Add verify method to HMAC instances to have a comparison utility that does not leak information thr…

Add verify method to HMAC instances to have a comparison utility that does not leak information through timing.


R=ajohnsen@google.com
BUG=

Committed: https://code.google.com/p/dart/source/detail?r=15245

[Anders Johnsen, 2012-11-22 11:34:33]

LGTM

https://codereview.chromium.org/11417138/diff/1/sdk/lib/crypto/crypto.dart
File sdk/lib/crypto/crypto.dart (right):

https://codereview.chromium.org/11417138/diff/1/sdk/lib/crypto/crypto.dart#ne...
sdk/lib/crypto/crypto.dart:50: * block size for the [Hash] it is using.
Maybe more explicit write that it's the internal block size of the hash
function.

https://codereview.chromium.org/11417138/diff/1/sdk/lib/crypto/hmac.dart
File sdk/lib/crypto/hmac.dart (right):

https://codereview.chromium.org/11417138/diff/1/sdk/lib/crypto/hmac.dart#newc...
sdk/lib/crypto/hmac.dart:56: 'Invalid digest size: ${digest.length} in
HMAC.verify.'
Insert '\n' or ' ' at end

https://codereview.chromium.org/11417138/diff/1/tests/lib/crypto/hmac_md5_tes...
File tests/lib/crypto/hmac_md5_test.dart (right):

https://codereview.chromium.org/11417138/diff/1/tests/lib/crypto/hmac_md5_tes...
tests/lib/crypto/hmac_md5_test.dart:107: 
We could add a negative test that tests the exception we throw (as we now
explicit say we do).

[Mads Ager (google), 2012-11-22 11:48:38]

Thanks Anders.

https://codereview.chromium.org/11417138/diff/1/sdk/lib/crypto/crypto.dart
File sdk/lib/crypto/crypto.dart (right):

https://codereview.chromium.org/11417138/diff/1/sdk/lib/crypto/crypto.dart#ne...
sdk/lib/crypto/crypto.dart:50: * block size for the [Hash] it is using.
On 2012/11/22 11:34:33, ajohnsen wrote:
> Maybe more explicit write that it's the internal block size of the hash
> function.

Done.

https://codereview.chromium.org/11417138/diff/1/sdk/lib/crypto/hmac.dart
File sdk/lib/crypto/hmac.dart (right):

https://codereview.chromium.org/11417138/diff/1/sdk/lib/crypto/hmac.dart#newc...
sdk/lib/crypto/hmac.dart:56: 'Invalid digest size: ${digest.length} in
HMAC.verify.'
On 2012/11/22 11:34:33, ajohnsen wrote:
> Insert '\n' or ' ' at end

Done.

https://codereview.chromium.org/11417138/diff/1/tests/lib/crypto/hmac_md5_tes...
File tests/lib/crypto/hmac_md5_test.dart (right):

https://codereview.chromium.org/11417138/diff/1/tests/lib/crypto/hmac_md5_tes...
tests/lib/crypto/hmac_md5_test.dart:107: 
On 2012/11/22 11:34:33, ajohnsen wrote:
> We could add a negative test that tests the exception we throw (as we now
> explicit say we do).

Added that as well as tests that verify returns false when it does not match.