Journalists do try to break encryption on classified documents, and Assange is not being charged with that. The documents were not encrypted and were obtained in cleartext from Manning.
Journalists do not try to break encryption on classified documents (because the case law protecting them for publishing classified information does not protect them if they actively attempt to acquire it), and that is actually one of the acts Assange is charged with if you read the indictment...
I did read the indictments, and they contain no such charge that i can see. Which page do you believe indicates he tried to break encryption on classified documents?