What's the bottom logic of the ID number verification?

In China, the identity card number of every citizen carries a very high density of personal information. It is not just a series of numbers, but a rigorous package of data covering geography, birth time, sex and anti-false algorithms. The verification function provided by this tool strictly validates the validity of the number by means of a front-end algorithm, does not involve any database networking and guarantees absolute privacy.

1. Secrets of the 18th place checker

Many people are confronted with the fact that, when they register on some websites, the provinces they enter are correct and the date of birth, but the system still points to the “unlawful identity card”. It's because of the ID number. 18 places (last) Strict verification 。 It's the first 17 Bit numbers are calculated by a specific weighted factor formula. If any of the numbers entered in the middle is wrong (even if one loses more or less), the first number is calculated 18 bits must not be matched, and the system will immediately recognize that this is a false number or input the wrong number.

2. Why are age, gender and province identified?

This is not magic, but the public code of the national standard (GB 11643-1999):

First two figures: The corresponding provincial administrative codes are 11 for Beijing, 44 for Guangdong and 51 for Sichuan.
Middle 8 bit: The age of the first year of life is the date of his real birth (YYYYMMDD).
Number 17: Odds are allocated to men and evens to women. Therefore, you do not have to tell yourself that the number is correct and that the gender is clear.

3. Information security and privacy protection

For users, the biggest concern is often, "Will my ID number be leaked? ”。 All parse and validate algorithms for this tool Both in your local browser (through pure JavaScript) , which means that once the web page is loaded, you can even disconnect the network to continue using it. You will not be sent any input to any server, and there is no risk of information gathering or leaking.