Legal basis: Article 3 of the Law of the People's Republic of China on Resident Identity Cards * * * The citizenship number is a unique and life-long valid identity code for every citizen, which is compiled by the public security organ according to the national standard of citizenship number. According to the national standard GB 11643-1999 of People's Republic of China (PRC), the resident ID number is a feature combination code, which consists of 17-bit ontology code and1bit check code. The order from left to right is: six-digit address code, eight-digit date of birth code, three-digit serial code and one-digit check code.