

buffer est null.

ArgumentOutOfRangeException

offset est hors limites. Ce paramètre requiert un nombre non négatif.

ObjectDisposedException

L'objet a déjà été supprimé.

S’applique à

HashAlgorithm.ComputeHash Méthode

Définition

Surcharges

ComputeHash(Byte[])

Paramètres

Retours

Exceptions

Exemples

S’applique à

ComputeHash(Stream)

Paramètres

Retours

Exceptions

Exemples

S’applique à

ComputeHash(Byte[], Int32, Int32)

Paramètres

Retours

Exceptions

S’applique à

Ressources supplémentaires