Re: ??Difference Between utf8encoder.GetBytes and Encoding.ASCII.GetBytes

From: Phil C. (charlestek_at_rcn.com)
Date: 02/25/05 

Date: Thu, 24 Feb 2005 18:17:52 -0500

Thanks Joe,
It's the usual "too many ways of doing something" make things more complex.
"Joe Kaplan (MVP - ADSI)" <joseph.e.kaplan@removethis.accenture.com> wrote
in message news:%23AgR7NsGFHA.4084@TK2MSFTNGP14.phx.gbl...
> The easiest thing to do is to write some code to test it and see, but I'll
> try to explain too.
>
> UTF8 and Unicode (which is really UTF16 as an encoding) are just two
> different ways to create a binary encoding of a unicode string. UTF8 uses
> a variable number of bytes for each character (depending on the character)
> and UTF16 will use 2 bytes for each character. Since you test string,
> "test", is all ASCII characters, the UTF8 version will be 4 bytes and the
> same as the ASCII version. The Unicode version will be 8 bytes. To see
> differences between ASCII and UTF8, you need to use non-ASCII characters
> in your test.
>
> The various static/shared properties on the Encoding classes are just
> shortcuts to keep you from having to build a new instance of the encoding
> class. Generally, it will always be a little faster to just use them:
>
> Encoding.UTF8
> Encoding.Unicode
>
> HTH,
>
> Joe K.
>
> "Phil C." <charlestek@rcn.com> wrote in message
> news:O1$VxNrGFHA.3628@TK2MSFTNGP15.phx.gbl...
>> Thank you Joe, you saved me a lot of grief.
>> However, then, what is the difference between
>> UTF8Encoding.GetBytes("text")
>> and Encoding.Unicode.GetBytes("text)
>> or the converse
>> UTF8Encoding.GetString(Byte())
>> Encoding.Unicode.GetString(Byte())
>> ??
>>
>> -----------------------------------------------------------------------------------------------------------------------------------------------------
>> "Joe Kaplan (MVP - ADSI)" <joseph.e.kaplan@removethis.accenture.com>
>> wrote in message news:uyWgMXqGFHA.2616@tk2msftngp13.phx.gbl...
>>> Generally speaking, the different encoding classes will give you an
>>> array of bytes from a string corresponding to how that encoding actually
>>> represents a string. Unicode (UTF16) represents each character as 2
>>> bytes. UTF8 will use a variable number of bytes for each character, but
>>> uses only one for ASCII characters, so it generally uses much less space
>>> to store the same Unicode data.
>>>
>>> ASCII converts characters into a single byte using only 7 bits of each
>>> byte. Since it only supports ASCII characters, it can result in data
>>> loss if the string in question contains non-ASCII characters. It rarely
>>> has a use in .NET crypto since strings are unicode in .NET.
>>>
>>> If your encryption key is stored as text, it is probably stored in
>>> Base64. In that case, you probably want to use Convert.FromBase64String
>>> to convert the string key into a byte array.
>>>
>>> Joe K.
>>>
>>> "Phil C." <charlestek@rcn.com> wrote in message
>>> news:u6LpKgpGFHA.2616@tk2msftngp13.phx.gbl...
>>>> Hi. (Using VB.Net) I have a symmetric encryption key stored as text,
>>>> encrytped by DPAPI in my web config that I use a handler
>>>> class to decrypt by the DPAPI and pass to the class that does the
>>>> encryption/decryption.
>>>> The decrypted DPAPI key is a string and needs to be converted to a byte
>>>> array for use by the encryption/decryption class. I'm confused as to
>>>> the difference using utf8encoder.GetBytes() or
>>>> Encoding.ASCII.GetBytes() to do this.
>>>>
>>>> Thanks,
>>>>
>>>> Phil
>>>> Boston, MA
>>>>
>>>
>>>
>>
>>
>
>