IP Library › Granted Patent US 12,609,842
Granted Patent B2
US 12,609,842 · App. 18/778,925 · Granted Apr 21, 2026

Chain of authentication using public key infrastructure

Inventor: Unho Choi (Seoul, KR)
H04L9/3268B60L53/30G05D1/0291G05D1/104G05D1/69G05D1/695G06Q10/0832G06Q20/227G06Q20/321G06Q20/3829G06Q20/389G06Q20/40145H04L9/0825H04L9/14H04L9/3231H04L9/3263H04L9/3265B60L2200/10G06Q20/38215G06Q30/018H04L9/50H04L2209/84
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Quick Facts
Patent No.
US 12,609,842
App. No.
18/778,925
Granted
Apr 21, 2026
Kind
B2
Abstract

A method for sequential authentication based on chain of authentication using public key infrastructure (PKI) is provided. The method includes generating, by a user, a first private key and a first public key corresponding to each other; generating, by an n th service provider, an n th private key and an n th public key corresponding to each other; transmitting, from the user to the n th service provider, a level n key; verifying, by the n th service provider, the level n key; generating, by the n th service provider, a level (n+1) key by concatenating the level n key and the n th public key signed with the n th private key; and transmitting, by the n th service provider, the level (n+1) key to the user, where n is a natural number, and when n=1, the level 1 key is the first public key signed with the first private key.

Claims (25)

1 . A method comprising:

generating, by a first party, a first public key and a second public key that are configured to authenticate access to predetermined digital contents of the first party; and

transmitting, from the first party to a second party, the second public key signed by a private key of the first party, wherein the second public key is specified such that a subset of the digital contents of the first party is authenticated access by using the second public key, and

wherein the first public key and the second public key include a first code and a second code, respectively, that are different from one another; and

wherein the first code is associated with biometric data or a combination of pieces of biometric data of the first party, and the second code is associated with biometric data or a combination of pieces of biometric data of the second party.

2 . The method of claim 1 , wherein both the first code and the second code are associated with biometric data or a combination of pieces of biometric data of the first party.

3 . The method of claim 1 , wherein the first public key authenticates access to a first set of the digital contents of the first party and the second public key authenticates access to a second set of the digital contents of the first party, the second set being a subset of the first set, and

wherein the digital contents that are included in the first set and excluded from the second set are associated with purchase records, delivery records, gifting records, and/or predetermined personal activities.

4 . The method of claim 3 , wherein the predetermined personal activities comprise history of Internet use, virtual space activities, social media activities, metaverse activities, in-game activities, and text messages.

5 . The method of claim 1 , wherein the second public key, when activated, causes data to be erased, a device containing the data to be formatted, and/or the device to be destroyed.

6 . The method of claim 1 , wherein the first party is allowed to designate the digital contents to be authenticated access by using the second public key.

7 . The method of claim 6 , wherein the digital contents designated with the second public key comprise a text, an audio, a movie, or any combinations thereof prepared for a purpose of a will.

8 . The method of claim 1 , wherein the second public key is designated for an heir, an executor, or a family member, who satisfy prerequisite conditions.

9 . The method of claim 1 , wherein the second public key is configured to be automatically activated in response to a device detecting a death of its possessor based on collected bio-signals.

10 . The method of claim 9 , wherein, upon activation of the second public key, predetermined data are forwarded to a predetermined address or URL.

11 . The method of claim 10 , wherein the predetermined data comprise a legacy from the deceased first party.

12 . The method of claim 10 , wherein the predetermined data include data that provide evidence of circumstances associated with the death.

13 . The method of claim 1 , wherein the second public key is manually activated by the first party.

14 . The method of claim 1 , wherein the second public key is configured to be activated after a time period specified by the first party.

15 . The method of claim 1 , wherein the second public key is configured to be deactivated after a time period specified by the first party.

16 . The method of claim 1 , wherein a password is transmitted to a second party to allow the second party to use the second public key with the password.

17 . The method of claim 1 , wherein both the first public key and the second public key correspond to a common private key.

18 . The method of claim 1 , wherein the first public key and the second public key correspond to different private keys.

19 . The method of claim 1 , wherein the second public key is activated by using a corresponding private key stored on a cloud.

20 . The method of claim 1 , wherein the second public key is activated by a biometric signature cross-signed by one or more certification authorities (CA) that have issued a PKI certificate for multi-signing.

Continuity (5)
Continuation 18632751 · Apr 11, 2024
Division 17472068 · Sep 10, 2021
Provisional Application 63089834 · Oct 9, 2020
Provisional Application 63089857 · Oct 9, 2020
Related Publication 20240380614A1 · Nov 14, 2024
References Cited (53)
US 6701435B1 · Numao et al. · 2004 [cited by applicant]
US 6941285B2 · Sarcanin · 2005 [cited by applicant]
US 8316237B1 · Felsher et al. · 2012 [cited by applicant]
US 9101833B2 · Behmaram-Mosavat et al. · 2015 [cited by applicant]
US 9455832B2 · Brown et al. · 2016 [cited by applicant]
US 10681038B1 · Lambert · 2020 [cited by applicant]
US 10776522B1 · McNeil et al. · 2020 [cited by applicant]
US 11558178B2 · O'brien et al. · 2023 [cited by applicant]
US 11587077B2 · Wang · 2023 [cited by applicant]
US 11664996B2 · Choi · 2023 [cited by applicant]
US 12021850B2 · Saint et al. · 2024 [cited by applicant]
US 20020066018A1 · Linnartz · 2002 [cited by applicant]
US 20030115475A1 · Russo et al. · 2003 [cited by applicant]
US 20040172539A1 · Herrewegen · 2004 [cited by examiner]
US 20070198436A1 · Weiss · 2007 [cited by examiner]
US 20080065895A1 · Liu et al. · 2008 [cited by applicant]
US 20080127279A1 · Futa et al. · 2008 [cited by applicant]
US 20080167994A1 · Li · 2008 [cited by examiner]
US 20100131763A1 · Kim et al. · 2010 [cited by applicant]
US 20130262858A1 · Neuman et al. · 2013 [cited by applicant]
US 20130343545A1 · Schiefelbein · 2013 [cited by applicant]
US 20150172056A1 · Meunier et al. · 2015 [cited by applicant]
US 20150269538A1 · Stanchfield · 2015 [cited by applicant]
US 20150312041A1 · Choi · 2015 [cited by examiner]
US 20160127126A1 · Sohn et al. · 2016 [cited by applicant]
US 20160294555A1 · Jakobsson et al. · 2016 [cited by applicant]
US 20170053458A1 · Smith et al. · 2017 [cited by applicant]
US 20170262789A1 · Zhang et al. · 2017 [cited by applicant]
US 20180167208A1 · Le Saint et al. · 2018 [cited by applicant]
US 20180184290A1 · Luo et al. · 2018 [cited by applicant]
US 20180205743A1 · McIver et al. · 2018 [cited by applicant]
US 20180261120A1 · Shiomi · 2018 [cited by applicant]
US 20190089546A1 · Garcia Morchon et al. · 2019 [cited by applicant]
US 20190237176A1 · O'brien et al. · 2019 [cited by applicant]
US 20190349201A1 · FuerstnerUERSTNER · 2019 [cited by applicant]
US 20190379536A1 · Han et al. · 2019 [cited by applicant]
US 20200169460A1 · Bartlett et al. · 2020 [cited by applicant]
US 20200313890A1 · Mondello et al. · 2020 [cited by applicant]
US 20200320527A1 · Zhuang et al. · 2020 [cited by applicant]
US 20220038291A1 · Hong et al. · 2022 [cited by applicant]
US 20230162182A1 · Bartolucci et al. · 2023 [cited by applicant]
US 20230396420A1 · Badrinarayanan et al. · 2023 [cited by applicant]
CN 107810617A · 2018 [cited by applicant]
CN 109328444A · 2019 [cited by applicant]
EP 1672832A1 · 2006 [cited by applicant]
EP 1689143A1 · 2006 [cited by applicant]
EP 3288214A1 · 2018 [cited by applicant]
EP 3258660B1 · 2018 [cited by applicant]
JP 2005124097A · 2005 [cited by applicant]
KR 20190124848A · 2019 [cited by applicant]
IEEE, Ameur Manel et al., “Securing collaborative Web applications” (Re: XP 32272483A), 2012 International Conference on Education and e-Learning Innovations, Tunisia. [cited by applicant]
University of Maryland, Morselli Ruggero et al., “KeyChains: A Decentralized Public-Key Infrastructure” (Ref: XP 93203969A), 2006, USA. [cited by applicant]
Notification of the First Office Action dated Jun. 29, 2025from Chinese Application No. 202180069134.7. [cited by applicant]