I don't have a clue... what is "Giveawayseekers" and is it some kind of crypto? I don't understand your question in the OP at all. You have some 10 digit number and want to give something to somebody based on that number?
Ah Giveawayseekers are those who participate on the giveaway. Don't know if this word is in the dictionary
Heres the question in a more clear way:
1) People who participate give me a ten digit number.
2 ) I have to choose a lucky winner based on that number!
3) I need the Probably Fair algorith to choose the winner! (I need only one winner).
Hope you understand!