Decrypt without save the decryption: possible?

[Federico Bari]

I have to read and encrypted file (with DESCryptoServic eProvider class) and
decrypt it without save the clear file in the disk!!! ie i'd like to have
the decryption in a string variable because for safe reasons i cannot save
the decription in the disk even if for a short time. The CryptoStream seem
to work only with in and out files; do somebody know how i can do? Thank you
very much.

Federico.

[Morten Wennevik]

You can use a memorystream instead of filestream.

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Using M2, Opera's revolutionary e-mail client: http://www.opera.com/m2/

[Jon Skeet [C# MVP]]

Federico Bari <fe********@tis cali.it> wrote:

I have to read and encrypted file (with DESCryptoServic eProvider class) and
decrypt it without save the clear file in the disk!!! ie i'd like to have
the decryption in a string variable because for safe reasons i cannot save
the decription in the disk even if for a short time. The CryptoStream seem
to work only with in and out files; do somebody know how i can do? Thank you
very much.

No, CryptoStreams work with *streams*, not files. You can use a memory
stream, for instance. If you *really* want the result in a string
variable rather than a byte array, I suggest Base64 encoding the binary
data.

--
Jon Skeet - <sk***@pobox.co m>
http://www.pobox.com/~skeet
If replying to the group, please do not mail me too

[aacool]

Jon Skeet [C# MVP] <sk***@pobox.co m> wrote in
news:MP******** *************** *@msnews.micros oft.com:

Federico Bari <fe********@tis cali.it> wrote:

I have to read and encrypted file (with DESCryptoServic eProvider
class) and decrypt it without save the clear file in the disk!!! ie
i'd like to have the decryption in a string variable because for safe
reasons i cannot save the decription in the disk even if for a short
time. The CryptoStream seem to work only with in and out files; do
somebody know how i can do? Thank you very much.

No, CryptoStreams work with *streams*, not files. You can use a memory
stream, for instance. If you *really* want the result in a string
variable rather than a byte array, I suggest Base64 encoding the
binary data.

Please consider the following code, where cryptString is the filetext:

private string DecryptText(str ing cryptString)
{
try
{
SymmetricAlgori thm mCSP;
mCSP = (SymmetricAlgor ithm)(new DESCryptoServic eProvider
());
mCSP.GenerateKe y();
mCSP.GenerateIV ();
ICryptoTransfor m ct = mCSP.CreateDecr yptor
(mCSP.Key,mCSP. IV);
MemoryStream ms = new MemoryStream();
byte[] bytArr = Convert.FromBas e64String(crypt String);
CryptoStream cs = new CryptoStream
(ms,ct,CryptoSt reamMode.Write) ;
//write to cryptostream in memory
cs.Write(bytArr ,0,bytArr.Lengt h);
cs.Flush();
cs.Close();
return System.Text.Enc oding.UTF8.GetS tring(ms.ToArra y
());
}
catch(Exception e)
{
MessageBox.Show (e.Message);
}
return "";
}

This should work as needed.

aacool