Is it possible for a Central Bank to escape from a deflation trap by 'hiding' information?
It is certainly possible for a central bank to move the economy away from liquidity trap or deflation trap by proper signals. Signals and targets are undoubtedly effective, as this NBER paper discusses http://www.nber.org/papers/w13932. I read an article, which I cannot find now, saying that signalling and targeting by central banks are sometimes more effective than actual policy changes. The problem is that the economy and financial markets have a huge amount of different players with different interests and goals so it is hard to predict with certainty the effect of the CB revealing certain information. 

One thing I have to disagree with is that signalling higher expectations would reduce real interest rates and move the economy away from deflation trap. The equation  it=rt+πt+1 would be more accurate as it+1=rt+1+πt+1. If you write it like that, then you can see that signalling higher inflation expectations would also signal an incoming interest rate hike, given that any central bank has the policy to keep inflation low and stable. When markets expect a rate hike, they reduce their equity and commodity positions (sell stocks, oil, gold etc.) and move into bonds and other cash positions. This sucks the money out of economy and creates more deflation. So if the CB wants to reduce deflation, the ideal strategy would be the opposite: signal sluggish growth and prolonged low interest rates. This is just what Fed has been doing for several years now and, arguably, it has worked. 

I can also add, as @ChingG noted in comments, the CB has to maintain credibility and not lie. On top of hurting its reputation, the central bank board members are also liable to the government for saying the truth. For example, if the Fed Chairwoman lied to Congress, she would be breaking the law. It makes more sense for the CB disclose the true data and to interpret the information the way the CB sees fit and give the signals and targets it deems necessary, but not "hide" information.