Behind the curtain: Oblivious Transfer

Lyubomir Filipov @FilipovG

Who am I

Lyubomir Filipov

Team Lead

Enthusiast

Oblivious transfer

cryptographic primitive

1-out-of-2 OT: Alice chooses as input two bits b0 and b1. Bob chooses a selection bit c and gets as output the bit bc.

Bananas in Pyjamas

Oblivious transfer

Alice should not learn c
Bob should not learn b1-c

Alice

Bob

Oblivious transfer

Only one item is returned to Bob.
Alice won't know what Bob has in his mind!

Oblivious transfer

Biometric data

personal data resulting from specific technical processing relating to the physical, physiological or behavioural characteristics of a natural person, which allow or confirm the unique identification of that natural person.

Biometric data

Fingerprint scanning

Iris recognition

Biometric data

Not 100% perfect

Every scan will return different results

Data representation

Hamming distance

Privacy-preserving biometric identification

Anonymous Biometric access Control
Biometric Anonymous Credentials
Secure Biometric Database Intersection

Biometric identification

SHADE protocol

X	Y	X XOR Y
0	0	0
1	0	1
0	1	1
1	1	0

SHADE protocol

Where it could be applied

Dating app where you only want to receive messages from one user.
IoT devices that send sensitive data.

But, wait

To be aware of

All this comes as extra traffic
It could not be extended easily

Questions?

Behind the curtain: Oblivious Transfer

By Lyubomir Filipov

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