Resident registration number

A resident registration number (Korean: 주민등록번호 Jumin Deungrok Beonho, Hanja: 住民登錄番號) is a 13-digit number issued to all residents of the Republic of Korea. Similar to national identification numbers in other countries, it is used to identify people in various private transactions such as in banking and employment. It is also used extensively for online identification purposes. The original usage of this number was the attempt to discover North Korean spies in the aftermath of the Blue House Raid on January 21, 1968. All Koreans who have the number registered their fingerprint to the South Korean government (which is printed on the backside of every RRN card).

Upon registration with the city office, foreigners (except those affiliated with the U.S. military) receive an alien registration number, which serves as a substitute, on their alien registration card.

Components

The resident registration number consists of 13 digits, with each block serving a certain function, as illustrated below:

yymmdd-sbbbbnc

The first six digits signify the person's date of birth; for example, a person born on September 1, 1946, such as former President Roh Moo-Hyun, would have 460901 as the first six digits of his RRN.

s, the seventh digit, indicates the sex and the century in which the person was born:

• 1 – male Korean citizens (born 1900–1999)
• 2 – female Korean citizens (born 1900–1999)
• 3 – male Korean citizens (born 2000–2099)
• 4 – female Korean citizens (born 2000–2099)
• 5 – male foreign citizens residing in Korea (born 1900–1999)
• 6 – female foreign citizens residing in Korea (born 1900–1999)
• 7 – male foreign citizens residing in Korea (born 2000–2099)
• 8 – female foreign citizens residing in Korea (born 2000–2099)

bbbb, the eighth through eleventh digits, signifies place of birth:

• n, the 12th digit, is a sequential number used to differentiate those of the same sex born on the same day in the same location.
• c, the 13th digit, is a check digit, used to verify that the number has been transcribed correctly. It is generated from the rest of the digits using the following algorithm (digits lettered a through m in order):

m = [11 − {(2a + 3b + 4c + 5d + 6e + 7f + 8g + 9h + 2i + 3j + 4k + 5l) mod 11}] mod 10

Online use

Many South Korean websites require the submission of a valid resident registration number in order for users to register an account. This practice ties each registered account to a unique online identity, rather than allowing anonymous registration. Because only a few large websites allow alternate means of identification, such as an alien registration number or passport number, foreigners are unable to use many South Korean websites.

The principal means of authenticating a valid 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.

After SK Communications (Nate ON, most popular messenger at that time in Korea) was hacked on July 26, 2011, which about 70% of all Korean person's number was hacked, all sites of South Korea must delete and can't use the number anymore except payment use. From that time, this number has replaced with receiving identification SMS (using phone owners' information), public key certificate (requiring a visit to a bank/It doesn't secure because PKC is stored in user's PC or personal device not like other countries), and i-PIN (Internet Personal Identification Number, register governmental site with RRN and receive as alternative number, requiring Active X).

Fraud

Many South Korean websites require a valid 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 RRN was used to gain access to hundreds of pornographic websites as well as entertainment and gaming websites. Complaints about identity theft led the South Korean government to implement stiff penalties for using someone else's RRN. Offenders may serve three years in jail or pay a ₩10,000,000 fine.

It cannot stop because unlike like other nation's identification numbers like SSN, each person's RRN is unchangeable.