A common PIN is a guessable PIN
The DataGenetics group found that the three most popular combinations—1234, 1111, and 0000—account for close to 20 percent of all four-digit passwords.
The 4 digit lock has 10,000 combinations. but if you can recall even 1 or 2 digits of your original code, you reduce this down to 1000 or 100 combinations.
Look for the 4-digit code printed on the front of your card just above and to the right of your main credit card number. This 4-digit code is your Card Security Code.
How long would it take to guess a 4-digit PIN? You have 9,999 guesses so if you are not logged out for too many tries and you could key in PINs starting with 0001 going all the way to 9999 at a rate of a PIN every 2 seconds then you are looking at about 5.5 hours to get to 9999.
You can crack more than 10 percent of random PINs by dialing in 1234. Expanding a bit, 1234, 0000, and 1111, make up about 20 percent. 26.83 percent of passwords can be cracked using the top 20 combinations. That would be 0.2 percent of the passwords if they were randomly distributed.
(Although, as Data Genetics acknowledges, you probably shouldn't go out and choose “8068” now that this is public information.) Rounding out the bottom five are “8093,” “9629,” “6835,” and “7637,” which all nearly as rare.
In nearly a decade, people are still using the same passcodes, and “1234” remains the most popular on both iPhone and Android devices.
Use a mix of alphabetical and numeric, a mixture of upper and lowercase, and special characters when creating your unique passphrase. Use unique passwords or passphrases: You should have a unique password for each of your accounts. This way, if one of your accounts is compromised, your other accounts remain secure.
So 9999 is the greatest four-digit number in the number system. Hence it is proved that 9999 is the greatest four-digit number.
∴ Greatest 4 digit number that is a perfect square = 9999 - 198 = 9801.
The worst PIN codes of all time: '1234,' '0000,' '6969'
Don't use a string of numbers like 1234 or 1111. These rank as the first and fourth most common iPhone PINs. Avoid your birth year — or any year from 1950 onward, says Joseph Bonneau of the University of Cambridge, who coauthored the British study. Avoid the last four digits of your Social Security number.
A personal identification number (PIN) is a numerical code used for electronic financial transactions such as debit card purchases and ATM withdrawals. Using a PIN provides extra security for authentication. PINs should be unique and not shared with others. Institutions may provide the PIN or require you to make one.
Along with '1234', other extremely popular choices are '1111' and '0000' - in fact, between them these three make up nearly 20 per cent of all pass codes. Other frequently used PINs are not patterns, but are memorable in other ways - for example, many people seem to use the year they were born.
The smallest 4-digit number in the number system is 1000 since, in such a case that 1 is subtracted from the number it becomes a 3-digit number which is 999 (greatest three-digit number). So, we 1000 is the smallest 4-digit number in the number system. So, 1000 is the smallest four-digit number.
The greatest among these numbers is 4321.
So the required largest 4-digit number is 9965.
7! Almost half of all people chose numbers between 1 and 10. The second-place number was 3, followed by 8, 4, 5, 13, 9, 6, 2, and 11, to round out the top ten choices.