simple encryption

[Beeeeeeeeeeeeves]

Hi
I'm looking for some .net example code on encryption: I don't want anything fancy, no complex third party components with sophisticated algorithms, explanations of principle, or "public/private key" confusion (which seems to be all google can come up with) - I just want a SIMPLE example of how I can encrypt a string and then get back the SAME STRING. I found an example on MSDN which involves compiling a DLL then using it in a test form, but about 1 in 5 times it throws an exception, this isn't good enough for me - I just need it to be simple. It doesn't need to be state of the art defence against hardened crackers, mainly just so it can't be read from glancing at it - not much more. But must be SIMPLE and ALWAYS GIVE THE SAME THING BACK.

Anyone?

[Jon Skeet [C# MVP]]

Beeeeeeeeeeeeve s <Be************ **@discussions. microsoft.com> wrote:

I'm looking for some .net example code on encryption: I don't want
anything fancy, no complex third party components with sophisticated
algorithms, explanations of principle, or "public/private key"
confusion (which seems to be all google can come up with) - I just
want a SIMPLE example of how I can encrypt a string and then get back
the SAME STRING. I found an example on MSDN which involves compiling
a DLL then using it in a test form, but about 1 in 5 times it
throwsan exception, this isn't good enough for me - I just need it to
be simple. It doesn't need to be state of the art defence against hardened
crackers, mainly just so it can't be read from glancing at it - not
much more. But must be SIMPLE and ALWAYS GIVE THE SAME THING BACK.

The docs for CryptoStream give a simple example of encrypting a byte
array. To use strings instead, just use Encoding.UTF8.G etBytes to
transform the string into a byte array, and Encoding.UTF8.G etString to
transform it back after decrypting.

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

[Beeeeeeeeeeeeves]

Cheers for the very quick response.

But why UTF8?

And any link to this example in the docs?

"Jon Skeet [C# MVP]" wrote:

Beeeeeeeeeeeeve s <Be************ **@discussions. microsoft.com> wrote:

I'm looking for some .net example code on encryption: I don't want
anything fancy, no complex third party components with sophisticated
algorithms, explanations of principle, or "public/private key"
confusion (which seems to be all google can come up with) - I just
want a SIMPLE example of how I can encrypt a string and then get back
the SAME STRING. I found an example on MSDN which involves compiling
a DLL then using it in a test form, but about 1 in 5 times it
throwsan exception, this isn't good enough for me - I just need it to
be simple. It doesn't need to be state of the art defence against hardened
crackers, mainly just so it can't be read from glancing at it - not
much more. But must be SIMPLE and ALWAYS GIVE THE SAME THING BACK.

The docs for CryptoStream give a simple example of encrypting a byte
array. To use strings instead, just use Encoding.UTF8.G etBytes to
transform the string into a byte array, and Encoding.UTF8.G etString to
transform it back after decrypting.

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

[Jon Skeet [C# MVP]]

Beeeeeeeeeeeeve s <Be************ **@discussions. microsoft.com> wrote:

Cheers for the very quick response.

But why UTF8?
It's a lossless encoding which is compact for ASCII. If you're using a
lot of non-ASCII, it would make sense to use Encoding.Unicod e instead.
And any link to this example in the docs?

What, to using Encoding.UTF8? Not that I know of. Encryption
fundamentally acts on binary data, and the conversion between binary
data and text data is quite distinct from encryption itself.

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

[LEBRUN Thomas]

Link to the CryptoStream Example (MSDN):

http://msdn.microsoft.com/library/de...ClassTopic.asp

Tom.

"Beeeeeeeeeeeev es" wrote:

Cheers for the very quick response.

But why UTF8?

And any link to this example in the docs?

"Jon Skeet [C# MVP]" wrote:

Beeeeeeeeeeeeve s <Be************ **@discussions. microsoft.com> wrote:

I'm looking for some .net example code on encryption: I don't want
anything fancy, no complex third party components with sophisticated
algorithms, explanations of principle, or "public/private key"
confusion (which seems to be all google can come up with) - I just
want a SIMPLE example of how I can encrypt a string and then get back
the SAME STRING. I found an example on MSDN which involves compiling
a DLL then using it in a test form, but about 1 in 5 times it
throwsan exception, this isn't good enough for me - I just need it to
be simple. It doesn't need to be state of the art defence against hardened
crackers, mainly just so it can't be read from glancing at it - not
much more. But must be SIMPLE and ALWAYS GIVE THE SAME THING BACK.

The docs for CryptoStream give a simple example of encrypting a byte
array. To use strings instead, just use Encoding.UTF8.G etBytes to
transform the string into a byte array, and Encoding.UTF8.G etString to
transform it back after decrypting.

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

[Beeeeeeeeeeeeves]

There may be characters such as digits, but there won't be anything like arabic characters or anything....

"Jon Skeet [C# MVP]" wrote:

Beeeeeeeeeeeeve s <Be************ **@discussions. microsoft.com> wrote:

Cheers for the very quick response.

But why UTF8?

It's a lossless encoding which is compact for ASCII. If you're using a
lot of non-ASCII, it would make sense to use Encoding.Unicod e instead.

And any link to this example in the docs?

What, to using Encoding.UTF8? Not that I know of. Encryption
fundamentally acts on binary data, and the conversion between binary
data and text data is quite distinct from encryption itself.

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

[Beeeeeeeeeeeeves]

I'm confused... what is the difference between Encoding.ASCII. GetBytes and Encoding.UTF8.G etBytes ????

"Jon Skeet [C# MVP]" wrote:

Beeeeeeeeeeeeve s <Be************ **@discussions. microsoft.com> wrote:

Cheers for the very quick response.

But why UTF8?

It's a lossless encoding which is compact for ASCII. If you're using a
lot of non-ASCII, it would make sense to use Encoding.Unicod e instead.

And any link to this example in the docs?

What, to using Encoding.UTF8? Not that I know of. Encryption
fundamentally acts on binary data, and the conversion between binary
data and text data is quite distinct from encryption itself.

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

[Jon Skeet [C# MVP]]

Beeeeeeeeeeeeve s <Be************ **@discussions. microsoft.com> wrote:

I'm confused... what is the difference between
Encoding.ASCII. GetBytes and Encoding.UTF8.G etBytes ????

One uses the ASCII encoding and the other uses UTF-8 - they're very
different encodings, which happen to give the same results for all
ASCII characters.

See http://www.pobox.com/~skeet/csharp/unicode.html for more
information.

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

[Jon Skeet [C# MVP]]

Beeeeeeeeeeeeve s <Be************ **@discussions. microsoft.com> wrote:

At the end of the day, my problem is far from solved. I wanted simple
encryption. What did I get? Confusion.

Here's my pot shot at encrypting... basically I've got a form with
four textboxes: txtPassword (to encrypt), txtEncryptedTex t (for what
it's encrypted to), txtDecryptedTex t (for the decrypted text - sadly
the program never makes it this far) and txtInitializati onVector.

Where am I going wrong, I'm getting weary.

Well, for one thing you've got a MemoryStream for no good reason when
encrypting. You can just use

cs.Write(b_raw, 0, b_raw.Length);

The second thing you're doing wrong is assuming that any random piece
of binary data can be converted to UTF-8 and back losslessly. Just as
the *input* to encryption is binary, so is the output. The easiest way
of converting binary data to a string and back is to use
Convert.To/FromBase64Strin g.

I'm not sure about your IV usage, either...

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

[Jon Skeet [C# MVP]]

Beeeeeeeeeeeeve s <Be************ **@discussions. microsoft.com> wrote:

The second thing you're doing wrong is assuming that any random piece
of binary data can be converted to UTF-8 and back losslessly.
Oh, well excuse me for assuming! Not that I'm blaming its presence on
you or anything, but would you possibly care to enlighten me on what
the BLOODY HELL UTF8 is GOOD FOR then??!!!??!!

Sure. It's a good way of encoding character data in binary. The fact
that any text string can be encoded to binary data using UTF-8
*doesn't* mean that every piece of binary data is a valid UTF-8
representation of a string.

By the way, shouting, being ungrateful and making pretty much repeat
posts isn't likely to get you answers any quicker. On the contrary,
people may well decide to ignore you instead of answering you.
Just as

the *input* to encryption is binary, so is the output. The easiest way
of converting binary data to a string and back is to use
Convert.To/FromBase64Strin g.

And this won't eat any of my information??

No. The resulting string will be 4/3rds the size of the original binary
data though.

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