HMACSHA1 HMACSHA1 HMACSHA1 HMACSHA1 Class

Определение

Вычисляет хэш-код проверки подлинности сообщения (HMAC) с помощью хэш-функции SHA1.Computes a Hash-based Message Authentication Code (HMAC) using the SHA1 hash function.

public ref class HMACSHA1 : System::Security::Cryptography::HMAC
[System.Runtime.InteropServices.ComVisible(true)]
public class HMACSHA1 : System.Security.Cryptography.HMAC
type HMACSHA1 = class
    inherit HMAC
Public Class HMACSHA1
Inherits HMAC
Наследование
Атрибуты

Примеры

В следующем примере кода показано, как подписать файл с помощью HMACSHA1 объект и затем проверить файл.The following code example shows how to sign a file by using the HMACSHA1 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.
   HMACSHA1^ myhmacsha1 = gcnew HMACSHA1( 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 = myhmacsha1->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 );

   myhmacsha1->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. 
   HMACSHA1^ hmacsha1 = gcnew HMACSHA1( key );
   
   // Create an array to hold the keyed hash value read from the file.
   array<Byte>^storedHash = gcnew array<Byte>(hmacsha1->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 = hmacsha1->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: HMACSHA1 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 HMACSHA1example
{

    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 (HMACSHA1 hmac = new HMACSHA1(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 (HMACSHA1 hmac = new HMACSHA1(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 HMACSHA1example

    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 HMACSHA1(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 HMACSHA1(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 'HMACSHA1example 'end VerifyFile
'end class

Комментарии

HMACSHA1 — это разновидность хэш-алгоритма, который создан на основе хэш-функции SHA1 и используется как код проверки подлинности сообщения на основе хэша или HMAC.HMACSHA1 is a type of keyed hash algorithm that is constructed from the SHA1 hash function and used as an HMAC, or hash-based message authentication code. Процесс HMAC смешивании секретного ключа с данными сообщения, хэширует результат хэш-функции, еще раз смешивании хэш-значения с секретным ключом и затем применяет хэш-функцию еще раз.The HMAC process mixes a secret key with the message data, hashes the result with the hash function, mixes that hash value with the secret key again, and then applies the hash function a second time. Выходные данные хэш-код является длиной 160 бит.The output hash is 160 bits in length.

Код HMAC можно использовать для определения факта подделки сообщения, передаваемого по незащищенному каналу, при условии, что отправитель и получатель общий секретный ключ.An HMAC 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. Отправитель вычисляет хэш-значение для исходных данных и отправляет хэш-значения и исходные данные в одном сообщении.The sender computes the hash value for the original data and sends both the original data and hash value as a single message. Получатель повторно вычисляет хэш-значение для полученного сообщения и проверяет, что совпадает передаваемых HMAC.The receiver recalculates the hash value on the received message and checks that the computed HMAC matches the transmitted HMAC.

Любое изменение данных или хэш-значения вызовет несовпадение, поскольку требуется знание секретного ключа, чтобы изменить сообщение и воспроизвести правильное значение хэша.Any change to the data or the hash value results in a mismatch, because knowledge of the secret key is required to change the message and reproduce the correct hash value. Таким образом Если исходные и вычисляемого хэш-значения совпадают, сообщение проходит проверку подлинности.Therefore, if the original and computed hash values match, the message is authenticated.

SHA-1 (Secure Hash Algorithm, также называется SHS, Secure Hash стандартный) — это криптографический хэш-алгоритм, опубликованное правительством США.The SHA-1 (Secure Hash Algorithm, also called SHS, Secure Hash Standard) is a cryptographic hash algorithm published by the United States Government. Он выдает значение 160-разрядного хэша из произвольной длины строки.It produces a 160-bit hash value from an arbitrary length string.

HMACSHA1 принимает ключи любого размера и создает хеш-последовательность, длиной 160 бит.HMACSHA1 accepts keys of any size, and produces a hash sequence that is 160 bits in length.

Конструкторы

HMACSHA1() HMACSHA1() HMACSHA1() HMACSHA1()

Инициализирует новый экземпляр класса HMACSHA1 созданным случайным образом ключом.Initializes a new instance of the HMACSHA1 class with a randomly generated key.

HMACSHA1(Byte[]) HMACSHA1(Byte[]) HMACSHA1(Byte[]) HMACSHA1(Byte[])

Инициализирует новый экземпляр класса HMACSHA1 указанными данными ключа.Initializes a new instance of the HMACSHA1 class with the specified key data.

HMACSHA1(Byte[], Boolean) HMACSHA1(Byte[], Boolean) HMACSHA1(Byte[], Boolean) HMACSHA1(Byte[], Boolean)

Инициализирует новый экземпляр класса HMACSHA1 с указанными данными ключа и значением, определяющим необходимость использования управляемой версии алгоритма SHA1.Initializes a new instance of the HMACSHA1 class with the specified key data and a value that specifies whether to use the managed version of the SHA1 algorithm.

Свойства

CanReuseTransform CanReuseTransform CanReuseTransform CanReuseTransform

Возвращает значение, указывающее, возможно ли повторное использование текущего преобразования.Gets a value indicating whether the current transform can be reused.

(Inherited from HashAlgorithm)
CanTransformMultipleBlocks CanTransformMultipleBlocks CanTransformMultipleBlocks CanTransformMultipleBlocks

Если переопределено в производном классе, возвращает значение, указывающее, возможно ли преобразование нескольких блоков.When overridden in a derived class, gets a value indicating whether multiple blocks can be transformed.

(Inherited from HashAlgorithm)
Hash Hash Hash Hash

Возвращает значение вычисляемого хэш-кода.Gets the value of the computed hash code.

(Inherited from HashAlgorithm)
HashName HashName HashName HashName
HashSize HashSize HashSize HashSize
InputBlockSize InputBlockSize InputBlockSize InputBlockSize

Если переопределено в производном классе, возвращает размер входного блока.When overridden in a derived class, gets the input block size.

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

Если переопределено в производном классе, возвращает размер выходного блока.When overridden in a derived class, gets the output block size.

(Inherited from HashAlgorithm)

Методы

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

Освобождает все ресурсы, используемые классом HashAlgorithm.Releases all resources used by the HashAlgorithm class.

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

Вычисляет хэш-значение для заданного массива байтов.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)

Вычисляет хэш-значение для заданной области заданного массива байтов.Computes the hash value for the specified region of the specified byte array.

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

Вычисляет хэш-значение для заданного объекта Stream.Computes the hash value for the specified Stream object.

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

Освобождает все ресурсы, используемые текущим экземпляром класса HashAlgorithm.Releases all resources used by the current instance of the HashAlgorithm class.

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

Этот член переопределяет Dispose(Boolean); по данной теме может быть доступна более полная документация.This member overrides Dispose(Boolean), and more complete documentation might be available in that topic.

Освобождает неуправляемые ресурсы, используемые объектом KeyedHashAlgorithm, а при необходимости освобождает также управляемые ресурсы.Releases the unmanaged resources used by the KeyedHashAlgorithm and optionally releases the managed resources.

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

Определяет, равен ли заданный объект текущему объекту.Determines whether the specified object is equal to the current object.

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

Служит хэш-функцией по умолчанию.Serves as the default hash function.

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

Возвращает объект Type для текущего экземпляра.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)

Передает данные, записанные в объект, в хэш-алгоритм SHA1 для вычисления кода проверки подлинности сообщения на основе хэш HMAC.Routes data written to the object into the SHA1 hash algorithm for computing the Hash-based Message Authentication Code (HMAC).

HashCore(ReadOnlySpan<Byte>) HashCore(ReadOnlySpan<Byte>) HashCore(ReadOnlySpan<Byte>) HashCore(ReadOnlySpan<Byte>)
HashFinal() HashFinal() HashFinal() HashFinal()
Initialize() Initialize() Initialize() Initialize()
MemberwiseClone() MemberwiseClone() MemberwiseClone() MemberwiseClone()

Создает неполную копию текущего объекта Object.Creates a shallow copy of the current Object.

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

Возвращает строку, представляющую текущий объект.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)

Вычисляет хэш-значение для заданной области входного массива байтов и копирует указанную область входного массива байтов в заданную область выходного массива байтов.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)

Вычисляет хэш-значение для заданной области заданного массива байтов.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)

Поля

HashSizeValue HashSizeValue HashSizeValue HashSizeValue

Представляет размер вычисляемого хэш-кода в битах.Represents the size, in bits, of the computed hash code.

(Inherited from HashAlgorithm)
HashValue HashValue HashValue HashValue

Представляет значение вычисляемого хэш-кода.Represents the value of the computed hash code.

(Inherited from HashAlgorithm)
KeyValue KeyValue KeyValue KeyValue

Ключ, используемый в хэш-алгоритме.The key to use in the hash algorithm.

(Inherited from KeyedHashAlgorithm)
State State State State

Представляет состояние процесса вычисления хэша.Represents the state of the hash computation.

(Inherited from HashAlgorithm)

Явные реализации интерфейса

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

Освобождает неуправляемые ресурсы, используемые объектом HashAlgorithm, а при необходимости освобождает также управляемые ресурсы.Releases the unmanaged resources used by the HashAlgorithm and optionally releases the managed resources.

(Inherited from HashAlgorithm)

Применяется к

Дополнительно