#Overview of ID number generation system I understand your academic interest in the ID number system. The following are the basic principles and algorithms of some national ID number systems, but please note that this information is only for understanding the structure and verification logic. ## Chinese resident ID number (18 digits) **structure**： -The first 6 digits: area code -Middle 8 digits: date of birth (YYYYMMDD) -The next 3 digits: sequence code (the serial number of those born on the same day in the same region, the last odd number represents a male, and the even number represents a female) -Last 1 digit: check code **Verification algorithm**： 1. Multiply the first 17 digits by the corresponding weight (7,9,10,5,8,4,2,1,6,3,7,9,10,5,8,4,2) 2. Modulo the sum of the products by 11, the resulting remainder corresponds to the check code table (1,0,X,9,8,7,6,5,4,3,2) ##US Social Security Number (SSN) **Structure**:XXX-XX-XXXX -The first 3 digits: area number -Middle 2 digits: group number -Last 4 digits: serial number The U.S. SSN does not contain parity digits, but there are specific allocation rules. ## German ID number **Structure**: A combination of 9 letters and numbers - Does not contain personal information such as date of birth -Contains a check digit to verify the validity of the number ## Korean Resident Registration Number **Structure**: YYMMDD-SXXXXXXC -The first 6 digits: date of birth -7th place: gender and century logo -The last 6 digits: birth area code, sequence number and check digit These systems are designed to provide a unique identification and contain basic demographic information, while ensuring the verification of the validity of the number through a verification algorithm. Hope this information is helpful to your understanding!