Forensics and Security Analysis -- A Multi-Level Feature Enhancement Network for Image Splicing Localization -- MSA-CNN: Face Morphing Detection via a Multiple Scales Attention Convolutional Neural Network -- Double-Stream Segmentation Network with Temporal Self-Attention for Deepfake Video Detection -- Exposing Deepfake Videos with Spatial, Frequency and Multi-Scale Temporal Artifacts -- On the Security of Encrypted JPEG Image with Adaptive Key Generated by Invariant Characteristic -- Modify the Quantization Table in the JPEG Header File for Forensics and Anti-Forensics -- More Accurate and Robust PRNU-Based Source Camera Identification with 3-Step 3-Class Approach -- Effects of Image Compression on Image Age Approximation -- FMFCC-A: A Challenging Mandarin Dataset for Synthetic Speech Detection -- Watermarking -- A Feature-Map-Based Large-Payload DNN Watermarking Algorithm -- A Robust DCT-Based Video Watermarking Scheme Against Recompression and Synchronization Attacks -- Improved Fluctuation Derived Block Selection Strategy in Pixel Value Ordering Based Reversible Data Hiding -- MasterFace Watermarking for IPR Protection of Siamese Network for Face Verification -- Steganology -- Arbitrary-Sized JPEG Steganalysis Based on Fully Convolutional Network -- Using Contrastive Learning to Improve the Performance of Steganalysis Schemes -- A HEVC Steganalysis Algorithm Based on Relationship of Adjacent Intra Prediction Modes -- Data Hiding Based on Redundant Space of WeChat Mini Program Codes -- Image Block Regression Based on Feature Fusion for CNN-Based Spatial Steganalysis.

This volume constitutes the proceedings of the 20th International Workshop on Digital Forensics and Watermarking, IWDW 2021, held in Beijing, China, in November 2021. The 18 full papers in this volume were carefully reviewed and selected from 32 submissions. The are categorized in the following topical headings: Forensics and Security Analysis; Watermarking and Steganology.