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Posted: **Wed Sep 25, 2013 8:13 am**

hi, i am trying to encrypt the password string with sharpAESCrypt.dll in my software,wich is building with c#.
for example:

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byte[] byteArr=Encoding.UTF8.GetBytes(password);

stream midAESCrypt=new MemoryStream(byteArr);

stream aesStream= new SharpAESCrypt.SharpAESCrypt(username,midAESCrypt,SharpAESCrypt.OperationMode.Encrypt);
//i use username as the password of AES

but,when i read aesStream, the builder throw error.
i want to know how to read the output stream,and convert it to string. thanks!

Posted: **Wed Sep 25, 2013 7:25 pm**

You are omitting some code, but I assume you are attempting to read the stream that you are supposed to write.

You can only write to a stream that you are encrypting, and you can only read from a stream that you are decrypting. The streams do not support seeking of any kind.

Try using this template, and adapt it to your code:

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byte[] Encrypt(string password, byte[] data)
{
    using(var inputStream = new MemoryStream(data))
    using(var outputStream = new MemoryStream())
    {
        SharpAESCrypt.SharpAESCrypt.Encrypt(password, inputStream, outputStream);
        outputStream.Position = 0;
        return outputStream.ToArray();
    }
}

For this simple usage, you may want to reduce the size of the output by setting these:

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SharpAESCrypt.SharpAESCrypt.Extension_InsertPlaceholder = false;
SharpAESCrypt.SharpAESCrypt.Extension_InsertCreateByIdentifier = false;
SharpAESCrypt.SharpAESCrypt.Extension_InsertTimeStamp = false;

If you want to use the stream, you must use it as a filter that wraps a stream.
For encrypting, you wrap a stream that will be encrypted, and write unencrypted data into it.
For decrypting, you wrap an encrypted stream and read unencrypted data.

To encrypt:

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using(var inputfile = System.IO.File.OpenRead("plaintext.txt"))
using(var outputfile = System.IO.File.OpenWrite("plaintext.txt.aes"))
using(var encStream = new SharpAESCrypt.SharpAESCrypt(password, outputfile, SharpAESCrypt.OperationMode.Encrypt))
    inputfile.CopyTo(encStream);

To decrypt:

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using(var outputfile = System.IO.File.OpenWrite("plaintext.txt"))
using(var inputfile = System.IO.File.OpenRead("plaintext.txt.aes"))
using(var encStream = new SharpAESCrypt.SharpAESCrypt(password, inputfile, SharpAESCrypt.OperationMode.Decrypt))
    encStream.CopyTo(outputfile);

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