RE: DES Encryption/Decryption of Word documents

From: Ivan Medvedev [MS] (ivanmed_at_online.microsoft.com)
Date: 07/10/03

  • Next message: Ivan Medvedev [MS]: "RE: Code Group Question" 
    Date: Wed, 09 Jul 2003 22:07:08 GMT

    Manav -
    The mistake is that you treat the encrypted content as text
    (StreamReader.ReadToEnd returns a string). Encrypted data can be any bytes,
    not necesserily representable by characters. Here is how to fix your
    program: use the following code right after the call to SetKey in your
    decrypt routine:

                            FileStream inputFile = new FileStream(inputFilename, FileMode.Open,
    FileAccess.Read);
                            ICryptoTransform desDecryptor = DES.CreateDecryptor();
                            FileStream fsDecrypted = new FileStream(outputFilename,
    FileMode.OpenOrCreate, FileAccess.Write );
                            CryptoStream cryptostreamDecryptor = new CryptoStream(fsDecrypted,
    desDecryptor, CryptoStreamMode.Write);
            
                            try
                            {
                                    byte[] buffer = new byte[inputFile.Length];
                                    inputFile.Read(buffer, 0, buffer.Length);
                                    cryptostreamDecryptor.Write(buffer, 0, buffer.Length);
                            }

    --Ivan

  • Next message: Ivan Medvedev [MS]: "RE: Code Group Question"

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