"I give failure the somewhat low but still significant probability of 25%. ... According to my estimation, there is a 75% ..." Where are those numbers coming fr

"I give failure the somewhat low but still significant probability of 25%. ... According to my estimation, there is a 75% ..." Where are those numbers coming from? Does it mean that the author believes 1 out of 4 virtual currencies fail? Or that only 3/4 of cryptography algorithms are secure?