Counterfactual communication is a communication without particles in the transmission channel. Since there are no particles to observe, it apparently cryptographically secure because Eve has nothing to eavesdrop on. However, the issue is highly controversial. I will describe: interaction-free measurements, counterfactual key distribution, and direct counterfactual communication protocols. Analyzing the weak trace left in the transmission channel, I will argue that counterfactual communication is possible only for one bit value.