‘In Series vs In Parallel’ and ‘2-Layer vs 2-Entrance

Hitoshi Kokumai
3 min readDec 8, 2021

Can we imagine electric/electronic professionals who are indifferent to the difference between ‘in series’ and ‘in parallel’ circuits? Certainly, no.

Can we imagine security/identity professionals who are indifferent to the difference between ‘in 2-layer’ and ‘in 2-entrance’ deployments of authenticators? Yes, very sadly, quite a few.

More often than not, those security/identity professionals promote biometrics solutions deployed with a default/fallback password in ‘2-entrance (in parallel)’ formation by misleading citizens to believe that it provides the same kind of security that a ‘2-layer (in series)’ formation provides.

The outcome of this pseudo-2FA? Criminals quietly chuckling to themselves among the citizens trapped in a false sense of security.

We have kept sending out this alarm for two decades, and it’s really encouraging to see a rapidly growing number of security/identity experts sharing it recently.

Ref: “Biometrics is to Password what Back door is to Front door”

and also “Get graphs to talk the nature of probabilistic biometrics”

Key References

Quantum Computing and Password Authentication

Removal of Passwords and Its Security Effect

Negative Security Effect of Biometrics Deployed in Cyberspace

External Body Features Viewed as ‘What We Are’

Two-Entrance Formation

Additional References

For Achieving Solid Digital Identity on Information Security Buzz (Mar/2021)

What We Know for Certain about Authentication Factors

Digital Identity for Global Citizens
Image-to-Code Conversion by Expanded Password System

Summary and Brief History — Expanded Password System

Proposition on How to Build Sustainable Digital Identity Platform

Account Recovery with Expanded Password System

History, Current Status and Future Scenarios of Expanded Password System

Availability-First Approach

Update: Questions and Answers — Expanded Password System and Related Issues

< Videos on YouTube>

Slide: Outline of Expanded Password System (3minutes 2seconds)

Digital Identity for Global Citizens (10minutes — narrated)

Demo: Simplified Operation on Smartphone for consumers (1m41s)

Demo: High-Security Operation on PC for managers (4m28s)

Demo: Simple capture and registration of pictures by users (1m26s)

Slide: Biometrics in Cyber Space — “below-one” factor authentication

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Hitoshi Kokumai

Advocate of ‘Identity Assurance by Our Own Volition and Memory’, Inventor of Expanded Password System and Founder of Mnemonic Identity Solutions Limited in UK.