OpenSAML user discussion

Thanks Brent very much .The problem has been solved. :)

> Well, if you're sure you are validating with the right key, then it
> almost certainly must be the case that the SignedInfo element really has
> been modified since it was signed. You'll need to double-check the
> serialization process on the signer side, and the deserialization and
> unmarshalling process on the receiving side, to find out where and how. 
> That's all I can tell you.

> Remember that any change to the signed document will cause the signature
> to fail, even something as trivial as addition or removal of whitespace.

  I have double-checked my Saml Assertion, I found, the difference between 
the Assertion from sender and the Assertion received at SP  is the former had 
more '/n' than the latter. I thought this was the reason of 
SignatureValidator.validate(..) failed. Then I encoded the Saml Assertion 
used Base64 before sending, just as expected, the 
SignatureValidator.validate(..) passed.
 Now I want to know  whether the Assertion must be encoded before sending to 
SP?