Juve are at home for the first leg on Tuesday in a mouth-watering tie that is a repeat of the 2015 final, which Barca won 3-1 in Berlin.
Buffon thinks Juve have closed the gap on Luis Enrique's side since then, but acknowledged the huge task awaiting his side.
"I think we know that in these two games we are meeting the strongest team we could face," Buffon said at Juve's pre-match media conference.
"But it is also true that it is the Champions League and it will be nice to measure ourselves against them.
"I have never seen the final in Berlin again, but I have clear memories of that night which give me reasons to be positive ahead of this match.
"They were much stronger than us, especially in the way they approached the game. Now we have two more years of experience at this level which allows us to play in such games with a different mentality.
"That makes me cautiously optimistic, even if they are stronger on paper. The distance to them has narrowed."
"We already have clarity about who our opponents are and the ability of the team we will be facing, so it shouldn't take us by surprise," added the Italy international.
"Barcelona are probably the most difficult team to knock out over two legs, because often if whether they win or lose is down to their own performance.
"Barcelona have a philosophy and style of play that has been established for many years and has led to the triumphs and success we all know about.
"We have had a different path in the last 10 years, we have had some difficulties but we are finally back at the forefront where we deserve to stay and where our history says we deserve to be."
The Juventus goalkeeper was also quick to pay tribute to Barca's "devastating" attacking trio of Lionel Messi, Luis Suarez and Neymar.
Buffon said: "I don't know how many teams play with three out-and-out strikers like Barcelona.
"I don't want to disrespect the other Barcelona players, but when you have players like Neymar, Messi and Suárez up front it's difficult not to focus on their attack.
"They help each other, they make assists for each other, they play together with a lot of joy and they work together for the team, so everything is very difficult for their opponents. They are unselfish players who have earned a huge amount of respect.
"They have devastating attacking power which any coach would love to have at his disposal."