Resident registration number

In the Republic of Korea, a resident registration number (RRN) (; romanized: ) is a 13-digit number issued to all residents of South Korea regardless of nationality. Similar to national identification numbers in other countries, it was used to identify people in various private transactions such as banking and employment. It was also used extensively for online identification purposes, but after 2013 resident registration number cannot be used for identification unless other laws require processing resident registration numbers. Foreigners (except those affiliated with the U.S. military) receive an alien registration number upon registration with a city office, which serves as a substitute for the "resident" registration number on their alien registration card.
Every South Korean citizen within a month of their 17th birthday registers their fingerprint at the government local office and is issued the Resident Registration Card that contains their name, registration number, home address, fingerprint and picture.
Components.
The resident registration number consists of 13 digits, with each digit providing specific information, as illustrated below:
Overseas permanent resident problem.
Every citizen of South Korea automatically receives a resident registration number with seventh digit of 9, 0, 1, 2, 3, or 4 (indicating as a Korean citizen) when one's parents register one's birth in South Korea. Therefore, foreign born citizens of South Korea do not automatically receive a resident registration number even after they obtain their Korean passports through Korean diplomatic offices. Foreign born citizens can have resident registration numbers with seventh digit of 9, 0, 1, 2, 3, or 4 by visiting South Korea and registering their births, but the South Korean Immigration Bureau considered foreign born citizens with overseas permanent resident status as foreigners and did not issue a resident registration number with seventh digit of 9, 0, 1, 2, 3, or 4 to foreign born citizens with overseas permanent resident status. Since a resident registration number with seventh digit of 9, 0, 1, 2, 3, or 4 is required to exercise rights of citizenship, citizens without a resident registration number were not guaranteed rights of citizenship except diplomatic protection.
As of 2016, holders of South Korean passports with overseas residency are now eligible for a resident registration number with seventh digit of 9, 0, 1, 2, 3, or 4 regardless of their permanent resident status. They are exempted from taxation and conscription in South Korea, but they can exercise their rights of citizenship such as voting. They still have to apply for a RRN in South Korea.
Online use.
Many South Korean websites require users to submit a valid resident registration number to create an account. This practice ties each registered account to a unique online identity, rather than allowing anonymous registration. Since only a few large websites allow alternate means of identification (such as an alien registration number or passport number), foreigners are unable to use some of South Korean websites.
The principal means of validating a resident registration number is to use an algorithm to check the last digit against what it should be based upon the rest of the digits entered (i.e. checksum verification) however this only ensures it is a valid number but does not authenticate the user.
On 26 July 2011, a hacking incident of SK Communications (owner of NateOn, South Korea's most popular messenger) took place, during which about 70% of all Korean citizens' numbers were hacked. As a result, all South Korean websites were obliged to delete and are no longer allowed to use the number except for payments. The RRN has since replaced the number with identification SMS (via phone owners' information), public key certificate (requiring a visit to a bank, since PKC is stored in user's PC or personal device unlike other countries), and i-PIN, Internet Personal Identification Number, which may be obtained via registration of RRN with a governmental site.
Fraud.
Since many South Korean websites require a valid resident registration number (RRN) in order to create an account, this presents many opportunities for identity theft and other types of fraud. For example, it was found that former South Korean president Roh Moo-hyun's resident registration number was used to gain access to hundreds of pornographic websites, as well as entertainment and gaming websites.
Identity theft and other fraud is difficult to defeat in Korea, because each person's RRN is unchangeable, unlike other nation's identification numbers which can be changed if they are compromised (such as the United States' SSN). Complaints about identity theft led the South Korean government to implement stiff penalties for using someone else's resident registration number. Offenders may serve three years in jail or pay a ₩10,000,000 fine.