BEIJING, May 25 -- An estimated 1 million people in China had overlapping ID card numbers, a Beijing newspaper reported Monday.

    The replication occurred in the past several years when ID numbers increased from 15 digits to 18 digits, professor Wang Taiyuan with the Chinese People's Public Security University was quoted by The Mirror as saying. The newspaper did not elaborate on how the estimation was made.

    Many of the new numbers were manually created and thus caused the problem, Wang said.

    However, Wang said it would be hard for a person to find another person with a matching identity card number unless both sides used the number for the same purpose, such as applying for a driving license or passport. He said it would be difficult for affected people to change numbers.

    The problem could disappear in the coming years with the ID cards to be changed into the form of IC card connected to a national network, Wang said.

    The first six digits of the ID card indicates the district or county where the cardholder registers, and the seventh to 14th show the person¡¯s birth date.

    The 15th to 17th digits mark the sequence number for people born on the same day who apply for the card in the same district or county, with odd numbers for males and even numbers for females.

    The last digit is a number obtained after calculating the first 17 digits through a formula, with X representing 10.

    This digit was added when the number's digits were increased from 15 to 18, while another two newly added digits were the first digits of the year number in the cardholder¡¯s birth date. 

    (Source: Shenzhen Daily)