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Category: Net: Fun

Techy: How secure are credit card numbers

From my “over a year ago” post about test credit and debit card numbers, I did wonder how unique/secure a credit or debit card number is. For example: If I knew “x” digits of your card number, how many possible cards would I have to guess at to hit your credit card number.

I’m basing these findings on a the most common length of credit card numbers – 16 digits.

Number of digits known Number of card possibilities if you have the “check digit” at the end Number of card possibilities if you do not have the “check digit” Observations
16 1 1 You’ve got the whole number anyway!
15 1 1 You can either calculate the missing check digit if that’s the only thing you are missing, or calculate the missing number from the check digit
14 10 100 By covering one number and the final number, you’ve just made it 10 times harder to work out your credit card number!
13 100 1,000  
12 1,000 10,000  
11 10,000 100,000  
10 100,000 1,000,000  
09 1,000,000 10,000,000  
08 10,000,000 100,000,000  
07 100,000,000 1,000,000,000,000  
06 1,000,000,000 10,000,000,000,000  
05 10,000,000,000 100,000,000,000,000  
04 100,000,000,000 1,000,000,000,000,000  
03 1,000,000,000,000 10,000,000,000,000,000  
02 10,000,000,000,000 100,000,00,000,000,000  
01 100,000,000,000,000 1,000,000,000,000,000,000 This could just be the check digit

Funny: Funny Linux Commands

Shamelessly stolen from Frank Mash (or, as UK news organisations will probably argue, “this orphaned content found was at …”):

% cat “food in cans”
cat: can’t open food in cans

% nice man woman
No manual entry for woman.

% “How would you rate Quayle’s incompetence?
Unmatched “.

% Unmatched “.
Unmatched “.

% [Where is Jimmy Hoffa?
Missing ].

% ^How did the sex change operation go?^
Modifier failed.

% If I had a ( for every $ the Congress spent, what would I have?
Too many (‘s.

% make love
Make: Don’t know how to make love. Stop.

% sleep with me
bad character

% got a light?
No match.

% man: why did you get a divorce?
man:: Too many arguments.

% !:say, what is saccharine?
Bad substitute.

% %blow
%blow: No such job.

% \(-
(-: Command not found.

$ PATH=pretending! /usr/ucb/which sense
no sense in pretending!

$ drink matter
matter: cannot create

$ ddate
Today is Prickle-Prickle, the 69th day of Chaos in the YOLD 3176

and of course:

unzip ; strip ; touch ; grep ; finger ; mount ; fsck ; more ; yes ; umount ; sleep

Some of these work, some of these don’t – it all depends on your OS version. ddate does work on Centos.

Fun: Plurals or Pluralii?

From Maarten Lippmann:

We’ll begin with box, and the plural is boxes.
But the plural of ox should be oxen, not oxes.
Then one fowl is goose, but two are called geese.
Yet the plural of moose should never be meese.

You may find a lone mouse or a whole lot of mice,
But the plural of house is houses, not hice.
If the plural of man is always called men,
When couldn’t the plural of pan be called pen?

The cow in the plural may be cows or kine,
But the plural of vow is vows, not vine.
And I speak of a foot, and you show me your feet,
But I give a boot – would a pair be called beet?

If one is a tooth and a whole set are teeth,
Why shouldn’t the plural of booth be called beeth?
If the singular is this and plural is these,
Why shouldn’t the plural of kiss be nicknamed kese?

Then one may be that, and three may be those,
Yet the plural of hat would never be hose.
We speak of a brother, and also of brethren,
But though we say mother, we never say methren.

The masculine pronouns are he, his and him,
But imagine the feminine she, shis, and shim!
So our English, I think you will all agree,
Is the trickiest language you ever did see. I take it you already know
Of tough and bough and cough and dough?
Others may stumble, but not you
On hiccough, thorough, slough, and through?

Well done! And now you wish, perhaps,
To learn of less familiar traps?
Beware of heard, a dreadful word
That looks like beard and sounds like bird.

And dead; it’s said like bed, not bead;
For goodness sake, don’t call it deed!
Watch out for meat and great and threat,
(they rhyme with suite and straight and debt).

A moth is not a moth in mother.
Nor both in bother, broth in brother.
And here is not a match for there.
And dear and fear for bear and pear.

And then there’s dose and rose and lose –
Just look them up — and goose and choose.
And cork and work and card and ward,
And font and front and word and sword.

And do and go, then thwart and cart.
Come, come, I’ve hardly made a start.
A dreadful language? Why, man alive,
I’d learned to talk it when I was five.

And yet to write it, the more I tried,
I hadn’t learned it at fifty-five!