IV problems Java -> C#
I have a problem encrypting data in Java to match C# results. Its a RC2 encryption using CBC mode. my problem comes with the IV parameter, cause they (C#) use a 16 byte IV. Ive tried to apply it to my Java code with no luck, using RC2ParameterSpec which only takes the first 8 bytes so the results dont match, and the IvParameterSpec but get an exception when called upon saying it must be 8 bytes long. All documentation ive seen points to 8 byte IVs, so my question is Is it possible to make it work with a 16 byte IV?, if so, how?
[540 byte] By [
krima] at [2007-10-2 20:14:53]
well maybe this will help
here is the C# code :
Private bytIV() As Byte = {123, 231, 20, 6, 70, 45, 24, 67, 8, 65, 32, 45, 154, 222, 144, 43}
Private Const sKey = "Key"
Public Function EncryptText(ByVal sValue As String) As String
Dim bytValue() As Byte
Dim bytKey() As Byte
Dim bytEncoded() As Byte
Dim iLen As Integer, iRemaining As Integer
Dim objMS As New MemoryStream()
Dim objCrypt As CryptoStream
Dim objRM As RC2CryptoServiceProvider
Try
bytValue = Encoding.UTF8.GetBytes(sValue.ToCharArray)
iLen = Len(sKey)
bytKey = Encoding.ASCII.GetBytes(sKey.ToCharArray)
objRM = New RC2CryptoServiceProvider()
objCrypt = New CryptoStream(objMS, objRM.CreateEncryptor(bytKey, bytIV), CryptoStreamMode.Write)
objCrypt.Write(bytValue, 0, bytValue.Length)
objCrypt.FlushFinalBlock()
bytEncoded = objMS.ToArray
objMS.Close()
objCrypt.Close()
Return Convert.ToBase64String(bytEncoded)
Catch err As System.Exception
Throw New Exception("error " & System.Reflection.MethodInfo.GetCurrentMethod.Name & " function:" & err.Message)
Finally
If Not objMS Is Nothing Then objMS.Close()
If Not objCrypt Is Nothing Then objCrypt.Close()
objRM = Nothing
objMS = Nothing
objCrypt = Nothing
End Try
and here is my adaptation in Java
public class RC2 {
public static String execute(String data) {
String instr = data;
String rutenc;
String key = "Key";
byte[] encriptado;
byte[] aEncriptar;
byte[] mikey = key.getBytes();
byte[] iv = {(byte) 123, (byte) 231, (byte) 20, (byte) 6, (byte) 70, (byte) 45, (byte) 24, (byte) 67, (byte) 8, (byte) 65, (byte) 32, (byte) 45, (byte) 154, (byte) 222, (byte) 144, (byte) 43};
try {
SecretKeySpec key = new SecretKeySpec(mikey, "RC2");
RC2ParameterSpec rc2Spec = new RC2ParameterSpec(128, iv);
Cipher cipher = Cipher.getInstance("RC2/CBC/PKCS5Padding");
cipher.init(Cipher.ENCRYPT_MODE, key, rc2Spec);
aEncriptar = instr.getBytes("UTF8");
encriptado = cipher.doFinal(aEncriptar);
rutenc = new BASE64Encoder().encodeBuffer(encriptado);
return(rutenc);
} catch (Exception e) {
System.out.println("Error : " + e);
return(null);
}
}
}
krima at 2007-7-13 22:57:06 >
krim-
That is not C#, its VB.NET. But the libraries are all the same, so its just a
matter of syntax. I dont have a VB.NET compiler or the time to translate
your code right now, but I did throw a couple lines together in C# that
attempts to set a 16-byte IV for RC2. It throws an error.
Unhandled Exception: System.Security.Cryptography.CryptographicException: Specified initialization vector (IV) does not match the block size for this algorithm.
at System.Security.Cryptography.SymmetricAlgorithm.set_IV(Byte[] value)
at RC2_IV.MyMainClass.Main()
Also, checking the length of the IV byte array returns 8.
using System;
using System.IO;
using System.Text;
using System.Security.Cryptography;
namespace RC2_IV {
class MyMainClass {
public static void Main() {
RC2CryptoServiceProvider rc2 = new RC2CryptoServiceProvider();
Console.WriteLine("IV is {0} bytes", rc2.IV.Length);
byte[] iv =
{123, 231, 20, 6, 70, 45, 24, 67,
8, 65, 32, 45, 154, 222, 144, 43};
rc2.IV = iv;
Console.WriteLine("IV = {0}", BitConverter.ToString(rc2.IV));
}
}
}
I dont think the VB side is doing what you think it is. Can you modify to only
use an 8-byte IV. Or try your java code only using the first 8 bytes of the
IV. Maybe the VB side's RC2 Provider class is just taking the first 8 bytes of the array...
