Missing encoding payload for Facebook

[scastrec]

Hi,

In your verifySignature you forgot to encode the payload before sha1.
The payload has to be encoded in unicode like written in Facebook doc:
https://developers.facebook.com/docs/messenger-platform/webhook-reference#security

Be careful, most of time in java, unicode use uppercase encoding and that won't work.

Source file:
https://github.com/spring-projects/spring-social-facebook/blob/master/spring-social-facebook-web/src/main/java/org/springframework/social/facebook/web/RealTimeUpdateController.java

Thanks