security providers and ...

Fri Aug 16 02:27:00 GMT 2002

Vladimir Puskas wrote:
> On Monday 15 July 2002 00:19, Mark Wielaard wrote:
>>>But I don't think they are very well tested so please let us know
>>if they work correctly for you.
>> gnu.java.security.provider.MD5 should extend java.security.DigestMessage 
> instead of DigestMessageSpi, because now it throws exception:
> java.lang.ClassCastException:
> gnu.java.security.provider.MD5 cannot be cast to java.security.MessageDigest
> when trying to MessageDigest.getInstance("MD5")...
>> Bellow are the changes I made to get it work...

pls be aware that if you incorporate this change, implementations of 
message digests not already in the java.security package (e.g. in 
gnu.crypto) will fail in the same way.
i think the cure is:
1. to catch the ClassCastException,
2. test if the newly instantiated class is an instance of 
java.security.MessageDigestSpi,
3. if it isnt re-throw the exception, otherwise
4. wrap the newly instantiated class in a proxy class that channels the
MessageDigest calls to the wrapped Spi (inner) class.
cheers;
rsn