Implement md5 hash in crypto library.

Implement md5 hash in crypto library.

It might be nicer to leave it out because we do not want to
encourage its use. On the other hand, there are multiple
places where md5 hashing is used so making it available
seems like the right thing to do.

R=sgjesse@google.com,benl@google.com
BUG=
TEST=

Committed: https://code.google.com/p/dart/source/detail?r=7406

[Ben Laurie (Google), 2012-05-03 10:22:01]

How about having a crypto.deprecated library and putting it in there?

[Mads Ager (google), 2012-05-03 11:27:32]

On 2012/05/03 10:22:01, Ben Laurie (Google) wrote:
> How about having a crypto.deprecated library and putting it in there?

We could do that. It would make it harder to discover the md5 hash but that
would of course be part of the point. Make it hard to discover to discourage its
use. I wonder if we have anything else that will end up in the crypto_deprecated
library? If not it seems a bit silly to introduce it only to discourage use of
md5.

[Søren Gjesse, 2012-05-03 13:31:12]

lgtm

I don't think we need to discourage the use if MD5. It must be up to peoples
judgement which algorithms to use. But we could mention the issues in the
library file.

https://chromiumcodereview.appspot.com/10351008/diff/3003/lib/crypto/crypto.dart
File lib/crypto/crypto.dart (right):

https://chromiumcodereview.appspot.com/10351008/diff/3003/lib/crypto/crypto.d...
lib/crypto/crypto.dart:50: * MD5 hash function implementation.
We could mention the issues with MD5 here.

https://chromiumcodereview.appspot.com/10351008/diff/3003/lib/crypto/hash_uti...
File lib/crypto/hash_utils.dart (right):

https://chromiumcodereview.appspot.com/10351008/diff/3003/lib/crypto/hash_uti...
lib/crypto/hash_utils.dart:23: _HashBase(int this._chunkSizeInWords,
Indentation.

[Mads Ager (google), 2012-05-08 08:32:37]

I have added a warning in the doc comment that MD5 has known collisions and
should only be used when needed for backwards compatibility.

I'm going to land this as is. We can consider splitting MD5 into a separate
library for "non-secure crypto stuff". I'm not convinced at this point that it
will have an effect that the comment in itself will not have.

https://chromiumcodereview.appspot.com/10351008/diff/3003/lib/crypto/crypto.dart
File lib/crypto/crypto.dart (right):

https://chromiumcodereview.appspot.com/10351008/diff/3003/lib/crypto/crypto.d...
lib/crypto/crypto.dart:50: * MD5 hash function implementation.
On 2012/05/03 13:31:12, Søren Gjesse wrote:
> We could mention the issues with MD5 here.

Done.

https://chromiumcodereview.appspot.com/10351008/diff/3003/lib/crypto/hash_uti...
File lib/crypto/hash_utils.dart (right):

https://chromiumcodereview.appspot.com/10351008/diff/3003/lib/crypto/hash_uti...
lib/crypto/hash_utils.dart:23: _HashBase(int this._chunkSizeInWords,
On 2012/05/03 13:31:12, Søren Gjesse wrote:
> Indentation.

Done.