The following content is mainly based on examples compiled from public information and practices in some regions, and does not represent a unified, latest or absolutely accurate national social security card number generation rule. In fact, different regions and periods may formulate different coding schemes based on requirements such as security, anti-counterfeiting, and unified information management. Detailed rules are often internal technical solutions and will not be fully disclosed. Here are two common ideas for reference: ──────────────────────────────── 【Example 1】 Ideas similar to the structure of ID card numbers In some regions, early social security card numbers may refer to some characteristics of resident ID card number coding, usually including the following parts: 1. Regional code: For example, 6 digits are used to represent the issuing area or place of affiliation (similar to the administrative division code). 2. Date of birth or date of issuance: Some schemes may use 8 digits to represent the date of birth or date of issuance of the insured. 3. Sequence code: 3 or more digits are used to represent the sequential serial number in the area to ensure that the same day (or the same batch) is issued without duplication. 4. Check code: The last digit is usually calculated by a certain algorithm (such as the modulo 11 check algorithm) to play an anti-counterfeiting and error correction role. Let’s take a theoretical example (note: the following numbers are for demonstration only and are not authentic): Suppose the social security card number of a certain place is: 320311198901010012. The interpretation is as follows: • 320311: represents the regional code of the place of issuance • 19890101: represents the date of birth of the insured person (January 1, 1989) • 001: represents the sequence code of the region on that day or in the batch • 2: The verification code calculated according to certain verification rules (such as the modulo 11 algorithm) This structure is similar to the resident ID number, but the social security card number may actually have different fields and lengths (for example, it may use 19 digits or a combination of letters) to meet the specific needs of the social security management system. ──────────────────────────────── 【Example 2】Based on the idea of issuing institution and logical coding Another coding scheme may not directly use the individual’s date of birth, but instead emphasize the anti-counterfeiting and uniqueness of the card. It may include the following parts: 1. Issuing institution code: a fixed-length (such as 3 or 4 digits) number or letter used to identify a specific issuing unit or regional sub-center. 2. Random code or internal identification: a longer number used to distinguish between various insured accounts, which may be generated by an algorithm to ensure a certain degree of randomness and unpredictability. 3. Issuance date or version identification: identifies the issuance time or batch of the card, which helps with version management. 4. Check digit: a check digit calculated by a mathematical algorithm to prevent input errors or forgery. For example, suppose a region adopts the following 13-digit logical generation rule: • The first 3 digits: the card issuing institution code (e.g. "123") • The last 10 digits: a digital internal serial number (which may contain the card issuing date and sequence code information), and the last digit is a check code. Then a fictitious card number may be: 1234567890123. The interpretation may be: - "123": represents a card issuing center - "456789012": internal sequence code (part of which may represent the date, such as "4567" represents the year and month of card issuance) - "3": check code, calculated by a predetermined algorithm This scheme pays more attention to internal logic and anti-counterfeiting design, and its specific field length and connotation are entirely dependent on the technical specifications and management needs of the local human resources and social security departments. ────────────────────────────── 【Notes】 1. The specific coding rules, number of digits, check algorithms, etc. implemented in various places may differ, and with the improvement of information security requirements, the new generation of social security cards released later may adopt more complex coding or data encryption technology. 2. The above examples are for illustrative purposes only. The generation of actual numbers involves confidentiality considerations and should not be used for illegal purposes. It cannot be used as a basis for forging or testing real systems. 3. If you need to know the specific generation rules of a certain place or period in detail, it is recommended to refer to the announcements, technical documents or relevant government public information of the local human resources and social security department. In short, the basic principle of social security card number generation is mainly to ensure the uniqueness, anti-counterfeiting and management needs of the number, usually combined with factors such as region, date, sequence code and check code, and the specific implementation details will be continuously adjusted according to policies and security requirements.