в 16:40, 26 мая 2010

2010-05-26T16:40:06Z

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2010-05-26T12:45:20Z

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==Decrypt a Des Encryted File==

<source lang="vbnet">
Imports System
Imports System.Xml
Imports System.Xml.Schema
Imports System.IO
Imports System.Data.OleDb
Imports System.Data.rumon
Imports System.Data.SqlClient
Imports System.Data
Imports System.Security
Imports System.Security.Cryptography

Public Class MainClass

Shared Sub Main()
Dim fs As FileStream = New FileStream("DSencrypted.dat",FileMode.Create, FileAccess.Write)
Dim MyDS As DataSet = New DataSet()
Dim MyDS2 As DataSet = New DataSet()
Dim Connection As SqlConnection = New SqlConnection("Server=(local)\SQLEXPRESS;Initial Catalog=MyDatabase;Integrated Security=SSPI")
Connection.Open()
Dim MyDA As SqlDataAdapter = New SqlDataAdapter("SELECT * FROM Employee", Connection)
MyDA.Fill(MyDS, "Employee")
Dim DES As DESCryptoServiceProvider = New DESCryptoServiceProvider()
Dim DESencrypter As ICryptoTransform = DES.CreateEncryptor()
Dim cryptStream As CryptoStream = New CryptoStream(fs, DESencrypter, CryptoStreamMode.Write)
MyDS.WriteXml(cryptStream, XmlWriteMode.WriteSchema)
cryptStream.Close()

Dim fsRead As FileStream = New FileStream("DSencrypted.dat", _
FileMode.Open, FileAccess.Read)
Dim DESdecrypter As ICryptoTransform = DES.CreateDecryptor()
Dim decryptStream As CryptoStream = New CryptoStream(fsRead, _
DESdecrypter, CryptoStreamMode.Read)
Dim plainStreamR As XmlTextReader = New XmlTextReader(decryptStream)
MyDS2.ReadXml(plainStreamR, XmlReadMode.ReadSchema)
End Sub
End Class

</source>

==Encrypting a file==

<source lang="vbnet">
Imports System.Security.Cryptography
Module MainModule
Public Function GenerateKey() As Byte()
Dim objDES As New System.Security.Cryptography.DESCryptoServiceProvider()
objDES.GenerateKey()
Return objDES.Key
End Function
Public Function GenerateIV() As Byte()
Dim objDES As New System.Security.Cryptography.DESCryptoServiceProvider()
objDES.GenerateIV()
Return objDES.IV
End Function
Public Sub SaveEncryptedFile(ByVal Key() As Byte, ByVal IV() As Byte, ByVal Data As String, ByVal Filename As String)
Dim objFileStream As New System.IO.FileStream(Filename, System.IO.FileMode.Create, System.IO.FileAccess.Write)
Dim bytInput As Byte() = New System.Text.UnicodeEncoding().GetBytes(Data)
Dim objDES As New DESCryptoServiceProvider()
objDES.Key = Key
objDES.IV = IV
Dim objDESEncrypt As ICryptoTransform = objDES.CreateEncryptor()
Dim objCryptStream As New CryptoStream(objFileStream, objDESEncrypt, CryptoStreamMode.Write)
objCryptStream.Write(bytInput, 0, bytInput.Length)
objCryptStream.Close()
objFileStream.Close()
End Sub
Public Function LoadEncryptedFile(ByVal Key() As Byte, ByVal IV() As Byte, ByVal Filename As String) As String
Dim objFileStream As New System.IO.FileStream(Filename, System.IO.FileMode.Open, System.IO.FileAccess.Read)
Dim objDES As New DESCryptoServiceProvider()
objDES.Key = Key
objDES.IV = IV
Dim objDESDecrypt As ICryptoTransform = objDES.CreateDecryptor()
Dim objCryptStream As New CryptoStream(objFileStream, objDESDecrypt, CryptoStreamMode.Read)
LoadEncryptedFile = New System.IO.StreamReader(objCryptStream, New System.Text.UnicodeEncoding()).ReadToEnd()
objCryptStream.Close()
objFileStream.Close()
End Function
End Module

</source>

==Use DES, RC2, Rijndael, TripleDES to decrypt and Encrypt files==

<source lang="vbnet">
Imports System.Security.Cryptography
Imports System.IO
Imports System.Text
Imports System
Public Class SymEnc
Shared Dim algorithms() As String = {"DES", "RC2", "Rijndael", "TripleDES"}
Shared Dim b64Keys() As String = {"YE32PGCJ/g0=","vct+rJ09WuUcR61yfxniTQ==","PHDPqfwE3z25f2UYjwwfwg4XSqxvl8WYmy+2h8t6AUg=","Q1/lWoraddTH3IXAQUJGDSYDQcYYuOpm"}
Shared Dim b64IVs() As String = {"onQX8hdHeWQ=","jgetiyz+pIc=","pd5mgMMfDI2Gxm/SKl5I8A==","6jpFrUh8FF4="}
Public Shared Sub Main(ByVal CmdArgs() As String)
If (CmdArgs.Length <> 4) Then
UsageAndExit()
End If
Dim algorithmsIndex As Integer = CmdArgs(0)
If (algorithmsIndex < 0 Or algorithmsIndex >= algorithms.Length) Then
UsageAndExit()
End If

Dim inputFile As FileStream = File.OpenRead(CmdArgs(2))
Dim outputFile As FileStream = File.OpenWrite(CmdArgs(3))
Dim sa As SymmetricAlgorithm = SymmetricAlgorithm.Create(algorithms(algorithmsIndex))

sa.IV = Convert.FromBase64String(b64IVs(algorithmsIndex))
sa.Key = Convert.FromBase64String(b64Keys(algorithmsIndex))
If (CmdArgs(1).ToUpper().StartsWith("E")) Then
Encrypt(sa, inputFile, outputFile)
Else
Decrypt(sa, inputFile, outputFile)
End If

End Sub
Shared Public Sub Encrypt(ByVal sa As SymmetricAlgorithm,ByVal inputFile As Stream,ByVal outputFile As Stream)
Dim trans As ICryptoTransform = sa.CreateEncryptor()
Dim buf() As Byte = New Byte(2048) {}
Dim cs As CryptoStream = _
New CryptoStream(outputFile, trans, CryptoStreamMode.Write)
Dim Len As Integer
inputFile.Position = 0
Len = inputFile.Read(buf, 0, buf.Length)
While (Len > 0)
cs.Write(buf, 0, Len)
Len = inputFile.Read(buf, 0, buf.Length)
End While
cs.Close()
inputFile.Close()
End Sub
Shared Public Sub Decrypt(ByVal sa As SymmetricAlgorithm,ByVal inputFile As Stream,ByVal outputFile As Stream)
Dim trans As ICryptoTransform = sa.CreateDecryptor()
Dim buf() As Byte = New Byte(2048) {}
Dim cs As CryptoStream = _
New CryptoStream(inputFile, trans, CryptoStreamMode.Read)
Dim Len As Integer
Len = cs.Read(buf, 0, buf.Length)
While (Len > 0)
outputFile.Write(buf, 0, Len)
Len = cs.Read(buf, 0, buf.Length)
End While
inputFile.Close()
outputFile.Close()
End Sub
Shared Public Sub UsageAndExit()
Console.Write("usage SymEnc <algorithms index> <D|E> <in> <out> ")
Console.WriteLine("D =decrypt, E=Encrypt")
For i As Integer = 0 To (algorithms.Length - 1)
Console.WriteLine("Algo index: {0} {1}", i, algorithms(i))
Next i
End
End Sub
End Class

</source>

==Use Des to cypher and decypher File ==

<source lang="vbnet">
Imports System
Imports System.Windows.Forms
Imports System.Security
Imports System.Security.Cryptography
Imports System.IO
Public Class MainClass
Shared Sub Main()
Dim plainTextFileName As String = "test.txt"
Dim cypherTextFileName As String = "cyphertext.dat"
Dim decypheredFileName As String = "decyphered.txt"
CryptFile("MyPassword", plainTextFileName, cypherTextFileName, True)
Console.WriteLine( File.ReadAllText(plainTextFileName))
Console.WriteLine( File.ReadAllText(cypherTextFileName))
CryptFile("MyPassword", cypherTextFileName, decypheredFileName, False)
Console.WriteLine( File.ReadAllText(decypheredFileName))
End Sub
" Encrypt or decrypt a file, saving the results
" in another file.
Shared Private Sub CryptFile(ByVal password As String, ByVal in_file As String, ByVal out_file As String, ByVal encrypt As Boolean)
" Create input and output file streams.
Dim in_stream As New FileStream(in_file, FileMode.Open, FileAccess.Read)
Dim out_stream As New FileStream(out_file, FileMode.Create, FileAccess.Write)
Dim des_provider As New TripleDESCryptoServiceProvider()
" Find a valid key size for this provider.
Dim key_size_bits As Integer = 0
For i As Integer = 1024 To 1 Step -1
If des_provider.ValidKeySize(i) Then
key_size_bits = i
Exit For
End If
Next i
"Debug.Assert(key_size_bits > 0)
Dim block_size_bits As Integer = des_provider.BlockSize
Dim key As Byte() = Nothing
Dim iv As Byte() = Nothing
MakeKeyAndIV(password, key_size_bits, block_size_bits, key, iv)
Dim crypto_transform As ICryptoTransform
If encrypt Then
crypto_transform = des_provider.CreateEncryptor(key, iv)
Else
crypto_transform = des_provider.CreateDecryptor(key, iv)
End If
Dim crypto_stream As New CryptoStream(out_stream, crypto_transform, CryptoStreamMode.Write)
Const BLOCK_SIZE As Integer = 1024
Dim buffer(BLOCK_SIZE) As Byte
Dim bytes_read As Integer
Do
bytes_read = in_stream.Read(buffer, 0, BLOCK_SIZE)
If bytes_read = 0 Then Exit Do
crypto_stream.Write(buffer, 0, bytes_read)
Loop
crypto_stream.Close()
in_stream.Close()
out_stream.Close()
End Sub
" Use the password to generate key bytes.
Shared Private Sub MakeKeyAndIV(ByVal password As String, ByVal key_size_bits As Integer, ByVal block_size_bits As Integer, ByRef key As Byte(), ByRef iv As Byte())
Dim password_derive_bytes As New PasswordDeriveBytes( _
"MyPassword", Nothing, "SHA384", 1000)
key = password_derive_bytes.GetBytes(key_size_bits \ 8)
iv = password_derive_bytes.GetBytes(block_size_bits \ 8)
End Sub
End Class

</source>

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в 16:40, 26 мая 2010

Admin: 1 версия