Rfc2898DeriveBytes Rfc2898DeriveBytes Rfc2898DeriveBytes Rfc2898DeriveBytes Constructors

Definition

Overloads

Rfc2898DeriveBytes(String, Byte[]) Rfc2898DeriveBytes(String, Byte[]) Rfc2898DeriveBytes(String, Byte[]) Rfc2898DeriveBytes(String, Byte[])

Initializes a new instance of the Rfc2898DeriveBytes class using a password and salt to derive the key.

Rfc2898DeriveBytes(String, Int32) Rfc2898DeriveBytes(String, Int32) Rfc2898DeriveBytes(String, Int32) Rfc2898DeriveBytes(String, Int32)

Initializes a new instance of the Rfc2898DeriveBytes class using the password and salt size to derive the key.

Rfc2898DeriveBytes(Byte[], Byte[], Int32) Rfc2898DeriveBytes(Byte[], Byte[], Int32) Rfc2898DeriveBytes(Byte[], Byte[], Int32) Rfc2898DeriveBytes(Byte[], Byte[], Int32)

Initializes a new instance of the Rfc2898DeriveBytes class using a password, a salt, and number of iterations to derive the key.

Rfc2898DeriveBytes(String, Byte[], Int32) Rfc2898DeriveBytes(String, Byte[], Int32) Rfc2898DeriveBytes(String, Byte[], Int32) Rfc2898DeriveBytes(String, Byte[], Int32)

Initializes a new instance of the Rfc2898DeriveBytes class using a password, a salt, and number of iterations to derive the key.

Rfc2898DeriveBytes(String, Int32, Int32) Rfc2898DeriveBytes(String, Int32, Int32) Rfc2898DeriveBytes(String, Int32, Int32) Rfc2898DeriveBytes(String, Int32, Int32)

Initializes a new instance of the Rfc2898DeriveBytes class using a password, a salt size, and number of iterations to derive the key.

Rfc2898DeriveBytes(Byte[], Byte[], Int32, HashAlgorithmName) Rfc2898DeriveBytes(Byte[], Byte[], Int32, HashAlgorithmName) Rfc2898DeriveBytes(Byte[], Byte[], Int32, HashAlgorithmName) Rfc2898DeriveBytes(Byte[], Byte[], Int32, HashAlgorithmName)

Initializes a new instance of the Rfc2898DeriveBytes class using the specified password, salt, number of iterations and the hash algorithm name to derive the key.

Rfc2898DeriveBytes(String, Byte[], Int32, HashAlgorithmName) Rfc2898DeriveBytes(String, Byte[], Int32, HashAlgorithmName) Rfc2898DeriveBytes(String, Byte[], Int32, HashAlgorithmName) Rfc2898DeriveBytes(String, Byte[], Int32, HashAlgorithmName)

Initializes a new instance of the Rfc2898DeriveBytes class using the specified password, salt, number of iterations and the hash algorithm name to derive the key.

Rfc2898DeriveBytes(String, Int32, Int32, HashAlgorithmName) Rfc2898DeriveBytes(String, Int32, Int32, HashAlgorithmName) Rfc2898DeriveBytes(String, Int32, Int32, HashAlgorithmName) Rfc2898DeriveBytes(String, Int32, Int32, HashAlgorithmName)

Initializes a new instance of the Rfc2898DeriveBytes class using the specified password, salt size, number of iterations and the hash algorithm name to derive the key.

Rfc2898DeriveBytes(String, Byte[]) Rfc2898DeriveBytes(String, Byte[]) Rfc2898DeriveBytes(String, Byte[]) Rfc2898DeriveBytes(String, Byte[])

Initializes a new instance of the Rfc2898DeriveBytes class using a password and salt to derive the key.

public:
 Rfc2898DeriveBytes(System::String ^ password, cli::array <System::Byte> ^ salt);
public Rfc2898DeriveBytes (string password, byte[] salt);
new System.Security.Cryptography.Rfc2898DeriveBytes : string * byte[] -> System.Security.Cryptography.Rfc2898DeriveBytes
Public Sub New (password As String, salt As Byte())

Parameters

password
String String String String

The password used to derive the key.

salt
Byte[]

The key salt used to derive the key.

Exceptions

The specified salt size is smaller than 8 bytes or the iteration count is less than 1.

Examples

The following code example uses the Rfc2898DeriveBytes class to create two identical keys for the TripleDES class. It then encrypts and decrypts some data using the keys.

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

// Generate a key k1 with password pwd1 and salt salt1.
// Generate a key k2 with password pwd1 and salt salt1.
// Encrypt data1 with key k1 using symmetric encryption, creating edata1.
// Decrypt edata1 with key k2 using symmetric decryption, creating data2.
// data2 should equal data1.

int main()
{
   array<String^>^passwordargs = Environment::GetCommandLineArgs();
   String^ usageText = "Usage: RFC2898 <password>\nYou must specify the password for encryption.\n";

   //If no file name is specified, write usage text.
   if ( passwordargs->Length == 1 )
   {
      Console::WriteLine( usageText );
   }
   else
   {
      String^ pwd1 = passwordargs[ 1 ];
      
      array<Byte>^salt1 = gcnew array<Byte>(8);
	  RNGCryptoServiceProvider ^ rngCsp = gcnew RNGCryptoServiceProvider();
		 rngCsp->GetBytes(salt1);
      //data1 can be a string or contents of a file.
      String^ data1 = "Some test data";

      //The default iteration count is 1000 so the two methods use the same iteration count.
      int myIterations = 1000;

      try
      {
         Rfc2898DeriveBytes ^ k1 = gcnew Rfc2898DeriveBytes( pwd1,salt1,myIterations );
         Rfc2898DeriveBytes ^ k2 = gcnew Rfc2898DeriveBytes( pwd1,salt1 );

         // Encrypt the data.
         TripleDES^ encAlg = TripleDES::Create();
         encAlg->Key = k1->GetBytes( 16 );
         MemoryStream^ encryptionStream = gcnew MemoryStream;
         CryptoStream^ encrypt = gcnew CryptoStream( encryptionStream,encAlg->CreateEncryptor(),CryptoStreamMode::Write );
         array<Byte>^utfD1 = (gcnew System::Text::UTF8Encoding( false ))->GetBytes( data1 );

         encrypt->Write( utfD1, 0, utfD1->Length );
         encrypt->FlushFinalBlock();
         encrypt->Close();
         array<Byte>^edata1 = encryptionStream->ToArray();
         k1->Reset();

         // Try to decrypt, thus showing it can be round-tripped.
         TripleDES^ decAlg = TripleDES::Create();
         decAlg->Key = k2->GetBytes( 16 );
         decAlg->IV = encAlg->IV;
         MemoryStream^ decryptionStreamBacking = gcnew MemoryStream;
         CryptoStream^ decrypt = gcnew CryptoStream( decryptionStreamBacking,decAlg->CreateDecryptor(),CryptoStreamMode::Write );

         decrypt->Write( edata1, 0, edata1->Length );
         decrypt->Flush();
         decrypt->Close();
         k2->Reset();

         String^ data2 = (gcnew UTF8Encoding( false ))->GetString( decryptionStreamBacking->ToArray() );
         if (  !data1->Equals( data2 ) )
         {
            Console::WriteLine( "Error: The two values are not equal." );
         }
         else
         {
            Console::WriteLine( "The two values are equal." );
            Console::WriteLine( "k1 iterations: {0}", k1->IterationCount );
            Console::WriteLine( "k2 iterations: {0}", k2->IterationCount );
         }
      }

      catch ( Exception^ e ) 
      {
         Console::WriteLine( "Error: ", e );
      }
   }
}
using System;
using System.IO;
using System.Text;
using System.Security.Cryptography;

public class rfc2898test
{
    // Generate a key k1 with password pwd1 and salt salt1.
    // Generate a key k2 with password pwd1 and salt salt1.
    // Encrypt data1 with key k1 using symmetric encryption, creating edata1.
    // Decrypt edata1 with key k2 using symmetric decryption, creating data2.
    // data2 should equal data1.

    private const string usageText = "Usage: RFC2898 <password>\nYou must 
specify the password for encryption.\n";
    public static void Main(string[] passwordargs)
    {
        //If no file name is specified, write usage text.
        if (passwordargs.Length == 0)
        {
            Console.WriteLine(usageText);
        }
        else
        {
            string pwd1 = passwordargs[0];
            // Create a byte array to hold the random value. 
            byte[] salt1 = new byte[8];
            using (RNGCryptoServiceProvider rngCsp = new 
RNGCryptoServiceProvider())
            {
                // Fill the array with a random value.
                rngCsp.GetBytes(salt1);
            }

            //data1 can be a string or contents of a file.
            string data1 = "Some test data";
            //The default iteration count is 1000 so the two methods use the 
same iteration count.
            int myIterations = 1000;
            try
            {
                Rfc2898DeriveBytes k1 = new Rfc2898DeriveBytes(pwd1, salt1, 
myIterations);
                Rfc2898DeriveBytes k2 = new Rfc2898DeriveBytes(pwd1, salt1);
                // Encrypt the data.
                TripleDES encAlg = TripleDES.Create();
                encAlg.Key = k1.GetBytes(16);
                MemoryStream encryptionStream = new MemoryStream();
                CryptoStream encrypt = new CryptoStream(encryptionStream, 
encAlg.CreateEncryptor(), CryptoStreamMode.Write);
                byte[] utfD1 = new System.Text.UTF8Encoding(false).GetBytes(
data1);

                encrypt.Write(utfD1, 0, utfD1.Length);
                encrypt.FlushFinalBlock();
                encrypt.Close();
                byte[] edata1 = encryptionStream.ToArray();
                k1.Reset();

                // Try to decrypt, thus showing it can be round-tripped.
                TripleDES decAlg = TripleDES.Create();
                decAlg.Key = k2.GetBytes(16);
                decAlg.IV = encAlg.IV;
                MemoryStream decryptionStreamBacking = new MemoryStream();
                CryptoStream decrypt = new CryptoStream(
decryptionStreamBacking, decAlg.CreateDecryptor(), CryptoStreamMode.Write);
                decrypt.Write(edata1, 0, edata1.Length);
                decrypt.Flush();
                decrypt.Close();
                k2.Reset();
                string data2 = new UTF8Encoding(false).GetString(
decryptionStreamBacking.ToArray());

                if (!data1.Equals(data2))
                {
                    Console.WriteLine("Error: The two values are not equal.");
                }
                else
                {
                    Console.WriteLine("The two values are equal.");
                    Console.WriteLine("k1 iterations: {0}", k1.IterationCount);
                    Console.WriteLine("k2 iterations: {0}", k2.IterationCount);
                }
            }
            catch (Exception e)
            {
                Console.WriteLine("Error: ", e);
            }

        }
    }
}
Imports System.IO
Imports System.Text
Imports System.Security.Cryptography



Public Class rfc2898test
    ' Generate a key k1 with password pwd1 and salt salt1.
    ' Generate a key k2 with password pwd1 and salt salt1.
    ' Encrypt data1 with key k1 using symmetric encryption, creating edata1.
    ' Decrypt edata1 with key k2 using symmetric decryption, creating data2.
    ' data2 should equal data1.
    Private Const usageText As String = "Usage: RFC2898 <password>" + vbLf + "You must specify the password for encryption." + vbLf

    Public Shared Sub Main(ByVal passwordargs() As String)
        'If no file name is specified, write usage text.
        If passwordargs.Length = 0 Then
            Console.WriteLine(usageText)
        Else
            Dim pwd1 As String = passwordargs(0)

            Dim salt1(8) As Byte
            Using rngCsp As New RNGCryptoServiceProvider()
                rngCsp.GetBytes(salt1)
            End Using
            'data1 can be a string or contents of a file.
            Dim data1 As String = "Some test data"
            'The default iteration count is 1000 so the two methods use the same iteration count.
            Dim myIterations As Integer = 1000
            Try
                Dim k1 As New Rfc2898DeriveBytes(pwd1, salt1, myIterations)
                Dim k2 As New Rfc2898DeriveBytes(pwd1, salt1)
                ' Encrypt the data.
                Dim encAlg As TripleDES = TripleDES.Create()
                encAlg.Key = k1.GetBytes(16)
                Dim encryptionStream As New MemoryStream()
                Dim encrypt As New CryptoStream(encryptionStream, encAlg.CreateEncryptor(), CryptoStreamMode.Write)
                Dim utfD1 As Byte() = New System.Text.UTF8Encoding(False).GetBytes(data1)
                encrypt.Write(utfD1, 0, utfD1.Length)
                encrypt.FlushFinalBlock()
                encrypt.Close()
                Dim edata1 As Byte() = encryptionStream.ToArray()
                k1.Reset()

                ' Try to decrypt, thus showing it can be round-tripped.
                Dim decAlg As TripleDES = TripleDES.Create()
                decAlg.Key = k2.GetBytes(16)
                decAlg.IV = encAlg.IV
                Dim decryptionStreamBacking As New MemoryStream()
                Dim decrypt As New CryptoStream(decryptionStreamBacking, decAlg.CreateDecryptor(), CryptoStreamMode.Write)
                decrypt.Write(edata1, 0, edata1.Length)
                decrypt.Flush()
                decrypt.Close()
                k2.Reset()
                Dim data2 As String = New UTF8Encoding(False).GetString(decryptionStreamBacking.ToArray())

                If Not data1.Equals(data2) Then
                    Console.WriteLine("Error: The two values are not equal.")
                Else
                    Console.WriteLine("The two values are equal.")
                    Console.WriteLine("k1 iterations: {0}", k1.IterationCount)
                    Console.WriteLine("k2 iterations: {0}", k2.IterationCount)
                End If
            Catch e As Exception
                Console.WriteLine("Error: ", e)
            End Try
        End If

    End Sub
End Class

Remarks

The salt size must be 8 bytes or larger.

RFC 2898 includes methods for creating a key and initialization vector (IV) from a password and salt. You can use PBKDF2, a password-based key derivation function, to derive keys using a pseudo-random function that allows keys of virtually unlimited length to be generated. The Rfc2898DeriveBytes class can be used to produce a derived key from a base key and other parameters. In a password-based key derivation function, the base key is a password and the other parameters are a salt value and an iteration count.

For more information about PBKDF2, see RFC 2898, "PKCS #5: Password-Based Cryptography Specification Version 2.0," available on the Request for Comments Web site. See section 5.2, "PBKDF2," for complete details.

Important

Never hard-code a password within your source code. Hard-coded passwords can be retrieved from an assembly by using the Ildasm.exe (IL Disassembler), by using a hexadecimal editor, or by simply opening up the assembly in a text editor such as Notepad.exe.

See also

Rfc2898DeriveBytes(String, Int32) Rfc2898DeriveBytes(String, Int32) Rfc2898DeriveBytes(String, Int32) Rfc2898DeriveBytes(String, Int32)

Initializes a new instance of the Rfc2898DeriveBytes class using the password and salt size to derive the key.

public:
 Rfc2898DeriveBytes(System::String ^ password, int saltSize);
public Rfc2898DeriveBytes (string password, int saltSize);
new System.Security.Cryptography.Rfc2898DeriveBytes : string * int -> System.Security.Cryptography.Rfc2898DeriveBytes
Public Sub New (password As String, saltSize As Integer)

Parameters

password
String String String String

The password used to derive the key.

saltSize
Int32 Int32 Int32 Int32

The size of the random salt that you want the class to generate.

Exceptions

The specified salt size is smaller than 8 bytes.

Remarks

The salt size must be 8 bytes or larger.

RFC 2898 includes methods for creating a key and initialization vector (IV) from a password and salt. You can use PBKDF2, a password-based key derivation function, to derive keys using a pseudo-random function that allows keys of virtually unlimited length to be generated. The Rfc2898DeriveBytes class can be used to produce a derived key from a base key and other parameters. In a password-based key derivation function, the base key is a password and the other parameters are a salt value and an iteration count.

For more information about PBKDF2, see RFC 2898, "PKCS #5: Password-Based Cryptography Specification Version 2.0," available on the Request for Comments Web site. See section 5.2, "PBKDF2," for complete details.

Important

Never hard-code a password within your source code. Hard-coded passwords can be retrieved from an assembly by using the Ildasm.exe (IL Disassembler), by using a hexadecimal editor, or by simply opening up the assembly in a text editor such as Notepad.exe.

See also

Rfc2898DeriveBytes(Byte[], Byte[], Int32) Rfc2898DeriveBytes(Byte[], Byte[], Int32) Rfc2898DeriveBytes(Byte[], Byte[], Int32) Rfc2898DeriveBytes(Byte[], Byte[], Int32)

Initializes a new instance of the Rfc2898DeriveBytes class using a password, a salt, and number of iterations to derive the key.

public:
 Rfc2898DeriveBytes(cli::array <System::Byte> ^ password, cli::array <System::Byte> ^ salt, int iterations);
public Rfc2898DeriveBytes (byte[] password, byte[] salt, int iterations);
new System.Security.Cryptography.Rfc2898DeriveBytes : byte[] * byte[] * int -> System.Security.Cryptography.Rfc2898DeriveBytes
Public Sub New (password As Byte(), salt As Byte(), iterations As Integer)

Parameters

password
Byte[]

The password used to derive the key.

salt
Byte[]

The key salt used to derive the key.

iterations
Int32 Int32 Int32 Int32

The number of iterations for the operation.

Exceptions

The specified salt size is smaller than 8 bytes or the iteration count is less than 1.

Remarks

The salt size must be 8 bytes or larger and the iteration count must be greater than zero. The minimum recommended number of iterations is 1000.

RFC 2898 includes methods for creating a key and initialization vector (IV) from a password and salt. You can use PBKDF2, a password-based key derivation function, to derive keys using a pseudo-random function that allows keys of virtually unlimited length to be generated. The Rfc2898DeriveBytes class can be used to produce a derived key from a base key and other parameters. In a password-based key derivation function, the base key is a password and the other parameters are a salt value and an iteration count.

For more information about PBKDF2, see RFC 2898, "PKCS #5: Password-Based Cryptography Specification Version 2.0," available on the Request for Comments Web site. See section 5.2, "PBKDF2," for complete details.

Important

Never hard-code a password within your source code. Hard-coded passwords can be retrieved from an assembly by using the Ildasm.exe (IL Disassembler), by using a hexadecimal editor, or by simply opening up the assembly in a text editor such as Notepad.exe.

Rfc2898DeriveBytes(String, Byte[], Int32) Rfc2898DeriveBytes(String, Byte[], Int32) Rfc2898DeriveBytes(String, Byte[], Int32) Rfc2898DeriveBytes(String, Byte[], Int32)

Initializes a new instance of the Rfc2898DeriveBytes class using a password, a salt, and number of iterations to derive the key.

public:
 Rfc2898DeriveBytes(System::String ^ password, cli::array <System::Byte> ^ salt, int iterations);
public Rfc2898DeriveBytes (string password, byte[] salt, int iterations);
new System.Security.Cryptography.Rfc2898DeriveBytes : string * byte[] * int -> System.Security.Cryptography.Rfc2898DeriveBytes
Public Sub New (password As String, salt As Byte(), iterations As Integer)

Parameters

password
String String String String

The password used to derive the key.

salt
Byte[]

The key salt used to derive the key.

iterations
Int32 Int32 Int32 Int32

The number of iterations for the operation.

Exceptions

The specified salt size is smaller than 8 bytes or the iteration count is less than 1.

Examples

The following code example uses the Rfc2898DeriveBytes class to create two identical keys for the TripleDES class. It then encrypts and decrypts some data using the keys.

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

// Generate a key k1 with password pwd1 and salt salt1.
// Generate a key k2 with password pwd1 and salt salt1.
// Encrypt data1 with key k1 using symmetric encryption, creating edata1.
// Decrypt edata1 with key k2 using symmetric decryption, creating data2.
// data2 should equal data1.

int main()
{
   array<String^>^passwordargs = Environment::GetCommandLineArgs();
   String^ usageText = "Usage: RFC2898 <password>\nYou must specify the password for encryption.\n";

   //If no file name is specified, write usage text.
   if ( passwordargs->Length == 1 )
   {
      Console::WriteLine( usageText );
   }
   else
   {
      String^ pwd1 = passwordargs[ 1 ];
      
      array<Byte>^salt1 = gcnew array<Byte>(8);
	  RNGCryptoServiceProvider ^ rngCsp = gcnew RNGCryptoServiceProvider();
		 rngCsp->GetBytes(salt1);
      //data1 can be a string or contents of a file.
      String^ data1 = "Some test data";

      //The default iteration count is 1000 so the two methods use the same iteration count.
      int myIterations = 1000;

      try
      {
         Rfc2898DeriveBytes ^ k1 = gcnew Rfc2898DeriveBytes( pwd1,salt1,myIterations );
         Rfc2898DeriveBytes ^ k2 = gcnew Rfc2898DeriveBytes( pwd1,salt1 );

         // Encrypt the data.
         TripleDES^ encAlg = TripleDES::Create();
         encAlg->Key = k1->GetBytes( 16 );
         MemoryStream^ encryptionStream = gcnew MemoryStream;
         CryptoStream^ encrypt = gcnew CryptoStream( encryptionStream,encAlg->CreateEncryptor(),CryptoStreamMode::Write );
         array<Byte>^utfD1 = (gcnew System::Text::UTF8Encoding( false ))->GetBytes( data1 );

         encrypt->Write( utfD1, 0, utfD1->Length );
         encrypt->FlushFinalBlock();
         encrypt->Close();
         array<Byte>^edata1 = encryptionStream->ToArray();
         k1->Reset();

         // Try to decrypt, thus showing it can be round-tripped.
         TripleDES^ decAlg = TripleDES::Create();
         decAlg->Key = k2->GetBytes( 16 );
         decAlg->IV = encAlg->IV;
         MemoryStream^ decryptionStreamBacking = gcnew MemoryStream;
         CryptoStream^ decrypt = gcnew CryptoStream( decryptionStreamBacking,decAlg->CreateDecryptor(),CryptoStreamMode::Write );

         decrypt->Write( edata1, 0, edata1->Length );
         decrypt->Flush();
         decrypt->Close();
         k2->Reset();

         String^ data2 = (gcnew UTF8Encoding( false ))->GetString( decryptionStreamBacking->ToArray() );
         if (  !data1->Equals( data2 ) )
         {
            Console::WriteLine( "Error: The two values are not equal." );
         }
         else
         {
            Console::WriteLine( "The two values are equal." );
            Console::WriteLine( "k1 iterations: {0}", k1->IterationCount );
            Console::WriteLine( "k2 iterations: {0}", k2->IterationCount );
         }
      }

      catch ( Exception^ e ) 
      {
         Console::WriteLine( "Error: ", e );
      }
   }
}
using System;
using System.IO;
using System.Text;
using System.Security.Cryptography;

public class rfc2898test
{
    // Generate a key k1 with password pwd1 and salt salt1.
    // Generate a key k2 with password pwd1 and salt salt1.
    // Encrypt data1 with key k1 using symmetric encryption, creating edata1.
    // Decrypt edata1 with key k2 using symmetric decryption, creating data2.
    // data2 should equal data1.

    private const string usageText = "Usage: RFC2898 <password>\nYou must 
specify the password for encryption.\n";
    public static void Main(string[] passwordargs)
    {
        //If no file name is specified, write usage text.
        if (passwordargs.Length == 0)
        {
            Console.WriteLine(usageText);
        }
        else
        {
            string pwd1 = passwordargs[0];
            // Create a byte array to hold the random value. 
            byte[] salt1 = new byte[8];
            using (RNGCryptoServiceProvider rngCsp = new 
RNGCryptoServiceProvider())
            {
                // Fill the array with a random value.
                rngCsp.GetBytes(salt1);
            }

            //data1 can be a string or contents of a file.
            string data1 = "Some test data";
            //The default iteration count is 1000 so the two methods use the 
same iteration count.
            int myIterations = 1000;
            try
            {
                Rfc2898DeriveBytes k1 = new Rfc2898DeriveBytes(pwd1, salt1, 
myIterations);
                Rfc2898DeriveBytes k2 = new Rfc2898DeriveBytes(pwd1, salt1);
                // Encrypt the data.
                TripleDES encAlg = TripleDES.Create();
                encAlg.Key = k1.GetBytes(16);
                MemoryStream encryptionStream = new MemoryStream();
                CryptoStream encrypt = new CryptoStream(encryptionStream, 
encAlg.CreateEncryptor(), CryptoStreamMode.Write);
                byte[] utfD1 = new System.Text.UTF8Encoding(false).GetBytes(
data1);

                encrypt.Write(utfD1, 0, utfD1.Length);
                encrypt.FlushFinalBlock();
                encrypt.Close();
                byte[] edata1 = encryptionStream.ToArray();
                k1.Reset();

                // Try to decrypt, thus showing it can be round-tripped.
                TripleDES decAlg = TripleDES.Create();
                decAlg.Key = k2.GetBytes(16);
                decAlg.IV = encAlg.IV;
                MemoryStream decryptionStreamBacking = new MemoryStream();
                CryptoStream decrypt = new CryptoStream(
decryptionStreamBacking, decAlg.CreateDecryptor(), CryptoStreamMode.Write);
                decrypt.Write(edata1, 0, edata1.Length);
                decrypt.Flush();
                decrypt.Close();
                k2.Reset();
                string data2 = new UTF8Encoding(false).GetString(
decryptionStreamBacking.ToArray());

                if (!data1.Equals(data2))
                {
                    Console.WriteLine("Error: The two values are not equal.");
                }
                else
                {
                    Console.WriteLine("The two values are equal.");
                    Console.WriteLine("k1 iterations: {0}", k1.IterationCount);
                    Console.WriteLine("k2 iterations: {0}", k2.IterationCount);
                }
            }
            catch (Exception e)
            {
                Console.WriteLine("Error: ", e);
            }

        }
    }
}
Imports System.IO
Imports System.Text
Imports System.Security.Cryptography



Public Class rfc2898test
    ' Generate a key k1 with password pwd1 and salt salt1.
    ' Generate a key k2 with password pwd1 and salt salt1.
    ' Encrypt data1 with key k1 using symmetric encryption, creating edata1.
    ' Decrypt edata1 with key k2 using symmetric decryption, creating data2.
    ' data2 should equal data1.
    Private Const usageText As String = "Usage: RFC2898 <password>" + vbLf + "You must specify the password for encryption." + vbLf

    Public Shared Sub Main(ByVal passwordargs() As String)
        'If no file name is specified, write usage text.
        If passwordargs.Length = 0 Then
            Console.WriteLine(usageText)
        Else
            Dim pwd1 As String = passwordargs(0)

            Dim salt1(8) As Byte
            Using rngCsp As New RNGCryptoServiceProvider()
                rngCsp.GetBytes(salt1)
            End Using
            'data1 can be a string or contents of a file.
            Dim data1 As String = "Some test data"
            'The default iteration count is 1000 so the two methods use the same iteration count.
            Dim myIterations As Integer = 1000
            Try
                Dim k1 As New Rfc2898DeriveBytes(pwd1, salt1, myIterations)
                Dim k2 As New Rfc2898DeriveBytes(pwd1, salt1)
                ' Encrypt the data.
                Dim encAlg As TripleDES = TripleDES.Create()
                encAlg.Key = k1.GetBytes(16)
                Dim encryptionStream As New MemoryStream()
                Dim encrypt As New CryptoStream(encryptionStream, encAlg.CreateEncryptor(), CryptoStreamMode.Write)
                Dim utfD1 As Byte() = New System.Text.UTF8Encoding(False).GetBytes(data1)
                encrypt.Write(utfD1, 0, utfD1.Length)
                encrypt.FlushFinalBlock()
                encrypt.Close()
                Dim edata1 As Byte() = encryptionStream.ToArray()
                k1.Reset()

                ' Try to decrypt, thus showing it can be round-tripped.
                Dim decAlg As TripleDES = TripleDES.Create()
                decAlg.Key = k2.GetBytes(16)
                decAlg.IV = encAlg.IV
                Dim decryptionStreamBacking As New MemoryStream()
                Dim decrypt As New CryptoStream(decryptionStreamBacking, decAlg.CreateDecryptor(), CryptoStreamMode.Write)
                decrypt.Write(edata1, 0, edata1.Length)
                decrypt.Flush()
                decrypt.Close()
                k2.Reset()
                Dim data2 As String = New UTF8Encoding(False).GetString(decryptionStreamBacking.ToArray())

                If Not data1.Equals(data2) Then
                    Console.WriteLine("Error: The two values are not equal.")
                Else
                    Console.WriteLine("The two values are equal.")
                    Console.WriteLine("k1 iterations: {0}", k1.IterationCount)
                    Console.WriteLine("k2 iterations: {0}", k2.IterationCount)
                End If
            Catch e As Exception
                Console.WriteLine("Error: ", e)
            End Try
        End If

    End Sub
End Class

Remarks

The salt size must be 8 bytes or larger and the iteration count must be greater than zero. The minimum recommended number of iterations is 1000.

RFC 2898 includes methods for creating a key and initialization vector (IV) from a password and salt. You can use PBKDF2, a password-based key derivation function, to derive keys using a pseudo-random function that allows keys of virtually unlimited length to be generated. The Rfc2898DeriveBytes class can be used to produce a derived key from a base key and other parameters. In a password-based key derivation function, the base key is a password and the other parameters are a salt value and an iteration count.

For more information about PBKDF2, see RFC 2898, "PKCS #5: Password-Based Cryptography Specification Version 2.0," available on the Request for Comments Web site. See section 5.2, "PBKDF2," for complete details.

Important

Never hard-code a password within your source code. Hard-coded passwords can be retrieved from an assembly by using the Ildasm.exe (IL Disassembler), by using a hexadecimal editor, or by simply opening up the assembly in a text editor such as Notepad.exe.

See also

Rfc2898DeriveBytes(String, Int32, Int32) Rfc2898DeriveBytes(String, Int32, Int32) Rfc2898DeriveBytes(String, Int32, Int32) Rfc2898DeriveBytes(String, Int32, Int32)

Initializes a new instance of the Rfc2898DeriveBytes class using a password, a salt size, and number of iterations to derive the key.

public:
 Rfc2898DeriveBytes(System::String ^ password, int saltSize, int iterations);
public Rfc2898DeriveBytes (string password, int saltSize, int iterations);
new System.Security.Cryptography.Rfc2898DeriveBytes : string * int * int -> System.Security.Cryptography.Rfc2898DeriveBytes
Public Sub New (password As String, saltSize As Integer, iterations As Integer)

Parameters

password
String String String String

The password used to derive the key.

saltSize
Int32 Int32 Int32 Int32

The size of the random salt that you want the class to generate.

iterations
Int32 Int32 Int32 Int32

The number of iterations for the operation.

Exceptions

The specified salt size is smaller than 8 bytes or the iteration count is less than 1.

iterations is out of range. This parameter requires a non-negative number.

Remarks

The salt size must be 8 bytes or larger and the iteration count must be greater than zero. The minimum recommended number of iterations is 1000.

RFC 2898 includes methods for creating a key and initialization vector (IV) from a password and salt. You can use PBKDF2, a password-based key derivation function, to derive keys using a pseudo-random function that allows keys of virtually unlimited length to be generated. The Rfc2898DeriveBytes class can be used to produce a derived key from a base key and other parameters. In a password-based key derivation function, the base key is a password and the other parameters are a salt value and an iteration count.

For more information on PBKDF2, see RFC 2898,"PKCS #5: Password-Based Cryptography Specification Version 2.0," available on the Request for Comments Web site. See section 5.2, "PBKDF2," for complete details.

Important

Never hard-code a password within your source code. Hard-coded passwords can be retrieved from an assembly by using the Ildasm.exe (IL Disassembler), by using a hexadecimal editor, or by simply opening up the assembly in a text editor such as Notepad.exe.

See also

Rfc2898DeriveBytes(Byte[], Byte[], Int32, HashAlgorithmName) Rfc2898DeriveBytes(Byte[], Byte[], Int32, HashAlgorithmName) Rfc2898DeriveBytes(Byte[], Byte[], Int32, HashAlgorithmName) Rfc2898DeriveBytes(Byte[], Byte[], Int32, HashAlgorithmName)

Initializes a new instance of the Rfc2898DeriveBytes class using the specified password, salt, number of iterations and the hash algorithm name to derive the key.

public:
 Rfc2898DeriveBytes(cli::array <System::Byte> ^ password, cli::array <System::Byte> ^ salt, int iterations, System::Security::Cryptography::HashAlgorithmName hashAlgorithm);
public Rfc2898DeriveBytes (byte[] password, byte[] salt, int iterations, System.Security.Cryptography.HashAlgorithmName hashAlgorithm);
new System.Security.Cryptography.Rfc2898DeriveBytes : byte[] * byte[] * int * System.Security.Cryptography.HashAlgorithmName -> System.Security.Cryptography.Rfc2898DeriveBytes
Public Sub New (password As Byte(), salt As Byte(), iterations As Integer, hashAlgorithm As HashAlgorithmName)

Parameters

password
Byte[]

The password to use to derive the key.

salt
Byte[]

The key salt to use to derive the key.

iterations
Int32 Int32 Int32 Int32

The number of iterations for the operation.

hashAlgorithm
HashAlgorithmName HashAlgorithmName HashAlgorithmName HashAlgorithmName

The hash algorithm to use to derive the key.

Exceptions

The Name property of hashAlgorithm is either null or Empty.

Rfc2898DeriveBytes(String, Byte[], Int32, HashAlgorithmName) Rfc2898DeriveBytes(String, Byte[], Int32, HashAlgorithmName) Rfc2898DeriveBytes(String, Byte[], Int32, HashAlgorithmName) Rfc2898DeriveBytes(String, Byte[], Int32, HashAlgorithmName)

Initializes a new instance of the Rfc2898DeriveBytes class using the specified password, salt, number of iterations and the hash algorithm name to derive the key.

public:
 Rfc2898DeriveBytes(System::String ^ password, cli::array <System::Byte> ^ salt, int iterations, System::Security::Cryptography::HashAlgorithmName hashAlgorithm);
public Rfc2898DeriveBytes (string password, byte[] salt, int iterations, System.Security.Cryptography.HashAlgorithmName hashAlgorithm);
new System.Security.Cryptography.Rfc2898DeriveBytes : string * byte[] * int * System.Security.Cryptography.HashAlgorithmName -> System.Security.Cryptography.Rfc2898DeriveBytes
Public Sub New (password As String, salt As Byte(), iterations As Integer, hashAlgorithm As HashAlgorithmName)

Parameters

password
String String String String

The password to use to derive the key.

salt
Byte[]

The key salt to use to derive the key.

iterations
Int32 Int32 Int32 Int32

The number of iterations for the operation.

hashAlgorithm
HashAlgorithmName HashAlgorithmName HashAlgorithmName HashAlgorithmName

The hash algorithm to use to derive the key.

Exceptions

The Name property of hashAlgorithm is either null or Empty.

Rfc2898DeriveBytes(String, Int32, Int32, HashAlgorithmName) Rfc2898DeriveBytes(String, Int32, Int32, HashAlgorithmName) Rfc2898DeriveBytes(String, Int32, Int32, HashAlgorithmName) Rfc2898DeriveBytes(String, Int32, Int32, HashAlgorithmName)

Initializes a new instance of the Rfc2898DeriveBytes class using the specified password, salt size, number of iterations and the hash algorithm name to derive the key.

public:
 Rfc2898DeriveBytes(System::String ^ password, int saltSize, int iterations, System::Security::Cryptography::HashAlgorithmName hashAlgorithm);
public Rfc2898DeriveBytes (string password, int saltSize, int iterations, System.Security.Cryptography.HashAlgorithmName hashAlgorithm);
new System.Security.Cryptography.Rfc2898DeriveBytes : string * int * int * System.Security.Cryptography.HashAlgorithmName -> System.Security.Cryptography.Rfc2898DeriveBytes
Public Sub New (password As String, saltSize As Integer, iterations As Integer, hashAlgorithm As HashAlgorithmName)

Parameters

password
String String String String

The password to use to derive the key.

saltSize
Int32 Int32 Int32 Int32

The size of the random salt that you want the class to generate.

iterations
Int32 Int32 Int32 Int32

The number of iterations for the operation.

hashAlgorithm
HashAlgorithmName HashAlgorithmName HashAlgorithmName HashAlgorithmName

The hash algorithm to use to derive the key.

Exceptions

The Name property of hashAlgorithm is either null or Empty.

Applies to