"Roy Chastain" wrote:

> The example code in the RijndaelManaged class documentation has the
> following
>
> RijndaelManaged myRijndael = new RijndaelManaged ();
>  ICryptoTransform encryptor = myRijndael.CreateEncryptor(key, IV);
>  MemoryStream msEncrypt = new MemoryStream();
>  CryptoStream csEncrypt = new CryptoStream(msEncrypt, encryptor,
>     CryptoStreamMode.Write);
>  toEncrypt = textConverter.GetBytes(original);
> csEncrypt.Write(toEncrypt, 0, toEncrypt.Length);
> csEncrypt.FlushFinalBlock();
> encrypted = msEncrypt.ToArray();
>
> This code is straight forward, but there is a piece of missing
> information.
>
> If I am encrypting multiple messages to a single destination and each
> of these messages are being encrypted with the same key and IV, the I
> BELIEVE that I should use the same instance of RijndaelManaged for
> each message and leave Mode set to ChipherMode.CBC (the default).
>
> I would also ASSUME that I would use the same instance of the
> Encryptor for each message.
>
> What I do not have an idea on is
> 1) -  if I should use the same instance of the CryptoStream for each
> message or create a new CryptoStream for each message.
> 2) - if I can use the same instance of RijndaelManaged for encoding
> and decoding to/from the same destination.  (Not to worry about data
> volume issues.  Key management will be performed independently.)
>
> Thanks
>
>
>            
>
> ------------------------------
> Roy Chastain
> SOHO Technology Solutions, LLC
>

> You can use the same encrypter instance, as this is just the
> functionality working on the CryptoStream objects. The cryptoCtream
> objecs however, contains the actual data being encrypted/decrypted.
>
> Hence - do NOT use the same cryptostream object for each message you
> have in
> your array or list. Create a new CryptoStream object for each message
> to
> encrypt.
> And do remember to call close (or a using statement) on the
> cryptostream
> object.
> "Roy Chastain" wrote:
>
>> The example code in the RijndaelManaged class documentation has the
>> following
>>
>> RijndaelManaged myRijndael = new RijndaelManaged ();
>> ICryptoTransform encryptor = myRijndael.CreateEncryptor(key, IV);
>> MemoryStream msEncrypt = new MemoryStream();
>> CryptoStream csEncrypt = new CryptoStream(msEncrypt, encryptor,
>> CryptoStreamMode.Write);
>> toEncrypt = textConverter.GetBytes(original);
>> csEncrypt.Write(toEncrypt, 0, toEncrypt.Length);
>> csEncrypt.FlushFinalBlock();
>> encrypted = msEncrypt.ToArray();
>> This code is straight forward, but there is a piece of missing
>> information.
>>
>> If I am encrypting multiple messages to a single destination and each
>> of these messages are being encrypted with the same key and IV, the I
>> BELIEVE that I should use the same instance of RijndaelManaged for
>> each message and leave Mode set to ChipherMode.CBC (the default).
>>
>> I would also ASSUME that I would use the same instance of the
>> Encryptor for each message.
>>
>> What I do not have an idea on is
>> 1) -  if I should use the same instance of the CryptoStream for each
>> message or create a new CryptoStream for each message.
>> 2) - if I can use the same instance of RijndaelManaged for encoding
>> and decoding to/from the same destination.  (Not to worry about data
>> volume issues.  Key management will be performed independently.)
>> Thanks
>>
>> ------------------------------
>> Roy Chastain
>> SOHO Technology Solutions, LLC