Explain like I'm five · InfoSec

What are Accredited and Private Certificates?

Accredited (공인) vs. private (사설) certificates, told as a story comparing the days when only state-designated seal-shops got special standing with today's many equal shops.

only state-designated seal-shops got special standingeven to buy a loaf of bread, you had to stop here firstsame, even to file a government paper

There was a time when only state-designated seal-shops got special standing.The accredited certificate. The law gave stronger effect only to seals from the state-designated shops.

the seal rides in a special box and fails at other castlesinconvenient as it was, the law favored the state-designated shops

The certificate was inconvenient, but there was no other option.The certificate had to be carried around in a special box (security software), and moving it to another computer was a hassle.

the Joint Certificate (the old mandatory one)private certificates, like KakaoPay or Tosscarrier PASS authenticationnow no shop gets special legal standingthe amended Digital Signature Act (2020) ended the privilege and opened up the choice

The law changed, and now there are several seal-shops.The 2020 amendment to the Digital Signature Act ended the accredited certificate's special legal status — several private certificates used for identity verification now carry the very same legal weight.

The law ended the privilegethe Digital Signature Act, amended in 2020
Several shops sprang upKakaoPay, Toss, PASS, Naver, and more
Equal legal effectthe accredited certificate's extra legal weight is gone
The underlying tech (PKI) is unchangedwhat changed was the law, not the cryptography
before 2020only the accredited certificate got stronger legal effectsecurity software often had to be installedafter 2020many private certificates carry equal effectsimple app-based authentication is enoughthe ID card's structure didn't change — the legal special treatment did

Before and after the 2020 amendment, side by side.The ID card (the certificate) itself is structurally unchanged — what changed is the special legal treatment of certain issuers.

the stamping mechanism (PKI) is the same as before the amendmentwhich shop to trust still matters just as muchthe law changed — the principle behind the king's seal did not

What changed was the law — not the underlying cryptography.The actual mechanism for stamping and checking the seal is still plain old PKI. → the badge with the king's seal

In one breath

Only the accredited certificate, issued by state-designated authorities, used to carry stronger legal effect, but the 2020 amendment to the Digital Signature Act ended that privilege, giving several private certificates equal legal standing.

After the 1999 Digital Signature Act, only government-designated accredited certificate authorities (five or six depending on the period, including KFTC) could issue an accredited certificate, which carried a stronger legal presumption than private electronic signatures. The 2020 full revision of the Act, in force that December, abolished that special status; the old certificate survives as the renamed '공동인증서' (Joint Certificate), now standing on equal legal footing with other private certificates like KakaoPay, PASS, and Naver. Technically, the accredited certificate and the major private ones all run on PKI (Public Key Infrastructure) — what changed was the legal status, not the cryptography.

When grown-ups say it

Accredited certificate
The seal the law once treated as special. Renamed '공동인증서' (Joint Certificate) after the 2020 amendment.
Private certificate
The new, other seal-shops. KakaoPay, PASS, Naver, and more — now carrying equal legal effect.
Digital Signature Act
The law that decides who may run a seal-shop. The 2020 full revision ended the accredited certificate's special status.
Joint certificate
The old accredited certificate's new name. The privilege is gone, but it's still one option among many.
PKI
The actual mechanism for stamping and checking the seal. The accredited certificate and the major private ones run on this. → the badge with the king's seal
Digital signature
The king's seal stamped at the end of a letter. Its validity as a signature can't be denied merely because it's electronic.
Simple authentication
Identity verification done with just one app. Commonly seen across MyData and financial services. → my right to carry my own ledger
Legal presumption
How much trust the law grants it. Once uniquely stronger for the accredited certificate — equalized after the amendment.
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