Anil JainMichigan State Universityhttp://biometrics.cse.msu.edu

October 17, 2019

Fingerprints

Contents• Background and Milestones• Applications• Fingerprint Representation

– Manually defined– Learned

• Attacks on Fingerprint System– Presentation attacks (Spoofs)– Template security

• Summary2

Modality Uniqueness Permanence Legacy DataFingerprint Yes Yes Yes

Face No No YesIris Yes Yes No

• Bios: Body; Metron: Measurement• Person recognition using body traits

Biometrics

Biometric system at Dubai airport to use iris and facial scan: No passport or boarding pass required

https://gulfnews.com/uae/transport/new-biometric-system-at-dubai-airport-no-passport-or-boarding-pass-needed-1.66949849 3

Friction Ridge Patterns

Cummins and Midlo, Finger Prints, Palms and Soles, Dover, 19614

Fingerprints

2.5 cm x 1.7 cm

Finger photo

1000 ppi (800 x 550) 5

Fingerprint Milestones

300 B.C.

1839 1869 1883 1900 1905 1924 1972 19991963 2001 2003 2008 2013 2014 20171858 2018

Fingerprint as a personal mark

A Chinese deed of sale with a fingerprint

Early use of fingerprints for Civil applications

(Bengal, India)

Habitual Criminals Act“What is wanted is a means ofclassifying the records ofhabitual criminal, such that assoon as the particulars of thepersonality of any prisoner(whether description,measurements, marks, orphotographs) are received, itmay be possible to ascertainreadily, and with certainty,whether his case is in theregister, and if so, who he is”

First use of fingerprints in

British criminal case

Bertillonage invented

Galton / Henry fingerprint system adopted by Scotland Yard

• Seventeen classes• Whorl (double loop), loop (left and right)

& arch cover 99% of fingerprints

Delta Core

US Congress authorizes DOJ to collect fingerprints and arrest information

Identimat: First commercial use of biometrics

Trauring publishes paper on fingerprint matching in Nature Goldstein et al. publish face recognition paper in Proc. IEEE (1971)

FBI inaugurates full operation

of “IAFIS”

State AFISState AFIS

State AFIS

State AFIS IAFIS

Forensics Other operationsCriminal booking

9/11 terrorist attacks lead to govt. mandates to use biometrics in

regulating intl. travel

US-VISIT TouchIDFaceID

Apple Pay

Supreme Court upholds the constitutional

validity of Aadhaar

“Aadhaar gives dignity to the marginalized. Dignity to the marginalized outweighs privacy,” Justice Sikri

Aadhaar

FBI Next Generation Identification

6

Fingerprint Capture

Noise sources: Distortion, sensor quality, finger condition

Rolled-print Slap/Plain Print Latent Print

7

Applications

Authentication (1:1 match); Search (1:N match)

Mobile Authentication Border Crossing Forensics

8

Aadhaar:World’s Largest Biometric System

• A 12-digit number, unique to each person• To empower residents of India with a

unique identity and a digital platform to authenticate anytime, anywhere

• Established in 2009, ~1.3bn Aadhaar numbers have been issued

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Enrollment

Proof of Identity, address and relationship; DoB

10

De-duplication (1:N Search)

New Applicant …

Enrollment database

Already in D

atabase?Fusion of face, fingerprint, iris

1:1.3 Billion search

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Authentication

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Why Fingerprints?• Each finger has different ridge

characteristics (Individuality)• Accuracy is invariant over time

(Persistence)• Fingerprint evidence is

accepted in courts

Identical twins

Jain, Pankanti, Prabhakar, “On the similarity of Identical twin fingerprints”, Pattern recognition, 2002

13

The Myth of Fingerprints• "Only Once during the Existence of Our Solar

System Will two Human Beings Be Born with Similar Finger Markings". Harper's headline, 1910

• "Two Like Fingerprints Would be Found Only Once Every 1048 Years" Scientific American, 1911

• The individuality of fingerprints has been accepted over time because of relentless repetition and lack of contradiction

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• Given a fingerprint with n minutiae, what is the probability it will share q minutiae with another fingerprint containing m minutiae?

1. M=52m=n=q=26P = 2.40 x 10-30

2. M=52m=n=26, q=10P = 5.49 x 10-4

M = A/C

Individuality

Pankanti, Prabhakar, Jain, On the individuality of fingerprints, IEEE PAMI, 2002 15

Persistence

• 20K subjects with an average of eight impressions over a span of 12 years

• Longitudinal model showed fingerprint accuracy is

• stable over 12 years for which data available

• function of time gap and fingerprint qualityYoon and Jain, Longitudinal Study of Fingerprint Recognition, PNAS, 2015

16

Fingerprint Representation

Global Level-1 FeaturesLocal Level-2 Features (Minutiae)

cores

deltas

ridge-flow

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Fingerprint Alignment

Align fingerprints prior to feature extraction18

Enrolled fingerprint

Fingerprint Comparison

Similarity = 0.9Query fingerprint

19

State of the Art Performance

• Authentication: TAR of 99.9% @FAR = 0.001%• Retrieval (search):

– Plain prints: 99.3% (100K background)– Latent prints: 67.2% (70.2% with image + markup)

C. Watson, et al.. Fingerprint Vendor Technology Evaluation, NISTIR, 2012M. Indovina, et al.. ELFT-EFS Evaluation of Latent Fingerprint Technologies: Extended Feature Sets NISTIR, 2012

Rolled Plain Latent

20

Fingerprint Image Quality

27 false minutiae7 false minutiaeNo false minutiae

21

DeepPrint

Probe

Enrollment

Trained CNN

Trained CNN

192-dim

192-dim

Cosinedistance

22

Engelsma, Kai, Jain, “Learning a Fixed-Length Fingerprint Representation”, arxiv.org/abs/1909.09901, Sept 2019

DeepPrint

• Custom ConvNet with alignment & domain knowledge• BaseNet: Inception v4 stem• Texture Branch: Inception v4• Minutiae Branch: Custom ConvNet

23

ConvNet Training

455K rolled-prints of 38K unique fingers (~12/finger)

January 2005 August 2007 April 2010 July 2013January 2003June 2001

24

Domain Knowledge: Minutiae Map

Encode input fingerprint minutiae as 6-channel heat-map

0! " 60! 60! " 120! 120! " 180!

180! " 240! 240! " 300! 300! " 360!

25

DeepPrint: Minutiae Features

Extract minutiae related features

26

DeepPrint: Texture Features

Extract features complementary to minutiae features

27

DeepPrint Matching

Cosine distance between two 192-D features

Genuine Pair: s = 0.78 Imposter Pair: s = 0.55

28

Fusion of DeepPrint with SDKs

Boosts performance

sminutiae

sDeepPrint

sfinal = sminutiae + sDeepPrint

29

Two-stage Fingerprint Search

Value of k is a tradeoff between accuracy and speed; k = 500 for 1.1 Million gallery

30

Wang, Otto, Jain, Face Search at Scale. IEEE PAMI, 39(6), pp.1122-1136, 2016

Datasets & SDKNIST SD4 (2000 pairs); NIST SD14 (2700 pairs)

DeepPrint vs. Verifinger

1: Template size fixed at 200 bytes, irrespective the number of minutiae

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Authentication (1:1 Comparison)Rolled-Prints (TAR @ FAR = 0.01%)

Slap-Prints: FVC 2004 (TAR @ FAR = 0.1%); rolled prints of better quality

Two-stage Search

Competitive with top COTS; orders of magnitude faster search

Rank-1 retrieval (1.1 Million gallery)

1

33

Encrypted Authentication

Utilize Fully Homomorphic encryption (FHE) to match a client’s template in the encrypted domain on a server; encrypted scores sent back to client

Boddeti, “Secure Face Matching Using Fully Homomorphic Encryption”, BTAS 2018

• Encrypt features; match in encrypted domain• Never decrypt features to match!

34

Encrypted Authentication

Some drop in accuracy, but encrypted authentication is NOT POSSIBLE with minutiae-based (variable length) representation

35

DeepPrint Interpretability

1. What is DeepPrint fixating on? 2. Does it look at minutiae related features?3. Are fixations in texture and minutiae-

related branches complementary?

36

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Recognition of Infants

6 hours old 2 days old 3 months old

Approximately, 130M newborns every year 38

Fingerprint Spoofs

39

Summary• DeepPrint is first of a kind representation

– 200 byte template; fast matching (large-scale search) in encrypted domain (user privacy); comparable accuracy to COTS SDKs

• Ongoing Research– Large synthetic fingerprint database for search– Can images be reconstructed from DeepPrint?– Retrain DeepPrint on infant fingerprints