AQUI TE DEJO LA CLASE QUE YO USO:
Imports System.Security.Cryptography
Imports System.Text
Imports System.IO
Public Class Seguridad
Private mbytKey(7) As Byte
Private mbytIV(7) As Byte
Private Function convierteLlave(ByVal strLlave As String) As Boolean
Try
Dim bp(strLlave.Length - 1) As Byte
Dim aEnc As ASCIIEncoding = New ASCIIEncoding()
aEnc.GetBytes(strLlave, 0, strLlave.Length, bp, 0)
Dim sha As SHA1CryptoServiceProvider = New SHA1CryptoServiceProvider()
Dim bpHash() As Byte = sha.ComputeHash(bp)
Dim i As Integer
For i = 0 To 7
mbytKey(i) = bpHash(i)
Next i
For i = 8 To 15
mbytIV(i - 8) = bpHash(i)
Next
Return True
Catch e As Exception
Return False
End Try
End Function
Public Function encriptaDato(ByVal strDato As String) As String
Dim strResultado As String
If strDato.Length > 92160 Then
strResultado = "Error. Data String too large. Keep within 90Kb."
Return strResultado
End If
If Not (convierteLlave("LLAVE")) Then
strResultado = "Error. Fail to generate key for encryption"
Return strResultado
End If
strDato = String.Format("{0,5:00000}" & strDato, strDato.Length)
Dim rbData(strDato.Length - 1) As Byte
Dim aEnc As New ASCIIEncoding()
aEnc.GetBytes(strDato, 0, strDato.Length, rbData, 0)
Dim descsp As DESCryptoServiceProvider = New DESCryptoServiceProvider()
Dim desEncrypt As ICryptoTransform = descsp.CreateEncryptor(mbytKey, mbytIV)
Dim mStream As New MemoryStream(rbData)
Dim cs As New CryptoStream(mStream, desEncrypt, CryptoStreamMode.Read)
Dim mOut As New MemoryStream()
Dim bytesRead As Integer
Dim output(1023) As Byte
Do
bytesRead = cs.Read(output, 0, 1024)
If Not (bytesRead = 0) Then
mOut.Write(output, 0, bytesRead)
End If
Loop While (bytesRead > 0)
If mOut.Length = 0 Then
strResultado = ""
Else
strResultado = Convert.ToBase64String(mOut.GetBuffer(), 0, CInt(mOut.Length))
End If
Return strResultado
End Function
Public Function desencriptaDato(ByVal strDato As String) As String
Dim strResultado As String
If Not (convierteLlave("LLAVE")) Then
strResultado = "Error. Fail to generate key for decryption"
Return strResultado
End If
Dim nReturn As Integer = 0
Dim descsp As New DESCryptoServiceProvider()
Dim desDecrypt As ICryptoTransform = descsp.CreateDecryptor(mbytKey, mbytIV)
Dim mOut As New MemoryStream()
Dim cs As New CryptoStream(mOut, desDecrypt, CryptoStreamMode.Write)
Dim bPlain(strDato.Length - 1) As Byte
Try
bPlain = Convert.FromBase64CharArray(strDato.ToCharArray(), 0, strDato.Length)
Catch e As Exception
strResultado = "Error. Input Data is not base64 encoded."
Return strResultado
End Try
Dim lRead As Long = 0
Dim lReadNow As Long = 0
Dim lTotal As Long = strDato.Length
Try
Do While (lTotal >= lRead)
cs.Write(bPlain, 0, bPlain.Length)
lReadNow = CLng(((bPlain.Length / descsp.BlockSize) * descsp.BlockSize))
lRead = lReadNow + lRead
Loop
Dim aEnc As New ASCIIEncoding()
strResultado = aEnc.GetString(mOut.GetBuffer(), 0, CInt(mOut.Length))
Dim strLen As String = strResultado.Substring(0, 5)
Dim nLen As Integer = CInt(strLen)
strResultado = strResultado.Substring(5, nLen)
nReturn = CInt(mOut.Length)
Return strResultado
Catch e As Exception
strResultado = "Error. Decryption Failed. Possibly due to incorrect Key or corrupted data"
End Try
Return strResultado
End Function
End Class
PARA USARLO:
Instancias la clase, y llamas a ecripta o desencripta DATO y le pasas el valor
Estas funciones te retornan el valor encriptado y viceversa.
Espero te sea de utilidad.
