The correct one in most cases is the Genitiv (as Attribut). That's what you should use in writing. Colloquial German tends to replace the Genetiv-Attribut with von+Dativ (because there's a general tendency to replace the Genitiv, read the article "Der Genitiv ist dem Dativ sein Tod" for more). In a few cases you can also use "von" in writing, but in most cases you shouldn't, unless you're writing in a very colloquial style.

The problem with the some prepositions in German is that you have to be able to differentiate between the one's that take dativ or akkusativ or genetiv. The only way is by practicing. Another thing is that you have to know that this Verb take this Preposition, just like english. Am not trying to scare or anything haha.. am only showing you how to master these rules. At first i almost died trying to undertand them, but after a while of practicing i got the hang of it :).

Mostly you can use both, but using 'von' is more colloquial.