And not all 9-digit numbers are used, so there are fewer than a billion. It sucks when organizations store them because the search space is so small it’s relatively easy to unhash them in a stolen database.
A lot of businesses use the last 4 digits separately for some purposes, which means that even if it’s salted, you are only getting 110,000 total options, which is trivial to run through.
And not all 9-digit numbers are used, so there are fewer than a billion. It sucks when organizations store them because the search space is so small it’s relatively easy to unhash them in a stolen database.
A lot of businesses use the last 4 digits separately for some purposes, which means that even if it’s salted, you are only getting 110,000 total options, which is trivial to run through.