In this paper, we introduce a simple yet effective tabular data watermarking mechanism with statistical guarantees. We show theoretically that the proposed watermark can be effectively detected, while faithfully preserving the data fidelity, and also demonstrates appealing robustness against additive noise attack. The general idea is to achieve the watermarking through a strategic embedding based on simple data binning. Specifically, it divides the feature's value range into finely segmented intervals and embeds watermarks into selected ``green list" intervals. To detect the watermarks, we develop a principled statistical hypothesis-testing framework with minimal assumptions: it remains valid as long as the underlying data distribution has a continuous density function. The watermarking efficacy is demonstrated through rigorous theoretical analysis and empirical validation, highlighting its utility in enhancing the security of synthetic and real-world datasets.
Figures & tables
Figure 1: Overview of the tabular data watermarking scheme.
Figure 2: Illustration of our proposed watermarking scheme for tabular data. Specifically, our scheme consists of three major steps: i) dividing the continuous interval [0,1] into 2m equal parts, forming m pairs of consecutive intervals; ii) randomly selecting one interval from each pair, resulting in the set of m “green list” intervals; and iii) sampling new fractional part for the input element from the nearest “green list” interval if the original fractional part falls outside of this interval.
Figure 3: KDE plots for the Gaussian data w/ and w/o our proposed watermark; wm as the shorthand of our watermark; figs and tabs henceforth follows this format.
Figure 5: Detection rates of the proposed watermark applied to tabular data with different number of rows and columns. In Figs. 5(c) and 5(d) we plot the detection rates of the watermark after adding noises with different level of variances (in log10 scale). prp is the proportion of the elements in a table being modified. Rates over 1000 independent samples; error bars over 3 runs. Zoom-in for more details.
California
Gesture
House
Wilt
Higgs-small
Miniboone
Orig2Gen
0.0222
0.0602
0.0315
0.0767
0.0142
0.0161
Gen2Watermarked
0.0004
0.0004
0.0004
0.0005
0.0003
0.0001
m
1000
1000
1000
1000
1000
2500
1/m
0.001
0.001
0.001
0.001
0.001
0.0004
Table 1: Wasserstein-1 distance between generated data distribution and watermarked data distribution.
California
Gesture
House
Wilt
Higgs-small
Miniboone
TVAE
1.000
1.000
1.000
1.000
1.000
1.000
CTABGAN
1.000
1.000
1.000
1.000
1.000
1.000
TabDDPM
1.000
1.000
1.000
1.000
1.000
0.999
Table 2: Accuracy (ROC-AUC score) of the tabular data watermark.
California
Gesture
House
Wilt
Higgs-small
Miniboone
TVAE
1.000
1.000
1.000
1.000
1.000
1.000
CTABGAN
1.000
1.000
1.000
1.000
1.000
1.000
TabDDPM
1.000
1.000
1.000
1.000
1.000
0.999
Table 3: Accuracy (ROC-AUC score) of the tabular data watermark after additive noise attack.
Generator
California (R2)
Gesture (F1)
House (R2)
TVAE
0.736±0.004
0.418±0.012
0.448±0.010
orig. data
CTABGAN
0.577±0.007
0.411±0.005
0.327±0.008
TabDDPM
0.823±0.003
0.575±0.009
0.638±0.007
TVAE
0.735±0.037
0.419±0.012
0.449±0.011
wm. data
CTABGAN
0.577±0.007
0.409±0.009
0.328±0.007
TabDDPM
0.823±0.003
0.554±0.007
0.638±0.007
Table 4: Impact of the tabular data watermark on utility. The metrics used for each dataset is provided after the dataset name. Results calculated using 20 generated copies of the original dataset.
Appendix figures & tables8 assets
Supplementary material from the paper’s appendix.
Appendix
Alias
Name
#Train
#Validation
#Test
#Num
#Cat
Task type
California
California Housing
13209
3303
4128
8
0
Regression
Gesture
Gesture Phase
6318
1580
1975
32
0
Multiclass
House
House 16H
14581
3646
4557
16
0
Regression
Wilt
Wilt
3096
775
968
5
0
Binclass
Higg-small
Higgs Small
62751
15688
19610
28
0
Binclass
Miniboone
MiniBooNE
83240
20811
26013
50
0
Binclass
Appendix
Table A1 : List of datasets used for the evaluation and their descriptions.
n×p
10×10
10×100
10×1000
AUC
0.850
0.700
0.580
n×p
100×10
100×100
100×1000
AUC
1.000
1.000
0.970
n×p
1000×10
1000×100
1000×1000
AUC
1.000
1.000
1.000
Appendix
Table A2 : Detection results on watermarking a single column in simulated tables.
n×p
100×100
100×1000
100×10000
TPR/TNR
1.000/1.000
1.000/1.000
1.000/1.000
AUC
1.000
1.000
1.000
Appendix
Table A3 : Detection results on simulated high dimensional tables. We report the true postive (TPR) and true negative rates (TNR) as well as ROC-AUC scores. We create 100 watermarked and unwatermarked tables to calculate the scores.
s=0.001
s=0.1
s=1
s=10
p=0.50
1.000
1.000
1.000
1.000
p=0.75
1.000
1.000
1.000
1.000
p=0.90
1.000
0.970
0.990
0.870
p=0.95
1.000
0.780
0.850
0.690
Appendix
Table A4 : Detection results after attacks on watermarking a single column in simulated tables. s represents the variances of additive noises; p represents the proportions of elements being modified by the attacks.
California
Gesture
House
Wilt
Higgs-small
Miniboone
TVAE
8/8
32/32
16/16
5/5
24/28
50/50
CTABGAN
8/8
32/32
16/16
5/5
24/28
50/50
TabDDPM
5/8
32/32
7/16
5/5
24/28
27/50
Appendix
Table A5 : Number of columns selected for each generated dataset.
California
Gesture
House
Wilt
Higgs-small
Miniboone
Orig2Gen
0.1327
0.1198
0.0658
0.0906
0.1797
0.6720
Gen2Watermarked
0.0004
0.0004
0.0004
0.0003
0.0003
0.0004
m
1000
1000
1000
1000
1000
1000
1/m
0.001
0.001
0.001
0.001
0.001
0.001
Appendix
Table A6 : Wasserstein-1 distance between TVAE generated data and watermarked data distributions.
California
Gesture
House
Wilt
Higgs-small
Miniboone
Orig2Gen
0.1683
0.1771
0.0926
0.1003
0.0606
0.6471
Gen2Watermarked
0.0004
0.0004
0.0004
0.0004
0.0004
0.0004
m
1000
1000
1000
1000
1000
2500
1/m
0.001
0.001
0.001
0.001
0.001
0.0004
Appendix
Table A7 : Wasserstein-1 distance between CTABGAN generated data and watermarked data distributions.
Figure A1 : Histogram of spiky column data distributions. Examples generated by TabDDPM.