General posts

# Phishing truths

A true story…

This is the text of an email message just received:

Dear customer,
Because of the numerous attempts of fraud suffered by our customers in the last 24 hours,
www.popcredbank.com/blabla…..

Popular Credit Bank

But Popular Credit Bank is not my bank!

Yet they didn’t explicitly say that and they said the truth about the increasing number of recent attempts of fraud…

There’s some truth in a Liar that says “I’m a Liar”….

In the same way, there’s truth in a phishing message that starts by saying “since you are receiving phishing messages…
Sort of a… Self-fulfilling prophecy

# The “dice roll with a given sum” problem

In some exercise taken from combinatorics textbooks you might find a question like: “if you roll 2 dice what is the probability to get 9 for the sum of the 2 dice faces?
The answer is not much difficult and can be intuitively given by enumerating the number of cases that satisfy the given event and dividing that number with the number of all possible outcomes.
But what if you want to find the probability of, say, a sum of 31 when rolling 10 dice, where simple enumeration would require a very long time? Or to find a more general formula for the probability of getting p points as the sum of rolling n dice? Is there such a formula, computable without having to enumerate all the cases?