Decrypting a text using Rijndael

[3bood ghzawi]

Hi all, i have been using a Rijndael algorithm to encrypt and decrypt a sequence of bytes, but when i run the code i get the following exeption "Padding is invalid and cannot be removed.", this exeption belongs to decrypt function at line int decryptedByteCount = cryptoStream.Read(pTextBytes, 0, pTextBytes.Length); i writ my code here:

public static byte[] Encrypt(byte[] clearData)
{
System.Configuration.AppSettingsReader settingsReader = new AppSettingsReader();
//Get your key from config file to open the lock!
string key = (string)settingsReader.GetValue("SecurityKey", typeof(String));

        MD5CryptoServiceProvider hashmd5 = new MD5CryptoServiceProvider();
        byte\[\] keyArray = hashmd5.ComputeHash(UTF8Encoding.UTF8.GetBytes(key));
        hashmd5.Clear();

        Rijndael rijKey = Rijndael.Create();
        rijKey.Mode = CipherMode.;
        rijKey.Padding = PaddingMode.PKCS7;
        MemoryStream ms = new MemoryStream();
        CryptoStream cs = new CryptoStream(ms,rijKey.CreateEncryptor(), CryptoStreamMode.Write); 
        cs.Write(clearData, 0, clearData.Length);
        cs.FlushFinalBlock();
        byte\[\] cipherTextBytes = ms.ToArray();
        ms.Close();
        cs.Close();

        return cipherTextBytes;
    }

    public static byte\[\] Decrypt(byte\[\] encryptedData)
    {
        System.Configuration.AppSettingsReader settingsReader = new AppSettingsReader();
        //Get your key from config file to open the lock!
        string key = (string)settingsReader.GetValue("SecurityKey", typeof(String));
        MD5CryptoServiceProvider hashmd5 = new MD5CryptoServiceProvider();
        byte\[\] keyArray = hashmd5.ComputeHash(UTF8Encoding.UTF8.GetBytes(key));
        hashmd5.Clear();

        Rijndael rijKey = Rijndael.Create();
        rijKey.Mode = CipherMode.ECB;
        rijKey.Padding = PaddingMode.PKCS7;
        MemoryStream memoryStream = new MemoryStream(encryptedData);
        CryptoStream cryptoStream = new CryptoStream(memoryStream, rijKey.CreateDecryptor(),
        CryptoStreamMode.Read);
        byte\[\] pTextBytes = new byte\[encryptedData.Length\];
        int decryptedByteCount = cryptoStream.Read(pTextBytes, 0, pTextBytes.Length);
        memoryStream.Close();
        cryptoStream.Close();
        return pTextBytes;
    }

[Not Active]

Format the code. Remove the duplicate post before some replies to it.

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I know the language. I've read a book. - _Madmatt

[Keith Barrow]

Your code is unformatted, you need to ensure that the > & <g; appear, rather than > etc. The problem you are getting is due to extra characters being read from the stream. The length of encrypyted string will always be a multiple of a set length (which itself is a power of two). Our encryption rountine always produces blocks of length 16, So the string "1" as does "12345678901234" would produce an encrypted string 16 hex characters long, "123456789012345" produces 32 character long string. I thnk the actual block size relates to the key and/or the IV value. In this case, for a string to be decrypted, the count of hex characters must be evenly divisible by 16. You are probably either reading past the end of the string in the memory stream, or the stream is including padding characters. In either case, you must stop reading before then.

Dalek Dave: There are many words that some find offensive, Homosexuality, Alcoholism, Religion, Visual Basic, Manchester United, Butter.

[Luc Pattyn]

Hi, you have been around for several months, so you should know code needs to be shown with PRE tags so it keeps its formatting; and posting the same stuff twice isn't acceptable either. Please delete the one without replies, and edit the one heading this thread. :)

Luc Pattyn [Forum Guidelines] [Why QA sucks] [My Articles]

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I only read code that is properly formatted, adding PRE tags is the easiest way to obtain that.
All Toronto weekends should be extremely wet until we get it automated in regular forums, not just QA.

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[Keith Barrow]

Actually, the Pre tags are there, its just that he's used < instead of < I'm assuming he had Encode "<" (and other HTML) characters when pasting ticked.

Dalek Dave: There are many words that some find offensive, Homosexuality, Alcoholism, Religion, Visual Basic, Manchester United, Butter.

[Luc Pattyn]

You're right, I did not notice as I don't look at unformatted code at all... If the poster isn't willing to do the posting right, then he is beyond help as far as I'm concerned. :)

Luc Pattyn [Forum Guidelines] [Why QA sucks] [My Articles]

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I only read code that is properly formatted, adding PRE tags is the easiest way to obtain that.
All Toronto weekends should be extremely wet until we get it automated in regular forums, not just QA.

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