Authors: Haoyu Chu, Xiaotong Chen, Wei Zhou, Wenjun Cui, Kai Zhao, Shikui Wei, Qiyu Kang
Organizations: School of Computer Science and Technology / School of Artificial Intelligence, China University of Mining and Technology, Xuzhou 221008, China · School of Information Science and Technology, University of Science and Technology of China, Hefei 230026, China
Graph Neural Networks (GNNs) are highly vulnerable to adversarial perturbations in both topology and features, making the learning of robust representations a critical challenge. In this work, we bridge GNNs with control theory to introduce a novel defense framework grounded in integer- and fractional-order Lyapunov stability. Unlike conventional strategies that rely on resource-heavy adversarial training or data purification, our approach fundamentally constrains the underlying feature-update dynamics of the GNN. We propose an adaptive, learnable Lyapunov function paired with a novel projection mechanism that maps the network's state into a stable space, thereby offering theoretically provable stability guarantees. Notably, this mechanism is orthogonal to existing defenses, allowing for seamless integration with techniques like adversarial training to achieve cumulative robustness. Extensive experiments demonstrate that our Lyapunov-stable graph neural flows substantially outperform base neural flows and state-of-the-art baselines across standard benchmarks and various adversarial attack scenarios.
Figures & tables
Fig. 1 : The scratch of the Lyapunov stability module. The black dashed box illustrates the dynamic evolution of the base graph neural flow over the time interval [0,tn] , where the fractional case captures long-range memories by incorporating historical states, unlike the integer-order’s behavior depends solely on the current state. The orange dashed box depicts the projected Lyapunov-stable system, which satisfies the conditions of the Lyapunov’s direct method, where the Lyapunov function is implemented by an input-convex neural network, a fully connected neural network with special properties.
Dataset
# Nodes
# Edges
# Features
# Classes
max # Nodes (for GIA)
max # Edges (for GIA)
Cora
2708
5429
1433
7
60
20
Citeseer
3327
4732
3703
6
90
10
Computers
18333
81894
6805
15
300
150
PubMed
19717
44338
500
3
200
100
TABLE I : Benchmarks details and the attacks’s budgets of graph injection attacks (GIA)
Dataset
Attack
GRAND
IL-GRAND
F-GRAND
FL-GRAND
GBel
IL-GBel
F-GBel
FL-GBel
GCON
IL-GCON
F-GCON
FL-GCON
HANG
Cora
clean
82.24±1.82
88.88±0.97
86.44±0.31
88.95±0.39
79.07±0.46
85.73±0.73
77.55±0.79
86.74±0.93
83.10±0.63
86.97±0.60
82.42±0.89
87.10±0.80
87.13±0.86
PGD
36.80±1.86
79.01±1.24
56.38±6.39
80.76±0.33
63.93±3.88
80.86±0.73
69.50±2.83
82.60±0.67
48.38±2.44
72.71±0.38
56.70±4.36
74.28±0.69
78.37±1.84
TDGIA
40.0±3.52
73.41±1.17
54.88±6.72
78.06±0.39
53.22±2.95
73.67±1.21
56.94±1.82
81.87±0.60
46.43±2.82
60.46 ±3.85
54.24±2.54
77.06±0.73
79.76±0.99
MetaGIA
37.89±1.56
74.64±1.64
53.36±5.31
78.69±0.36
66.74±3.23
82.20±1.66
71.98±1.32
82.84±0.56
52.21±2.71
61.56±1.51
63.97±2.09
67.74±0.92
77.48±1.02
Citeseer
clean
72.52±0.73
75.47±0.64
71.91±0.43
75.66±0.48
74.75±0.28
74.58±0.70
71.09±0.30
75.03±0.47
72.07±0.93
63.08±1.02
73.50±0.43
74.61±0.80
74.11±0.62
PGD
42.20±2.77
71.62±1.39
61.26±1.23
72.04±1.23
47.73±5.87
72.79±0.52
60.78±2.37
73.22±1.23
37.71±7.0
61.03±0.95
54.47±1.0
61.52±0.77
72.31±1.16
TABLE II : Node classification accuracy (%) on graph injection, evasion, non-targeted, black-box attack in INDUCTIVE learning. Results under adversarial attacks that surpass the competing methods are bold . Second best results are with the underline
Dataset
Ptb(%)
GRAND
IL-GRAND
F-GRAND
FL-GRAND
GBel
IL-GBel
F-GBel
FL-GBel
GCON
IL-GCON
F-GCON
FL-GCON
HANG
Cora
0
82.24±1.82
78.56±0.39
81.25±0.89
81.75±0.75
80.28±0.87
79.32±0.49
79.05±0.73
78.40 ±0.18
83.10±0.79
80.67±0.09
80.91±0.54
80.00±0.06
-
5
78.97±0.49
77.04±0.49
78.84±0.57
81.04±0.12
77.70±0.66
77.53±0.47
76.10±0.74
76.26±0.55
77.90±1.14
77.11±0.21
77.80±0.44
76.20±0.33
-
10
75.02±1.25
76.58±0.15
76.61±0.15
80.08±0.29
74.30±0.88
74.19±0.21
74.03±0.47
75.15±0.29
72.53±1.08
75.55±0.20
74.63±1.42
75.20±0.52
-
15
71.43±1.09
76.48±0.17
73.42±0.97
79.83±0.27
72.14±0.69
72.35±0.70
73.01±0.75
74.31±0.63
69.83±0.68
73.99±0.27
73.01±0.78
73.22±0.55
-
20
60.53±1.99
76.48±0.20
69.27±2.10
78.20±0.43
65.41±0.99
72.91±0.48
69.35±1.23
73.64±0.09
57.28±1.62
72.48±0.22
69.23±1.35
72.99±0.39
-
25
55.26±2.14
75.99±0.20
64.47±1.83
76.70±0.60
62.31±1.13
71.72±0.33
67.63±0.93
72.72±0.22
53.17±1.52
70.02±0.73
65.27±1.33
72.17±0.61
TABLE III : Classification accuracy (%) under modification, poisoning, non-targeted attack (Metattack) in TRANSDUCTIVE learning
Dataset
Attack
GRAND
IL-GRAND
FL-GRAND
FL-GRAND+AT
GBel
IL-GBel
FL-GBel
FL-GBel+AT
GCON
IL-GCON
FL-GCON
FL-GCON+AT
HANG
Cora
clean
87.53±0.59
89.12±0.23
89.58±0.60
89.24±0.84
86.13±0.51
86.47±0.58
87.03±1.06
85.79±0.84
84.69±1.10
87.97±0.23
85.53±0.96
87.13±0.86
88.31±0.48
PGD
36.02±4.09
70.01±0.88
72.22±0.64
72.75±0.91
37.16±1.69
59.87±2.26
59.43±2.43
61.35±1.96
35.83±0.71
53.45±1.01
52.96±1.19
53.90±1.24
67.69±3.84
TDGIA
14.72±1.97
58.55±1.34
56.65±2.91
59.32±1.84
15.46±1.98
66.98±2.14
67.54±2.01
69.12±2.46
33.05±1.09
55.14±1.96
54.44±1.40
55.90±2.95
64.54±3.95
Citeseer
clean
74.98±0.45
74.66±0.63
75.03±0.66
74.88±0.59
69.62±0.56
74.56±1.17
74.69±1.19
73.04±0.51
74.84±0.49
64.09±2.48
74.36±1.04
73.51±2.00
74.11±0.62
PGD
38.57±1.94
66.58±0.77
66.79±0.98
67.97±1.16
32.24±1.21
67.02±1.25
66.21±1.50
70.46±2.13
42.78±1.54
52.00±4.27
58.23±4.69
65.23±1.19
67.54±1.52
TDGIA
30.11±1.43
54.91±0.66
54.31±0.86
55.37±0.45
16.26±1.20
75.35±0.58
75.63±0.77
76.09±0.79
33.55±1.10
66.14±1.38
66.46±0.99
67.01±2.04
63.29±3.15
TABLE IV : Node classification accuracy (%) on graph injection, evasion, non-targeted, white-box attack in inductive learning. AT is the abbreviation for adversarial training.
Dataset
Attack
IL-GRAND (w/o ES layer)
IL-GBel (w/o ES layer)
IL-GCON (w/o ES layer)
FL-GRAND (w/o ES layer)
FL-GBel (w/o ES layer)
FL-GCON (w/o ES layer)
Cora
clean
87.77±1.01
86.29±1.07
85.47±0.75
88.18±1.38
85.98±1.53
84.33±0.46
PGD
78.88±0.92
79.75±0.46
70.27±0.72
78.84±1.24
78.00±0.87
70.18±0.89
TDGIA
72.40±0.83
74.06±1.27
69.62±0.96
74.76±1.18
74.78±0.99
76.43±1.31
MetaGIA
76.44±0.89
76.20±0.87
61.50±1.51
76.98±0.58
83.02±1.54
64.08±1.55
Citeseer
clean
73.39±0.85
72.93±0.63
66.70±1.68
73.26±1.08
73.52±1.13
63.47±1.18
PGD
70.79±0.80
71.98±1.41
60.84±0.94
71.21±0.65
72.29±1.37
61.12±0.36
TABLE V: Classification accuracy (%) of the IL- and FL-GNNs without equilibrium-separating (ES) layer on graph injection, evasion, non-targeted attack in inductive learning
Fig. 2 : Training time (s/epoch) and inference time (s) on the Cora dataset with t∈[0,10] and step size of 1.
Attack
# N./E.
FL-GRAND
FL-GBel
FL-GCON
PGD
80/40
73.76±0.52
81.67±0.82
68.14±0.76
120/80
65.39±1.06
77.18±0.99
61.44±1.79
160/120
55.63±2.49
73.56±0.94
56.49±1.37
200/160
52.02±4.91
66.41±0.74
55.23±2.09
TDGIA
80/40
75.20±1.25
79.66±0.85
72.71±0.66
120/80
68.54±0.66
73.58±0.95
59.34±3.99
TABLE VI: Node classification accuracy (%) on graph injection, evasion, non-targeted attack in inductive learning under different attack amplitudes on the Cora dataset. # N./E. means the number of nodes and edges injected.
Fig. 3 : Influence of β on the robust test accuracy on Cora dataset.
Figure 10
Xiaotong Chen received the B.E. degree from Henan University at Kaifeng and M.S. degree from Beijing Jiaotong University(BJTU), China, in 2020 and 2022. She is currently a Ph.D. candidate at the Institute of Information Science, Beijing Jiaotong University, Beijing, China. Her research interests include cross-modal retrieval and multi-modal learning.
School of Computer Science and Technology, Chongqing University of Posts and Telecommunications, Chongqing, China · School of Cyber Security and Information Law, Chongqing University of Posts and Telecommunications, Chongqing, China · Computational Communication Research Center, Beijing Normal University, Zhuhai, China +2