# Detect tampered and deepfake Resident Registration Card (South Korea) > The Resident Registration Card, 주민등록증, is South Korea's national ID for citizens aged seventeen and over, issued by the local mayor under the Ministry of the Interior and Safety. Its thirteen-digit registration number encodes the birth date and a gender-and-century digit, so a card whose number disagrees with the stated holder shows it directly, and the absence of any printed expiry is itself a rule a forger can break. **Canonical URL:** https://tampercheck.ai/documents-support/south_korea_id **API document class:** `south_korea_id` **Last updated:** 2026-10-04 --- ## What a genuine Korean resident registration card contains The Resident Registration Number prints as six digits and seven digits: the first six are the birth date as year, month, and day, the seventh marks gender and century, one and two for people born 1900 to 1999 and three and four from 2000, and the last digit is a check digit on older numbers. The front carries name in Hangul, the number, address, issue date, and the issuing authority, while the back records address changes and a fingerprint. Numbers issued from October 2020 use randomly assigned digits after the gender digit, so the legacy check digit does not apply to them and only the birth date and gender digit can be validated. A hanja name beside Hangul is optional, address changes appear in a different style on the back, and no expiry date is printed on the card, so analysis separates legitimate variation from structural contradiction. ## How Korean resident registration card forgeries are made ### RRN birth-date decode Digits one to six carry the birth date. Comparing them with the stated date of birth catches cards assembled from mismatched parts at the number level. ### Gender and century digit The seventh digit marks gender and century. A digit that disagrees with the stated sex or birth century contradicts the card's own number, and the foreign-resident series is not used on a citizen card. ### Era-aware check digit Numbers issued before October 2020 follow a weighted check digit, while newer numbers do not. The analysis applies the legacy check only where it is expected, so valid recent cards are not penalised. ### No-expiry rule The citizen card has no legal validity period and prints no expiry date. A printed expiry on a card presented as a citizen's card contradicts the issuing design. ### Photo and text patching A replaced portrait or an edited name or address line shows as resolution steps and font changes that mark off the edited region. ## What TamperCheck checks on a Korean resident registration card TamperCheck runs 200+ forensic checks across three layers and returns a risk score from 0 to 100 with plain-English findings tied to specific regions of the document. These three carry the most weight on this document class. ### Portrait substitution and face-swap analysis The document is isolated from whatever it was photographed on, then the portrait region is assessed against the card surface around it. A pasted or generated face rarely matches the substrate it was placed onto. ### Date and validity consistency Issue, expiry, and period dates are checked against one another and against the file's own creation metadata, which catches backdating and validity extension. ### Reference and document number checks Document, account, and reference numbers are checked for issuer format conformance and against every other place the same value appears on the page. ### And many more checks The three above are the layers that carry the most weight on a Korean resident registration card. Every upload runs the full suite of 200+ checks regardless of document class, spanning file structure and metadata, pixel-level forensics, font and text rendering, optical and print characteristics, provenance signals, AI-generation signatures, and many more checks. ## Who verifies a Korean resident registration card, and why Korean banks, fintechs, and online platforms. In each case the document is being used to unlock money, access, or a legal status, which is exactly what makes it worth forging. ## How to verify a Korean resident registration card in 4 steps 1. **Photograph every face.** Capture the front and the back flat at full resolution, so the number, issue date, and address block survive close analysis. 2. **Decode the RRN.** Split the number into birth date, gender digit, and remainder, then compare the date and gender digit with the stated holder. 3. **Apply the right check.** Run the legacy check digit only for numbers issued before October 2020, and confirm no expiry date is printed on the card. 4. **Run a forensic check on the file.** The number carries the structural story, and the print carries the edit history. TamperCheck runs 200+ forensic checks including registration-number decoding and patch detection, returning a risk score from 0 to 100 with findings tied to specific regions of the image. ## Frequently asked questions ### What does the Korean resident registration number encode? Thirteen digits: a six-digit birth date, a digit marking gender and century, and the remaining digits. Older numbers end in a check digit, so a number that contradicts the stated birth date or sex was assembled rather than issued. ### Why does a newer card fail the old check digit? Numbers issued from October 2020 use randomly assigned digits after the gender digit and do not encode region of birth, so the legacy check logic does not apply. Only the birth date and gender digit can be validated on those numbers. ### Does a Korean resident registration card expire? No expiry date is printed, because the card has no legal validity period, and citizens apply from age seventeen. A printed expiry on a card presented as a citizen's card is a structural red flag. ### How does TamperCheck verify a Korean ID card? TamperCheck decodes the birth date and gender digit, applies the legacy check digit only where it is expected, confirms no expiry is printed, and inspects the portrait region for patching. Uploads run through a single REST endpoint, are processed ephemerally and not stored, and findings tie to specific regions. ## Related document types - TamperCheck Forensic Report: https://tampercheck.ai/documents-support/forensic_analysis_report - Unknown: https://tampercheck.ai/documents-support/unknown --- Try TamperCheck now: https://tampercheck.ai/dashboard · Docs: https://tampercheck.ai/docs · Pricing: https://tampercheck.ai/pricing