Re: Decrypt problem using Rijndael

you cannot use Unicode to convert between bytes and strings - replace all the conversions with Convert.From/To Base64String

---------------------------------------
Dominick Baier - DevelopMentor
http://www.leastprivilege.com

Hi guys

I'm using an algo to encrypt/decrypt an xml file using Rijndael.
However, SOMETIMES (yea that's right, it does not happen all the
time) the decrypt algo fails when I try to read the data in
cryptostream:

'Read the data out of the crypto stream.
csDecrypt.Read(btOriginalData, 0, btOriginalData.Length)
with the System.Security.Cryptography.CryptographicException "Length
of the data to decrypt is invalid"

I've spent hours unsuccessfully trying to know what's the problem.
Everything seems ok. Here's the code snippet for decrypt. Can anyone
help please?

' Retrieves Key, IV, and data from encrypted file
srKeyFile = New System.IO.StreamReader(DecryptKeyFile,
System.Text.Encoding.Unicode)
sKey = srKeyFile.ReadLine()
sKeyByte = EncUnicode.GetBytes(sKey)
sIV = srKeyFile.ReadLine()
sIVByte = EncUnicode.GetBytes(sIV)
sData = srKeyFile.ReadLine()
sDataByte = EncUnicode.GetBytes(sData)
'Get a decryptor that uses the same key and IV as the
encryptor.
objDecryptor = myRijndael.CreateDecryptor(sKeyByte, sIVByte)
'Now decrypt the previously encrypted message using the
decryptor
obtained.
msDecrypt = New System.IO.MemoryStream(sDataByte)
csDecrypt = New
System.Security.Cryptography.CryptoStream(msDecrypt,
objDecryptor, _

System.Security.Cryptography.CryptoStreamMode.Read)
btOriginalData = New Byte(sDataByte.Length) {}

'Read the data out of the crypto stream. EXCEPTION ON THIS LINE
csDecrypt.Read(btOriginalData, 0, btOriginalData.Length)
'Convert the byte array back into a string.
sXML = EncASCII.GetString(btOriginalData).Replace("&", "&")
Thanks
Jeffrey


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