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Public Shared Function DecryptPBDK2(ByVal edata As Byte(), ByVal salt As Byte(), ByVal IV As Byte(), ByVal secpswd As SecureString, ByVal iterations As Integer) As Byte()
Dim decrypt As CryptoStream = Nothing
'CryptoStream decrypt = null;
Dim unmanagedPswd As IntPtr = IntPtr.Zero
Dim psbytes As Byte() = New Byte(secpswd.Length) {}
unmanagedPswd = Marshal.SecureStringToGlobalAllocAnsi(secpswd)
Marshal.Copy(unmanagedPswd, psbytes, 0, psbytes.Length)
Marshal.ZeroFreeGlobalAllocAnsi(unmanagedPswd)
Try
Dim kd As Rfc2898DeriveBytes = New Rfc2898DeriveBytes(psbytes, salt, iterations)
Dim decAlg As TripleDES = TripleDES.Create()
decAlg.Key = kd.GetBytes(24)
decAlg.IV = IV
Dim memstr As MemoryStream = New MemoryStream()
decrypt = New CryptoStream(memstr, decAlg.CreateDecryptor(), CryptoStreamMode.Write)
decrypt.Write(edata, 0, edata.Length)
decrypt.Flush()
decrypt.Close() ' this is REQUIRED.
Dim cleartext As Byte() = memstr.ToArray()
Return cleartext
Catch ex As Exception
Console.WriteLine("Problem decrypting: {0}", ex.Message)
Return Nothing
End Try
End Function
Public Shared Function DecodePrivateKeyInfo(ByVal pkcs8 As Byte()) As RSACryptoServiceProvider
'encoded OID sequence for PKCS #1 rsaEncryption szOID_RSA_RSA = "1.2.840.113549.1.1.1"
'this byte[] includes the sequence byte and terminal encoded null
Dim SeqOID As Byte() = {&H30, &HD, &H6, &H9, &H2A, &H86, &H48, &H86, &HF7, &HD, &H1, &H1, &H1, &H5, &H0}
Dim seq As Byte() = New Byte(15) {}
'--------- Set up stream to read the asn.1 encoded SubjectPublicKeyInfo blob ------
Dim mem As MemoryStream = New MemoryStream(pkcs8)
Dim lenstream As Integer = CInt(mem.Length)
Dim binr As BinaryReader = New BinaryReader(mem) 'wrap Memory Stream with BinaryReader for easy reading
Dim bt As Byte = 0
Dim twobytes As UShort = 0
Try
twobytes = binr.ReadUInt16()
If (twobytes = &H8130) Then 'data read as little endian order (actual data order for Sequence is 30 81)
binr.ReadByte() 'advance 1 byte
ElseIf (twobytes = &H8230) Then
binr.ReadInt16() 'advance 2 bytes
Else
Return Nothing
End If
bt = binr.ReadByte()
If (bt <> &H2) Then
Return Nothing
End If
twobytes = binr.ReadUInt16()
If (bt <> &H1) Then
Return Nothing
End If
seq = binr.ReadBytes(15) 'read the Sequence OID
If (Not CompareBytearrays(seq, SeqOID)) Then 'make sure Sequence for OID is correct
Return Nothing
End If
bt = binr.ReadByte()
If (bt <> &H4) Then
Return Nothing
End If
bt = binr.ReadByte() 'read next byte, or next 2 bytes is 0x81 or 0x82; otherwise bt is the byte count
If (bt = &H81) Then
binr.ReadByte()
ElseIf (bt = &H82) Then
binr.ReadUInt16()
End If
'------ at this stage, the remaining sequence should be the RSA private key
Dim rsaprivkey As Byte() = binr.ReadBytes(CInt(lenstream - mem.Position))
Dim rsacsp As RSACryptoServiceProvider = DecodeRSAPrivateKey(rsaprivkey)
Return rsacsp
Catch ex As Exception
Return Nothing
' ''return null;
Finally
binr.Close()
End Try
End Function
Public Shared Function DecodeRSAPrivateKey(ByVal privkey As Byte()) As RSACryptoServiceProvider
Dim MODULUS, E, D, P, Q, DP, DQ, IQ As Byte()
'--------- Set up stream to decode the asn.1 encoded RSA private key ------
Dim mem As MemoryStream = New MemoryStream(privkey)
Dim binr As BinaryReader = New BinaryReader(mem) 'wrap Memory Stream with BinaryReader for easy reading
Dim bt As Byte = 0
Dim twobytes As UShort = 0
Dim elems As Integer = 0
Try
twobytes = binr.ReadUInt16()
If (twobytes = &H8130) Then 'data read as little endian order (actual data order for Sequence is 30 81)
binr.ReadByte() 'advance 1 byte
ElseIf (twobytes = &H8230) Then
binr.ReadInt16() 'advance 2 bytes
Else
Return Nothing
End If
twobytes = binr.ReadUInt16()
If (twobytes <> &H102) Then 'version number
Return Nothing
End If
bt = binr.ReadByte()
If (bt <> &H0) Then
Return Nothing
End If
'------ all private key components are Integer sequences ----
elems = GetIntegerSize(binr)
MODULUS = binr.ReadBytes(elems)
elems = GetIntegerSize(binr)
E = binr.ReadBytes(elems)
elems = GetIntegerSize(binr)
D = binr.ReadBytes(elems)
elems = GetIntegerSize(binr)
P = binr.ReadBytes(elems)
elems = GetIntegerSize(binr)
Q = binr.ReadBytes(elems)
elems = GetIntegerSize(binr)
DP = binr.ReadBytes(elems)
elems = GetIntegerSize(binr)
DQ = binr.ReadBytes(elems)
elems = GetIntegerSize(binr)
IQ = binr.ReadBytes(elems)
Console.WriteLine("showing components ..")
If (verbose) Then
showBytes("\nModulus", MODULUS)
showBytes("\nExponent", E)
showBytes("\nD", D)
showBytes("\nP", P)
showBytes("\nQ", Q)
showBytes("\nDP", DP)
showBytes("\nDQ", DQ)
showBytes("\nIQ", IQ)
End If
'------- create RSACryptoServiceProvider instance and initialize with public key -----
Dim RSA As RSACryptoServiceProvider = New RSACryptoServiceProvider()
Dim RSAparams As RSAParameters = New RSAParameters()
RSAparams.Modulus = MODULUS
RSAparams.Exponent = E
RSAparams.D = D
RSAparams.P = P
RSAparams.Q = Q
RSAparams.DP = DP
RSAparams.DQ = DQ
RSAparams.InverseQ = IQ
RSA.ImportParameters(RSAparams)
Return RSA
Catch ex As Exception
Return Nothing
End Try
binr.Close()
End Function
Public Shared Function GetIntegerSize(ByVal binr As BinaryReader) As Integer
Dim bt As Byte = 0
Dim lowbyte As Byte = &H0
Dim highbyte As Byte = &H0
Dim count As Integer = 0
bt = binr.ReadByte()
If (bt <> &H2) Then 'expect integer
Return 0
End If
bt = binr.ReadByte()
If (bt = &H81) Then
count = binr.ReadByte() 'data size in next byte
ElseIf (bt = &H82) Then
highbyte = binr.ReadByte() 'data size in next 2 bytes
lowbyte = binr.ReadByte()
Dim modint As Byte() = {lowbyte, highbyte, &H0, &H0}
count = BitConverter.ToInt32(modint, 0)
Else
count = bt 'we already have the data size
End If
While (binr.ReadByte() = &H0) 'remove high order zeros in data
count -= 1
End While
binr.BaseStream.Seek(-1, SeekOrigin.Current) 'last ReadByte wasn't a removed zero, so back up a byte
Return count
End Function |